Diabetic retinopathy is a prominent cause of blindness in adults,with early retinal ganglion cell loss contributing to visual dysfunction or blindness.In the brain,defects inγ-aminobutyric acid synaptic transmission ...Diabetic retinopathy is a prominent cause of blindness in adults,with early retinal ganglion cell loss contributing to visual dysfunction or blindness.In the brain,defects inγ-aminobutyric acid synaptic transmission are associated with pathophysiological and neurodegenerative disorders,whereas glucagon-like peptide-1 has demonstrated neuroprotective effects.However,it is not yet clear whether diabetes causes alterations in inhibitory input to retinal ganglion cells and whether and how glucagon-like peptide-1 protects against neurodegeneration in the diabetic retina through regulating inhibitory synaptic transmission to retinal ganglion cells.In the present study,we used the patch-clamp technique to recordγ-aminobutyric acid subtype A receptor-mediated miniature inhibitory postsynaptic currents in retinal ganglion cells from streptozotocin-induced diabetes model rats.We found that early diabetes(4 weeks of hyperglycemia)decreased the frequency of GABAergic miniature inhibitory postsynaptic currents in retinal ganglion cells without altering their amplitude,suggesting a reduction in the spontaneous release ofγ-aminobutyric acid to retinal ganglion cells.Topical administration of glucagon-like peptide-1 eyedrops over a period of 2 weeks effectively countered the hyperglycemia-induced downregulation of GABAergic mIPSC frequency,subsequently enhancing the survival of retinal ganglion cells.Concurrently,the protective effects of glucagon-like peptide-1 on retinal ganglion cells in diabetic rats were eliminated by topical administration of exendin-9-39,a specific glucagon-like peptide-1 receptor antagonist,or SR95531,a specific antagonist of theγ-aminobutyric acid subtype A receptor.Furthermore,extracellular perfusion of glucagon-like peptide-1 was found to elevate the frequencies of GABAergic miniature inhibitory postsynaptic currents in both ON-and OFF-type retinal ganglion cells.This elevation was shown to be mediated by activation of the phosphatidylinositol-phospholipase C/inositol 1,4,5-trisphosphate receptor/Ca2+/protein kinase C signaling pathway downstream of glucagon-like peptide-1 receptor activation.Moreover,multielectrode array recordings revealed that glucagon-like peptide-1 functionally augmented the photoresponses of ON-type retinal ganglion cells.Optomotor response tests demonstrated that diabetic rats exhibited reductions in visual acuity and contrast sensitivity that were significantly ameliorated by topical administration of glucagon-like peptide-1.These results suggest that glucagon-like peptide-1 facilitates the release ofγ-aminobutyric acid onto retinal ganglion cells through the activation of glucagon-like peptide-1 receptor,leading to the de-excitation of retinal ganglion cell circuits and the inhibition of excitotoxic processes associated with diabetic retinopathy.Collectively,our findings indicate that theγ-aminobutyric acid system has potential as a therapeutic target for mitigating early-stage diabetic retinopathy.Furthermore,the topical administration of glucagon-like peptide-1 eyedrops represents a non-invasive and effective treatment approach for managing early-stage diabetic retinopathy.展开更多
目的:验证运用有机溶剂/去污剂(S/D)处理法和干热法对C1酯酶抑制剂(C1-INH)中病毒灭活效果。方法:采用S/D处理法灭活含S/D样品中添加的辛德毕斯病毒,噬斑滴定法检测灭活前后的病毒滴度,-干热法灭活脑心肌炎病毒(EMCV)和猪细小病毒(PPV)...目的:验证运用有机溶剂/去污剂(S/D)处理法和干热法对C1酯酶抑制剂(C1-INH)中病毒灭活效果。方法:采用S/D处理法灭活含S/D样品中添加的辛德毕斯病毒,噬斑滴定法检测灭活前后的病毒滴度,-干热法灭活脑心肌炎病毒(EMCV)和猪细小病毒(PPV),细胞病变法检测灭活前后的病毒滴度。结果:经S/D处理法灭活后,3批含S/D样品中辛德毕斯病毒降低量分别为>4.35 lg PFU·mL^(-1)、>4.51 lg PFU·mL^(-1)、>4.64 lg PFU·mL^(-1)。经干热法灭活后,3批不含S/D样品中EMCV降低量分别为≥5.38 lg TCID_(50)/0.1 mL、≥5.12 lg TCID_(50)/0.1 mL、≥5.25 lg TCID_(50)/0.1 mL,PPV降低量分别为4.57 lg TCID_(50)/0.1 mL、4.18 lg TCID_(50)/0.1 mL、4.68 lg TCID_(50)/0.1 mL。结论:通过对指示病毒的验证效果评估,证明S/D法和干热法对C1-INH中的辛德毕斯病毒、EMCV和PPV均有较好的灭活效果。展开更多
基金supported by the National Natural Science Foundation of China,Nos.32070989(to YMZ),31872766(to YMZ),81790640(to XLY),and 82070993(to SJW)the grant from Sanming Project of Medicine in Shenzhen,No.SZSM202011015(to XLY)。
文摘Diabetic retinopathy is a prominent cause of blindness in adults,with early retinal ganglion cell loss contributing to visual dysfunction or blindness.In the brain,defects inγ-aminobutyric acid synaptic transmission are associated with pathophysiological and neurodegenerative disorders,whereas glucagon-like peptide-1 has demonstrated neuroprotective effects.However,it is not yet clear whether diabetes causes alterations in inhibitory input to retinal ganglion cells and whether and how glucagon-like peptide-1 protects against neurodegeneration in the diabetic retina through regulating inhibitory synaptic transmission to retinal ganglion cells.In the present study,we used the patch-clamp technique to recordγ-aminobutyric acid subtype A receptor-mediated miniature inhibitory postsynaptic currents in retinal ganglion cells from streptozotocin-induced diabetes model rats.We found that early diabetes(4 weeks of hyperglycemia)decreased the frequency of GABAergic miniature inhibitory postsynaptic currents in retinal ganglion cells without altering their amplitude,suggesting a reduction in the spontaneous release ofγ-aminobutyric acid to retinal ganglion cells.Topical administration of glucagon-like peptide-1 eyedrops over a period of 2 weeks effectively countered the hyperglycemia-induced downregulation of GABAergic mIPSC frequency,subsequently enhancing the survival of retinal ganglion cells.Concurrently,the protective effects of glucagon-like peptide-1 on retinal ganglion cells in diabetic rats were eliminated by topical administration of exendin-9-39,a specific glucagon-like peptide-1 receptor antagonist,or SR95531,a specific antagonist of theγ-aminobutyric acid subtype A receptor.Furthermore,extracellular perfusion of glucagon-like peptide-1 was found to elevate the frequencies of GABAergic miniature inhibitory postsynaptic currents in both ON-and OFF-type retinal ganglion cells.This elevation was shown to be mediated by activation of the phosphatidylinositol-phospholipase C/inositol 1,4,5-trisphosphate receptor/Ca2+/protein kinase C signaling pathway downstream of glucagon-like peptide-1 receptor activation.Moreover,multielectrode array recordings revealed that glucagon-like peptide-1 functionally augmented the photoresponses of ON-type retinal ganglion cells.Optomotor response tests demonstrated that diabetic rats exhibited reductions in visual acuity and contrast sensitivity that were significantly ameliorated by topical administration of glucagon-like peptide-1.These results suggest that glucagon-like peptide-1 facilitates the release ofγ-aminobutyric acid onto retinal ganglion cells through the activation of glucagon-like peptide-1 receptor,leading to the de-excitation of retinal ganglion cell circuits and the inhibition of excitotoxic processes associated with diabetic retinopathy.Collectively,our findings indicate that theγ-aminobutyric acid system has potential as a therapeutic target for mitigating early-stage diabetic retinopathy.Furthermore,the topical administration of glucagon-like peptide-1 eyedrops represents a non-invasive and effective treatment approach for managing early-stage diabetic retinopathy.
文摘目的:验证运用有机溶剂/去污剂(S/D)处理法和干热法对C1酯酶抑制剂(C1-INH)中病毒灭活效果。方法:采用S/D处理法灭活含S/D样品中添加的辛德毕斯病毒,噬斑滴定法检测灭活前后的病毒滴度,-干热法灭活脑心肌炎病毒(EMCV)和猪细小病毒(PPV),细胞病变法检测灭活前后的病毒滴度。结果:经S/D处理法灭活后,3批含S/D样品中辛德毕斯病毒降低量分别为>4.35 lg PFU·mL^(-1)、>4.51 lg PFU·mL^(-1)、>4.64 lg PFU·mL^(-1)。经干热法灭活后,3批不含S/D样品中EMCV降低量分别为≥5.38 lg TCID_(50)/0.1 mL、≥5.12 lg TCID_(50)/0.1 mL、≥5.25 lg TCID_(50)/0.1 mL,PPV降低量分别为4.57 lg TCID_(50)/0.1 mL、4.18 lg TCID_(50)/0.1 mL、4.68 lg TCID_(50)/0.1 mL。结论:通过对指示病毒的验证效果评估,证明S/D法和干热法对C1-INH中的辛德毕斯病毒、EMCV和PPV均有较好的灭活效果。
