Summary： The neuroproteetive effects of escitalopram oxalate in rats with chronic hypoperfusion and the possible mechanism were explored. Chronic hypoperfusion （2-VO） model was prepared and given escitalopram oxala...Summary： The neuroproteetive effects of escitalopram oxalate in rats with chronic hypoperfusion and the possible mechanism were explored. Chronic hypoperfusion （2-VO） model was prepared and given escitalopram oxalate （experimental group） or PBS （control group） after 6 weeks. Eight weeks after the operation, Morris water maze test was carried out to evaluate the learning and memory ability of the rats. The cell proliferation, three-dimensional vascular distribution, cell morphological changes in ischemic area and the plasma vascular endothelial growth factor （VEGF） were detected to explore the possible mechanisms. （1） Morris water maze test showed that the escape latency in the experimental group was significantly shorter than in the control group, while the first quadrant swimming time in the experi- mental group was significantly longer than the control group （both P〈0.01）. （2） Cerebrovascular confo- cal detection results showed that the inside diameter of capillaries was significantly less in the experi- mental group than in the control group; the vascular density was significantly increased in the experi- mental group and the total area of capillaries was also significantly increased in the experimental group as compared with the control group. （3） There was statistically significant difference in BrdU-positive cells in the ischemic brain tissue between the experimental group and the control group （P=0.003〈0.01）. （4） VEGF concentrations in the plasma and the ischemic area were higher in the experimental group than in the control group （P〈0.05）. It was concluded that escitalopram oxalate could significantly im- prove the learning and memory ability of the rats with chronic cerebral ischemia probably by the VEGF-mediated angiogenesis.展开更多
Panax ginseng is a slow-growing perennial plant.Panax ginseng extract has numerous biological activities,including antitumor,anti-inflammatory and antistress activities.Panax ginseng extract also has a cognition-enhan...Panax ginseng is a slow-growing perennial plant.Panax ginseng extract has numerous biological activities,including antitumor,anti-inflammatory and antistress activities.Panax ginseng extract also has a cognition-enhancing effect in rats with alcohol-induced memory impairment.In this study,we partially occluded the bilateral carotid arteries in the rat to induce chronic cerebral hypoperfusion,a wellknown model of vascular dementia.The rats were then intragastrically administered 50 or 100 mg/kg Panax ginseng extract.Morris water maze and balance beam tests were used to evaluate memory deficits and motor function,respectively.Protein quantity was used to evaluate cholinergic neurons.Immunofluorescence staining was used to assess the number of glial fibrillary acidic protein-positive cells.Western blot assay was used to evaluate protein levels of vascular endothelial growth factor,basic fibroblast growth factor,Bcl-2 and Bax.Treatment with Panax ginseng extract for 8 weeks significantly improved behavioral function and increased neuronal density and VEGF and b FGF protein expression in the hippocampal CA3 area.Furthermore,Panax ginseng extract reduced the number of glial fibrillary acidic protein-immunoreactive cells,and it decreased apoptosis by upregulating Bcl-2 and downregulating Bax protein expression.The effect of Panax ginseng extract was dose-dependent and similar to that of nimodipine,a commonly used drug for the treatment of vascular dementia.These findings suggest that Panax ginseng extract is neuroprotective against vascular dementia induced by chronic cerebral hypoperfusion,and therefore might have therapeutic potential for preventing and treating the disease.展开更多
The glymphatic system plays a pivotal role in maintaining cerebral homeostasis.Chronic cerebral hypoperfusion,arising from small vessel disease or carotid stenosis,results in cerebrometabolic disturbances ultimately m...The glymphatic system plays a pivotal role in maintaining cerebral homeostasis.Chronic cerebral hypoperfusion,arising from small vessel disease or carotid stenosis,results in cerebrometabolic disturbances ultimately manifesting in white matter injury and cognitive dysfunction.However,whether the glymphatic system serves as a potential therapeutic target for white matter injury and cognitive decline during hypoperfusion remains unknown.Here,we established a mouse model of chronic cerebral hypoperfusion via bilateral common carotid artery stenosis.We found that the hypoperfusion model was associated with significant white matter injury and initial cognitive impairment in conjunction with impaired glym・phatic system function.The glymphatic dysfunction was associated with altered cerebral perfusion and loss of aquaporin 4 polarization.Treatment of digoxin rescued changes in glymphatic transport,white matter structure,and cognitive function.Suppression of glymphatic functions by treatment with the AQP4 inhibitor TGN-020 abolished this protective effect of digoxin from hypoperfusion injury.Our research yields new insight into the relationship between hemodynamics,glymphatic transport,white matter injury,and cognitive changes after chronic cerebral hypoperfusion.展开更多
The present study established a rat model of vascular dementia induced by chronic cerebral hypoperfusion through permanent ligation of bilateral common carotid arteries.At 60 days after modeling,escape latency and swi...The present study established a rat model of vascular dementia induced by chronic cerebral hypoperfusion through permanent ligation of bilateral common carotid arteries.At 60 days after modeling,escape latency and swimming path length during hidden-platform acquisition training in Morris water maze significantly increased in the model group.In addition,the number of accurate crossings over the original platform significantly decreased,hippocampal CA1 synaptophysin and growth-associated protein 43 expression significantly decreased,cAMP response element-binding protein expression remained unchanged,and phosphorylated cAMP response element-binding protein expression significantly decreased.Results suggested that abnormal expression of hippocampal synaptic structural protein and cAMP response element-binding protein phosphorylation played a role in cognitive impairment following chronic cerebral hypoperfusion.展开更多
3′-Daidzein sulfonate sodium（DSS） is a new synthetic water-soluble compound derived from daidzein,a soya isoflavone that plays regulatory roles in neurobiology.In this study,we hypothesized that the regulatory role...3′-Daidzein sulfonate sodium（DSS） is a new synthetic water-soluble compound derived from daidzein,a soya isoflavone that plays regulatory roles in neurobiology.In this study,we hypothesized that the regulatory role of DSS in neurobiology exhibits therapeutic effects on hippocampal damage and memory impairment.To validate this hypothesis,we established rat models of chronic cerebral hypoperfusion（CCH） by the permanent occlusion of the common carotid arteries using the two-vessel occlusion method.Three weeks after modeling,rat models were intragastrically administered 0.1,0.2,and 0.4 mg/kg DSS,once a day,for 5 successive weeks.The Morris water maze test was performed to investigate CCH-induced learning and memory deficits.TUNEL assay was used to analyze apoptosis in the hippocampal CA1,CA3 regions and dentate gyrus.Hematoxylin-eosin staining was performed to observe the morphology of neurons in the hippocampal CA1,CA3 regions and dentate gyrus.Western blot analysis was performed to investigate the phosphorylation of PKA,ERK1/2 and CREB in the hippocampal PKA/ERK1/2/CREB signaling pathway.Results showed that DSS treatment greatly improved the learning and memory deficits of rats with CCH,reduced apoptosis of neurons in the hippocampal CA1,CA3 regions and dentate gyrus,and increased the phosphorylation of PKA,ERK1/2,and CREB in the hippocampus.These findings suggest that DSS protects against CCH-induced memory impairment and hippocampal damage possibly through activating the PKA/ERK1/2/CREB signaling pathway.展开更多
BACKGROUND： Chronic cerebral hypoxia and ischemia have been shown to be related to occurrence of sporadic Alzheimer＇s disease, and β- and y-secretase play an important role in the generation of β-amyloid protein. ...BACKGROUND： Chronic cerebral hypoxia and ischemia have been shown to be related to occurrence of sporadic Alzheimer＇s disease, and β- and y-secretase play an important role in the generation of β-amyloid protein. Early clinical symptoms in Alzheimer＇s disease patients include learning and memory deficits. OBJECTIVE： To measure learning and memory, as well as β- and β-secretase activities in the hippocampus of a cerebral ischemia/hypoxia rat model with chronic cerebral hypoperfusion. DESIGN, TIME AND SETTING： A randomized, controlled, animal experiment was performed at the Department of Pathology, Capital Medical University from March to December, 2008. MATERIALS： β- and y-secretase activity kits were purchased from R ＆ D Systems, USA. METHODS： Male Sprague Dawiey rats, aged 23 weeks, were randomly assigned to model （n = 56） and sham-surgery （n = 46） groups. Cerebral hypoperfusion rat models were established by bilateral common carotid occlusion. MAIN OUTCOME MEASURES： Morris water maze was used to test changes in escape latency and path length, and β- and y-secretase activities were measured on days 10, 30, 90, and 180 following surgery. RESULTS： Progressive cognitive impairment resulted from 30 days of chronic cerebral hypoperfusion, which lasted for 180 days after cerebral hypoperfusion. β-secretase activity was increased at 10 days after hypoperfusion, which continued until 180 days, with a 14.25% increase compared to the sham-surgery group; y-secretase activity was increased by 10.5%. CONCLUSION： Chronic cerebral hypoperfusion results in impaired spatial memory and upregulated β- and y-secretase activities, which could play an important role in β-amyloid production.展开更多
Chronic cerebral hypoperfusion can lead to neuronal necrosis,trigger inflammatory responses,promote white matter damage,and ultimately result in cognitive impairment.Consequently,chronic cerebral hypoperfusion is an i...Chronic cerebral hypoperfusion can lead to neuronal necrosis,trigger inflammatory responses,promote white matter damage,and ultimately result in cognitive impairment.Consequently,chronic cerebral hypoperfusion is an important factor influencing the onset and progression of vascular dementia.The myelin sheath is a critical component of white matter,and damage and repair of the white matter are closely linked to myelin sheath integrity.This article reviews the role of microglia in vascular dementia,focusing on their effects on myelin sheaths and the potential therapeutic implications.The findings suggest that ischemia and hypoxia cause disruption of the blood-brain barrier and activate microglia,which may worsen blood-brain barrier damage through the release of matrix-degrading enzymes.Microglia-mediated metabolic reprogramming is recognized as an important driver of inflammation.Damage to the blood-brain barrier and subsequent inflammation can lead to myelin injury and accelerate the progression of vascular dementia.Early activation of microglia is a protective response that contributes to the maintenance of blood-brain barrier integrity through sensing,debris-clearing,and defensive mechanisms.However,prolonged activation can trigger a shift in microglia toward the pro-inflammatory M1 phenotype,resulting in myelin damage and cognitive impairment.Triggering receptor expressed on myeloid cells 2 and triggering receptor expressed on myeloid cells 1 have been identified as potential biomarkers for vascular dementia,as both are closely linked to cognitive decline.Although effective clinical treatments for myelin damage in the central nervous system are currently lacking,researchers are actively working to develop targeted therapies.Several drugs,including nimodipine,dopaminergic agents,simvastatin,biotin,and quetiapine,have been evaluated for clinical use in treating microglial and myelin damage.Future research will face challenges in developing targeted therapeutic strategies for vascular dementia,requiring further investigation into the timing,duration,and specific mechanisms of microglial activation,as well as the exploration of new drug combinations and additional therapeutic targets.展开更多
Vascular cognitive impairment and dementia is a debilitating neurological disorder caused by chronic cerebral hypoperfusion,for which no effective causative treatments are currently available.Intermittent hypoxia has ...Vascular cognitive impairment and dementia is a debilitating neurological disorder caused by chronic cerebral hypoperfusion,for which no effective causative treatments are currently available.Intermittent hypoxia has been shown to enhance cerebral blood flow in mice,but its efficacy in a model of vascular cognitive impairment and dementia remains unclear.In this study,we established a mouse model of vascular cognitive impairment and dementia by bilateral carotid artery stenosis.Intermittent hypoxia was induced before and after this stenosis.We found that intermittent hypoxia increased cerebral blood flow,oxygen saturation,and microcirculation in the prefrontal cortex and hippocampus in the model mice,without causing neurovascular damage.Additionally,intermittent hypoxia significantly improved cognitive function in the mouse model of vascular cognitive impairment and dementia,with perconditioning showing greater efficacy than preconditioning.Improvements in cerebral microcirculation and blood flow were positively correlated with cognitive recovery.Even in a mouse model of vascular cognitive impairment and dementia with comorbidities induced by a high-fat,high-fructose diet,intermittent hypoxic perconditioning demonstrated protective effects on cognitive function.Proteomic analysis indicated that mitochondrial protection is a key mechanism,particularly through upregulating NDUFB8 expression and increasing the activity of mitochondrial complex I.These findings suggest that intermittent hypoxia is a potential non-invasive strategy for the prevention and treatment of vascular cognitive impairment and dementia.展开更多
Objective：To observe the therapeutic effect of Yangxue Qingnao Granule（养血清脑颗粒, YXQNG） on cognitive impairment induced by chronic cerebral hypoperfusion and to investigate its impact on oxidative stress,apopto...Objective：To observe the therapeutic effect of Yangxue Qingnao Granule（养血清脑颗粒, YXQNG） on cognitive impairment induced by chronic cerebral hypoperfusion and to investigate its impact on oxidative stress,apoptosis,and the cholinergic system.Methods：Adult male Wistar rats were subjected to chronic cerebral hypoperfusion by permanent occlusion of bilateral common carotid arteries（2-VO）.Thirty rats were randomly assigned to one of the five treatment groups in a 1：1：1：1：1 ratio：sham operation plus normal saline treatment,2-VO plus normal saline treatment,2-VO plus YXQNG at a dose of 2 g·kg（-1）·d^（-1） or 4 g·kg（-1）·d^（-1）, or 2-VO plus rivastigmine 2 mgkg^（-1）·d^（-1）.The Morris water maze test was used to assess the spatial memory retrieval.Apoptosis,total antioxide capacity（T-AOC）,acetylcholine esterase（AchE） and choline acetyl transferase（ChAT） activities in the hippocampus and the cortex were investigated.Results：In the chronic cerebral hypoperfusion model,the 2-VO plus saline treatment resulted in impaired special learning as shown by the significantly prolonged escape latency and shorter swim time in the first quadrant as compared to the sham operation.The impairment was associated with apoptosis and significant decreases in T-AOC,AchE and ChAT activities in the hippocampus and the cortex.Treatment with YXQNG at either 2 g·kg（-1）·d^（-1） or 4 g·kg（-1）·d^（-1） dose,or rivastigmine resulted in significantly shorter escape latencies and longer swim time in the first quadrant.YXQNG at both doses,but not rivastigmine,had significant reduction in apoptosis,and significant increases in T-AOC and ChAT activity in both the hippocampus and the cortex.Unlike rivastigmine,neither dose of YXQNG showed significant reduction in AchE activity.Conclusions：YXQNG ameliorated cognitive impairment induced by chronic cerebral hypoperfusion.The protective effect may be mediated through its regulation of apoptosis and activities of T-AOC and ChAT in the hippocampus and cortex of the rats in the chronic cerebral hypoperfusion model,a mechanism that is different from rivastigmine.展开更多
Cognitive impairment caused by chronic cerebral hypoperfusion(CCH)is associated with white matter injury(WMI),possibly through the alteration of autophagy.Here,the autophagy—lysosomal pathway(ALP)dysfunction in white...Cognitive impairment caused by chronic cerebral hypoperfusion(CCH)is associated with white matter injury(WMI),possibly through the alteration of autophagy.Here,the autophagy—lysosomal pathway(ALP)dysfunction in white matter(WM)and its relationship with cognitive impairment were investigated in rats subjected to two vessel occlusion(2VO).The results showed that cognitive impairment occurred by the 28th day after 2VO.Injury and autophagy activation of mature oligodendrocytes and neuronal axons sequentially occurred in WM by the 3rd day.By the 14th day,abnormal accumulation of autophagy substrate,lysosomal dysfunction,and the activation of mechanistic target of rapamycin(MTOR)pathway were observed in WM,paralleled with mature oligodendrocyte death.This indicates autophagy activation was followed by ALP dysfunction caused by autophagy inhibition or lysosomal dysfunction.To target the ALP dysfunction,enhanced autophagy by systemic rapamycin treatment or overexpression of Beclin1(BECN1)in oligodendrocytes reduced mature oligodendrocyte death,and subsequently alleviated the WMI and cognitive impairment after CCH.These results reveal that early autophagy activation was followed by ALP dysfunction in WM after 2VO,which was associated with the aggravation of WMI and cognitive impairment.This study highlights that alleviating ALP dysfunction by enhancing oligodendrocyte autophagy has benefits for cognitive recovery after CCH.展开更多
Chronic cerebral hypoperfusion can cause progressive demyelination as well as ischemic vascular dementia,however no effective treatments are available.Here,based on magnetic resonance imaging studies of patients with ...Chronic cerebral hypoperfusion can cause progressive demyelination as well as ischemic vascular dementia,however no effective treatments are available.Here,based on magnetic resonance imaging studies of patients with white matter damage,we found that this damage is associated with disorganized cortical structure.In a mouse model,optogenetic activation of glutamatergic neurons in the somatosensory cortex significantly promoted oligodendrocyte progenitor cell(OPC)proliferation,remyelination in the corpus callosum,and recovery of cognitive ability after cerebral hypoperfusion.The therapeutic effect of such stimulation was restricted to the upper layers of the cortex,but also spanned a wide time window after ischemia.Mechanistically,enhancement of glutamatergic neuron-OPC functional synaptic connections is required to achieve the protection effect of activating cortical glutamatergic neurons.Additionally,skin stroking,an easier method to translate into clinical practice,activated the somatosensory cortex,thereby promoting OPC proliferation,remyelination and cognitive recovery following cerebral hypoperfusion.In summary,we demonstrated that activating glutamatergic neurons in the somatosensory cortex promotes the proliferation of OPCs and remyelination to recover cognitive function after chronic cerebral hypoperfusion.It should be noted that this activation may provide new approaches for treating ischemic vascular dementia via the precise regulation of glutamatergic neuron-OPC circuits.展开更多
文摘Summary： The neuroproteetive effects of escitalopram oxalate in rats with chronic hypoperfusion and the possible mechanism were explored. Chronic hypoperfusion （2-VO） model was prepared and given escitalopram oxalate （experimental group） or PBS （control group） after 6 weeks. Eight weeks after the operation, Morris water maze test was carried out to evaluate the learning and memory ability of the rats. The cell proliferation, three-dimensional vascular distribution, cell morphological changes in ischemic area and the plasma vascular endothelial growth factor （VEGF） were detected to explore the possible mechanisms. （1） Morris water maze test showed that the escape latency in the experimental group was significantly shorter than in the control group, while the first quadrant swimming time in the experi- mental group was significantly longer than the control group （both P〈0.01）. （2） Cerebrovascular confo- cal detection results showed that the inside diameter of capillaries was significantly less in the experi- mental group than in the control group; the vascular density was significantly increased in the experi- mental group and the total area of capillaries was also significantly increased in the experimental group as compared with the control group. （3） There was statistically significant difference in BrdU-positive cells in the ischemic brain tissue between the experimental group and the control group （P=0.003〈0.01）. （4） VEGF concentrations in the plasma and the ischemic area were higher in the experimental group than in the control group （P〈0.05）. It was concluded that escitalopram oxalate could significantly im- prove the learning and memory ability of the rats with chronic cerebral ischemia probably by the VEGF-mediated angiogenesis.
基金supported by the National Natural Science Foundation of China,No.81660243the Joint Foundation of Department of Science and Technology of Guizhou Province of China,No.LG[2012]028the Science and Technology Department of Guizhou Province of China,No.qian SY[2015]3041
文摘Panax ginseng is a slow-growing perennial plant.Panax ginseng extract has numerous biological activities,including antitumor,anti-inflammatory and antistress activities.Panax ginseng extract also has a cognition-enhancing effect in rats with alcohol-induced memory impairment.In this study,we partially occluded the bilateral carotid arteries in the rat to induce chronic cerebral hypoperfusion,a wellknown model of vascular dementia.The rats were then intragastrically administered 50 or 100 mg/kg Panax ginseng extract.Morris water maze and balance beam tests were used to evaluate memory deficits and motor function,respectively.Protein quantity was used to evaluate cholinergic neurons.Immunofluorescence staining was used to assess the number of glial fibrillary acidic protein-positive cells.Western blot assay was used to evaluate protein levels of vascular endothelial growth factor,basic fibroblast growth factor,Bcl-2 and Bax.Treatment with Panax ginseng extract for 8 weeks significantly improved behavioral function and increased neuronal density and VEGF and b FGF protein expression in the hippocampal CA3 area.Furthermore,Panax ginseng extract reduced the number of glial fibrillary acidic protein-immunoreactive cells,and it decreased apoptosis by upregulating Bcl-2 and downregulating Bax protein expression.The effect of Panax ginseng extract was dose-dependent and similar to that of nimodipine,a commonly used drug for the treatment of vascular dementia.These findings suggest that Panax ginseng extract is neuroprotective against vascular dementia induced by chronic cerebral hypoperfusion,and therefore might have therapeutic potential for preventing and treating the disease.
基金supported by Grants from the National Natural Science Foundation of China(81873749 and 81801072)。
文摘The glymphatic system plays a pivotal role in maintaining cerebral homeostasis.Chronic cerebral hypoperfusion,arising from small vessel disease or carotid stenosis,results in cerebrometabolic disturbances ultimately manifesting in white matter injury and cognitive dysfunction.However,whether the glymphatic system serves as a potential therapeutic target for white matter injury and cognitive decline during hypoperfusion remains unknown.Here,we established a mouse model of chronic cerebral hypoperfusion via bilateral common carotid artery stenosis.We found that the hypoperfusion model was associated with significant white matter injury and initial cognitive impairment in conjunction with impaired glym・phatic system function.The glymphatic dysfunction was associated with altered cerebral perfusion and loss of aquaporin 4 polarization.Treatment of digoxin rescued changes in glymphatic transport,white matter structure,and cognitive function.Suppression of glymphatic functions by treatment with the AQP4 inhibitor TGN-020 abolished this protective effect of digoxin from hypoperfusion injury.Our research yields new insight into the relationship between hemodynamics,glymphatic transport,white matter injury,and cognitive changes after chronic cerebral hypoperfusion.
基金supported by the National Natural Science Foundation of China,No.30973782the National Natural Science Foundation for the Youth,No.81001693+1 种基金the Natural Science Foundation of Beijing,No.7102014,7122018the Science and Technology Foundation for Chinese Medicine in Beijing,No.JJ2008-042
文摘The present study established a rat model of vascular dementia induced by chronic cerebral hypoperfusion through permanent ligation of bilateral common carotid arteries.At 60 days after modeling,escape latency and swimming path length during hidden-platform acquisition training in Morris water maze significantly increased in the model group.In addition,the number of accurate crossings over the original platform significantly decreased,hippocampal CA1 synaptophysin and growth-associated protein 43 expression significantly decreased,cAMP response element-binding protein expression remained unchanged,and phosphorylated cAMP response element-binding protein expression significantly decreased.Results suggested that abnormal expression of hippocampal synaptic structural protein and cAMP response element-binding protein phosphorylation played a role in cognitive impairment following chronic cerebral hypoperfusion.
基金supported by the National Natural Science Foundation of China,No.81560583the Natural Science Foundation of Jiangxi Province of China,No.20142BAB205021
文摘3′-Daidzein sulfonate sodium（DSS） is a new synthetic water-soluble compound derived from daidzein,a soya isoflavone that plays regulatory roles in neurobiology.In this study,we hypothesized that the regulatory role of DSS in neurobiology exhibits therapeutic effects on hippocampal damage and memory impairment.To validate this hypothesis,we established rat models of chronic cerebral hypoperfusion（CCH） by the permanent occlusion of the common carotid arteries using the two-vessel occlusion method.Three weeks after modeling,rat models were intragastrically administered 0.1,0.2,and 0.4 mg/kg DSS,once a day,for 5 successive weeks.The Morris water maze test was performed to investigate CCH-induced learning and memory deficits.TUNEL assay was used to analyze apoptosis in the hippocampal CA1,CA3 regions and dentate gyrus.Hematoxylin-eosin staining was performed to observe the morphology of neurons in the hippocampal CA1,CA3 regions and dentate gyrus.Western blot analysis was performed to investigate the phosphorylation of PKA,ERK1/2 and CREB in the hippocampal PKA/ERK1/2/CREB signaling pathway.Results showed that DSS treatment greatly improved the learning and memory deficits of rats with CCH,reduced apoptosis of neurons in the hippocampal CA1,CA3 regions and dentate gyrus,and increased the phosphorylation of PKA,ERK1/2,and CREB in the hippocampus.These findings suggest that DSS protects against CCH-induced memory impairment and hippocampal damage possibly through activating the PKA/ERK1/2/CREB signaling pathway.
基金the Natural Science Foundation of Bei-jing, No. 7073088
文摘BACKGROUND： Chronic cerebral hypoxia and ischemia have been shown to be related to occurrence of sporadic Alzheimer＇s disease, and β- and y-secretase play an important role in the generation of β-amyloid protein. Early clinical symptoms in Alzheimer＇s disease patients include learning and memory deficits. OBJECTIVE： To measure learning and memory, as well as β- and β-secretase activities in the hippocampus of a cerebral ischemia/hypoxia rat model with chronic cerebral hypoperfusion. DESIGN, TIME AND SETTING： A randomized, controlled, animal experiment was performed at the Department of Pathology, Capital Medical University from March to December, 2008. MATERIALS： β- and y-secretase activity kits were purchased from R ＆ D Systems, USA. METHODS： Male Sprague Dawiey rats, aged 23 weeks, were randomly assigned to model （n = 56） and sham-surgery （n = 46） groups. Cerebral hypoperfusion rat models were established by bilateral common carotid occlusion. MAIN OUTCOME MEASURES： Morris water maze was used to test changes in escape latency and path length, and β- and y-secretase activities were measured on days 10, 30, 90, and 180 following surgery. RESULTS： Progressive cognitive impairment resulted from 30 days of chronic cerebral hypoperfusion, which lasted for 180 days after cerebral hypoperfusion. β-secretase activity was increased at 10 days after hypoperfusion, which continued until 180 days, with a 14.25% increase compared to the sham-surgery group; y-secretase activity was increased by 10.5%. CONCLUSION： Chronic cerebral hypoperfusion results in impaired spatial memory and upregulated β- and y-secretase activities, which could play an important role in β-amyloid production.
基金supported by the Natural Science Foundation of Beijing,No.7232279(to XW)the National Natural Science Foundation of China,No.U21A20400(to QW)Key Project of Beijing University of Chinese Medicine,Nos.2022-JYB-JBZR-004(to XW),2024-JYB-JBZD-043(to CL).
文摘Chronic cerebral hypoperfusion can lead to neuronal necrosis,trigger inflammatory responses,promote white matter damage,and ultimately result in cognitive impairment.Consequently,chronic cerebral hypoperfusion is an important factor influencing the onset and progression of vascular dementia.The myelin sheath is a critical component of white matter,and damage and repair of the white matter are closely linked to myelin sheath integrity.This article reviews the role of microglia in vascular dementia,focusing on their effects on myelin sheaths and the potential therapeutic implications.The findings suggest that ischemia and hypoxia cause disruption of the blood-brain barrier and activate microglia,which may worsen blood-brain barrier damage through the release of matrix-degrading enzymes.Microglia-mediated metabolic reprogramming is recognized as an important driver of inflammation.Damage to the blood-brain barrier and subsequent inflammation can lead to myelin injury and accelerate the progression of vascular dementia.Early activation of microglia is a protective response that contributes to the maintenance of blood-brain barrier integrity through sensing,debris-clearing,and defensive mechanisms.However,prolonged activation can trigger a shift in microglia toward the pro-inflammatory M1 phenotype,resulting in myelin damage and cognitive impairment.Triggering receptor expressed on myeloid cells 2 and triggering receptor expressed on myeloid cells 1 have been identified as potential biomarkers for vascular dementia,as both are closely linked to cognitive decline.Although effective clinical treatments for myelin damage in the central nervous system are currently lacking,researchers are actively working to develop targeted therapies.Several drugs,including nimodipine,dopaminergic agents,simvastatin,biotin,and quetiapine,have been evaluated for clinical use in treating microglial and myelin damage.Future research will face challenges in developing targeted therapeutic strategies for vascular dementia,requiring further investigation into the timing,duration,and specific mechanisms of microglial activation,as well as the exploration of new drug combinations and additional therapeutic targets.
基金supported by the Beijing Nova Program,Nos.20230484436,Z211100002121038the Chinese Institutes for Medical Research,No.CX23YQ01+1 种基金the NationalNatural Science Foundation of China,Nos.32100925,82027802Beijing-Tianjin-Hebei Basic Research Cooperation Project,No.22JCZXJC00190(all to XJand JL).
文摘Vascular cognitive impairment and dementia is a debilitating neurological disorder caused by chronic cerebral hypoperfusion,for which no effective causative treatments are currently available.Intermittent hypoxia has been shown to enhance cerebral blood flow in mice,but its efficacy in a model of vascular cognitive impairment and dementia remains unclear.In this study,we established a mouse model of vascular cognitive impairment and dementia by bilateral carotid artery stenosis.Intermittent hypoxia was induced before and after this stenosis.We found that intermittent hypoxia increased cerebral blood flow,oxygen saturation,and microcirculation in the prefrontal cortex and hippocampus in the model mice,without causing neurovascular damage.Additionally,intermittent hypoxia significantly improved cognitive function in the mouse model of vascular cognitive impairment and dementia,with perconditioning showing greater efficacy than preconditioning.Improvements in cerebral microcirculation and blood flow were positively correlated with cognitive recovery.Even in a mouse model of vascular cognitive impairment and dementia with comorbidities induced by a high-fat,high-fructose diet,intermittent hypoxic perconditioning demonstrated protective effects on cognitive function.Proteomic analysis indicated that mitochondrial protection is a key mechanism,particularly through upregulating NDUFB8 expression and increasing the activity of mitochondrial complex I.These findings suggest that intermittent hypoxia is a potential non-invasive strategy for the prevention and treatment of vascular cognitive impairment and dementia.
文摘Objective：To observe the therapeutic effect of Yangxue Qingnao Granule（养血清脑颗粒, YXQNG） on cognitive impairment induced by chronic cerebral hypoperfusion and to investigate its impact on oxidative stress,apoptosis,and the cholinergic system.Methods：Adult male Wistar rats were subjected to chronic cerebral hypoperfusion by permanent occlusion of bilateral common carotid arteries（2-VO）.Thirty rats were randomly assigned to one of the five treatment groups in a 1：1：1：1：1 ratio：sham operation plus normal saline treatment,2-VO plus normal saline treatment,2-VO plus YXQNG at a dose of 2 g·kg（-1）·d^（-1） or 4 g·kg（-1）·d^（-1）, or 2-VO plus rivastigmine 2 mgkg^（-1）·d^（-1）.The Morris water maze test was used to assess the spatial memory retrieval.Apoptosis,total antioxide capacity（T-AOC）,acetylcholine esterase（AchE） and choline acetyl transferase（ChAT） activities in the hippocampus and the cortex were investigated.Results：In the chronic cerebral hypoperfusion model,the 2-VO plus saline treatment resulted in impaired special learning as shown by the significantly prolonged escape latency and shorter swim time in the first quadrant as compared to the sham operation.The impairment was associated with apoptosis and significant decreases in T-AOC,AchE and ChAT activities in the hippocampus and the cortex.Treatment with YXQNG at either 2 g·kg（-1）·d^（-1） or 4 g·kg（-1）·d^（-1） dose,or rivastigmine resulted in significantly shorter escape latencies and longer swim time in the first quadrant.YXQNG at both doses,but not rivastigmine,had significant reduction in apoptosis,and significant increases in T-AOC and ChAT activity in both the hippocampus and the cortex.Unlike rivastigmine,neither dose of YXQNG showed significant reduction in AchE activity.Conclusions：YXQNG ameliorated cognitive impairment induced by chronic cerebral hypoperfusion.The protective effect may be mediated through its regulation of apoptosis and activities of T-AOC and ChAT in the hippocampus and cortex of the rats in the chronic cerebral hypoperfusion model,a mechanism that is different from rivastigmine.
基金the Natural Science Foundation of Liaoning Province(LJKQZ2021031,2022-MS-246,China)to Yueyang Liu。
文摘Cognitive impairment caused by chronic cerebral hypoperfusion(CCH)is associated with white matter injury(WMI),possibly through the alteration of autophagy.Here,the autophagy—lysosomal pathway(ALP)dysfunction in white matter(WM)and its relationship with cognitive impairment were investigated in rats subjected to two vessel occlusion(2VO).The results showed that cognitive impairment occurred by the 28th day after 2VO.Injury and autophagy activation of mature oligodendrocytes and neuronal axons sequentially occurred in WM by the 3rd day.By the 14th day,abnormal accumulation of autophagy substrate,lysosomal dysfunction,and the activation of mechanistic target of rapamycin(MTOR)pathway were observed in WM,paralleled with mature oligodendrocyte death.This indicates autophagy activation was followed by ALP dysfunction caused by autophagy inhibition or lysosomal dysfunction.To target the ALP dysfunction,enhanced autophagy by systemic rapamycin treatment or overexpression of Beclin1(BECN1)in oligodendrocytes reduced mature oligodendrocyte death,and subsequently alleviated the WMI and cognitive impairment after CCH.These results reveal that early autophagy activation was followed by ALP dysfunction in WM after 2VO,which was associated with the aggravation of WMI and cognitive impairment.This study highlights that alleviating ALP dysfunction by enhancing oligodendrocyte autophagy has benefits for cognitive recovery after CCH.
基金We would like to thank the Core Facilities,Zhejiang University School of Medicine for technical support.This work was supported by the National Natural Science Foundation of China(81973302,81903580)the National Key R&D Program of China(2020YFA0803900)the Zhejiang Provincial Natural Science Foundation of China(LR17H310001,LYY22H310003).
文摘Chronic cerebral hypoperfusion can cause progressive demyelination as well as ischemic vascular dementia,however no effective treatments are available.Here,based on magnetic resonance imaging studies of patients with white matter damage,we found that this damage is associated with disorganized cortical structure.In a mouse model,optogenetic activation of glutamatergic neurons in the somatosensory cortex significantly promoted oligodendrocyte progenitor cell(OPC)proliferation,remyelination in the corpus callosum,and recovery of cognitive ability after cerebral hypoperfusion.The therapeutic effect of such stimulation was restricted to the upper layers of the cortex,but also spanned a wide time window after ischemia.Mechanistically,enhancement of glutamatergic neuron-OPC functional synaptic connections is required to achieve the protection effect of activating cortical glutamatergic neurons.Additionally,skin stroking,an easier method to translate into clinical practice,activated the somatosensory cortex,thereby promoting OPC proliferation,remyelination and cognitive recovery following cerebral hypoperfusion.In summary,we demonstrated that activating glutamatergic neurons in the somatosensory cortex promotes the proliferation of OPCs and remyelination to recover cognitive function after chronic cerebral hypoperfusion.It should be noted that this activation may provide new approaches for treating ischemic vascular dementia via the precise regulation of glutamatergic neuron-OPC circuits.
