Dear Editor,As space exploration transitions from short orbital missions to extended stays on the International Space Station(ISS)and,ultimately,interplanetary travel,astronaut health has emerged as a critical focus.I...Dear Editor,As space exploration transitions from short orbital missions to extended stays on the International Space Station(ISS)and,ultimately,interplanetary travel,astronaut health has emerged as a critical focus.In particular,safeguarding cardiovascular function has become an operational imperative.Yet beyond safeguarding those in orbit,the physiological adaptations observed in microgravity offer a compelling lens through which to examine persistent challenges in terrestrial medicine,from orthostatic intolerance in the elderly to deconditioning in critical care survivors.By studying how the human cardiovascular system functions in the absence of gravity.展开更多
BACKGROUND Simulated microgravity environment can lead to gastrointestinal motility disturbance.The pathogenesis of gastrointestinal motility disorders is closely related to the stem cell factor(SCF)/c-kit signaling p...BACKGROUND Simulated microgravity environment can lead to gastrointestinal motility disturbance.The pathogenesis of gastrointestinal motility disorders is closely related to the stem cell factor(SCF)/c-kit signaling pathway associated with intestinal flora and Cajal stromal cells.Moreover,intestinal flora can also affect the regulation of SCF/c-kit signaling pathway,thus affecting the expression of Cajal stromal cells.Cajal cells are the pacemakers of gastrointestinal motility.AIM To investigate the effects of Bifidobacterium lactis(B.lactis)BLa80 on the intestinal flora of rats in simulated microgravity and on the gastrointestinal motility-related SCF/c-kit pathway.METHODS The internationally recognized tail suspension animal model was used to simulate the microgravity environment,and 30 rats were randomly divided into control group,tail suspension group and drug administration tail suspension group with 10 rats in each group for a total of 28 days.The tail group was given B.lactis BLa80 by intragastric administration,and the other two groups were given water intragastric administration,the concentration of intragastric administration was 0.1 g/mL,and each rat was 1 mL/day.Hematoxylin&eosin staining was used to observe the histopathological changes in each segment of the intestine of each group,and the expression levels of SCF,c-kit,extracellular signal-regulated kinase(ERK)and p-ERK in the gastric antrum of each group were detected by Western blotting and PCR.The fecal flora and mucosal flora of rats in each group were detected by 16S rRNA.RESULTS Simulated microgravity resulted in severe exfoliation of villi of duodenum,jejunum and ileum in rats,marked damage,increased space between villi,loose arrangement,shortened columnar epithelium of colon,less folds,narrower mucosal thickness,reduced goblet cell number and crypts,and significant improvement after probiotic intervention.Simulated microgravity reduced the expressions of SCF and c-kit,and increased the expressions of ERK and P-ERK in the gastric antrum of rats.However,after probiotic intervention,the expressions of SCF and ckit were increased,while the expressions of ERK and P-ERK were decreased,with statistical significance(P<0.05).In addition,simulated microgravity can reduce the operational taxonomic unit(OTU)of the overall intestinal flora of rats,B.lactis BLa80 can increase the OTU of rats,simulated microgravity can reduce the overall richness and diversity of stool flora of rats,increase the abundance of firmicutes in stool flora of rats,and reduce the abundance of Bacteroides in stool flora of rats,most of which are mainly beneficial bacteria.Simulated microgravity can increase the overall richness and diversity of mucosal flora,increase the abundance of Bacteroides and Desulphurides in the rat mucosal flora,and decrease the abundance of firmicutes,most of which are proteobacteria.After probiotics intervention,the overall Bacteroidetes trend in simulated microgravity rats was increased.CONCLUSION B.lactis BLa80 can ameliorate intestinal mucosal injury,regulate intestinal flora,inhibit ERK expression,and activate the SCF/c-kit signaling pathway,which may have a facilitating effect on gastrointestinal motility in simulated microgravity rats.展开更多
The ongoing advancement of aerospace technology globally offers technical support for human exploration of outer space.Nevertheless,astronauts encounter microgravity environments during their missions in outer space,w...The ongoing advancement of aerospace technology globally offers technical support for human exploration of outer space.Nevertheless,astronauts encounter microgravity environments during their missions in outer space,which significantly affects the functionality of various physiological systems,including the skeletal,muscular and immune systems.Among them,microgravity-induced bone loss is particularly severe.Bone loss markedly elevates the risk of osteoporosis and fractures,presenting a substantial obstacle to astronauts’ability to perform tasks in the space environment and maintain their physical health.Consequently,implementing scientifically grounded preventive and therapeutic measures is essential for mitigating microgravity-induced bone loss.Currently,numerous intervention strategies have been demonstrated to effectively address microgravity-induced bone loss,such as pharmacological treatment,nutritional supplementation,and exercise intervention.However,the efficacy of these interventions varies,and some may result in adverse effects.Therefore,this narrative review analyzes and summarizes the effects of various interventions on bone loss caused by microgravity,aiming to provide a scientific theoretical basis for determining the optimal intervention strategy.展开更多
AIM:To analyze visual dysfunction in rats under simulated weightlessness(SW)by examining trans-laminar cribrosa pressure difference(TLCPD)and neuroimmune responses.METHODS:The 72 male Sprague-Dawley rats were randomly...AIM:To analyze visual dysfunction in rats under simulated weightlessness(SW)by examining trans-laminar cribrosa pressure difference(TLCPD)and neuroimmune responses.METHODS:The 72 male Sprague-Dawley rats were randomly assigned into two groups(ground control and hindlimb unloading-simulated microgravity)using stratified randomization,with each group further subdivided into three exposure durations:SW 2-week(SW-2W),4-week(SW-4W),and 8-week(SW-8W),n=12 per subgroup.At the designated time points for each group,intraocular pressure(IOP)and intracranial pressure(ICP)were measured,and the trans-laminar cribrosa pressure difference(TLCPD)was calculated.Additionally,optomotor response(OMR),electroretinography(ERG),and optical coherence tomography(OCT)were performed.The number of retinal ganglion cells(RGCs)was quantified via immunofluorescence,the activation of astrocytes and microglial cells was determined,and Sholl analysis was conducted to assess the function and morphology of microglial cells.Data were analyzed with SPSS and GraphPad Prism(P<0.05).RESULTS:Under prolonged simulated microgravity,rats exhibited a progressive increase in both IOP and ICP,with the most pronounced rise observed at 8wk.Concurrently,the TLCPD shifted from a negative value in controls to a positive value.These pressure alterations were associated with retinal dysfunction,as evidenced by significant reductions in ERG b-wave and photopic negative response(PhNR)amplitudes.OCT and histological analyses revealed subtle photoreceptor layer damage:while the inner nuclear layer(INL)thickness remained relatively unchanged,the outer nuclear layer(ONL)thinned significantly,and the nerve fiber layer-ganglion cell layer complex thickness(NFL-GCL)complex initially thickened before later thinning.Immunofluorescence further demonstrated marked neuroimmune activation,with astrocytes transitioning from having large cell bodies with small,elongated,sparse processes to a phenotype characterized by compact,enlarged nuclei and aggregated processes,alongside notable RGC loss.CONCLUSION:Based on the results from the simulated microgravity rat model,microgravity-induced changes in dual-chamber pressure,and neuroimmune responses in the retina may play a key role in visual dysfunction.Specifically,the activation of retinal neuroimmune cells(astrocytes and microglial cells)induced by mechanical stress appears to be central to retinal and optic nerve damage.展开更多
Underground gas storage(UGS)are an important guarantee for national energy strategic reserves,but the monitoring of gas reservoir distribution has always faced challenges.Time-lapse microgravity monitoring technology ...Underground gas storage(UGS)are an important guarantee for national energy strategic reserves,but the monitoring of gas reservoir distribution has always faced challenges.Time-lapse microgravity monitoring technology can infer the movement patterns of substances based on density changes at different times.Simulation results indicate that this technology provides strong support for the dynamic monitoring of UGS.However,in the process of processing time-lapse microgravity data,it is necessary to use field separation technology to obtain the gravity anomaly of the target body.In order to obtain more accurate and stable field separation results,this paper utilizes the low-rank nature of the regional field and the sparsity of the local field in potential field data,and adopts a method based on Robust Principal Component Analysis(RPCA)for field separation processing.In the study of the gas injection process in the Y21 UGS,microgravity measurement and processing results show that the areas with enriched natural gas in the UGS are approximately annular and located in the structural high-point areas,which basically match the geological structural characteristics.Due to the presence of boundary faults,according to the results of time-lapse microgravity,it is inferred that groundwater moves towards the structural high-point areas,and natural gas mainly moves towards the southwest direction,providing the direction of underground fluid movement during the gas injection process in the UGS.展开更多
文摘Dear Editor,As space exploration transitions from short orbital missions to extended stays on the International Space Station(ISS)and,ultimately,interplanetary travel,astronaut health has emerged as a critical focus.In particular,safeguarding cardiovascular function has become an operational imperative.Yet beyond safeguarding those in orbit,the physiological adaptations observed in microgravity offer a compelling lens through which to examine persistent challenges in terrestrial medicine,from orthostatic intolerance in the elderly to deconditioning in critical care survivors.By studying how the human cardiovascular system functions in the absence of gravity.
文摘BACKGROUND Simulated microgravity environment can lead to gastrointestinal motility disturbance.The pathogenesis of gastrointestinal motility disorders is closely related to the stem cell factor(SCF)/c-kit signaling pathway associated with intestinal flora and Cajal stromal cells.Moreover,intestinal flora can also affect the regulation of SCF/c-kit signaling pathway,thus affecting the expression of Cajal stromal cells.Cajal cells are the pacemakers of gastrointestinal motility.AIM To investigate the effects of Bifidobacterium lactis(B.lactis)BLa80 on the intestinal flora of rats in simulated microgravity and on the gastrointestinal motility-related SCF/c-kit pathway.METHODS The internationally recognized tail suspension animal model was used to simulate the microgravity environment,and 30 rats were randomly divided into control group,tail suspension group and drug administration tail suspension group with 10 rats in each group for a total of 28 days.The tail group was given B.lactis BLa80 by intragastric administration,and the other two groups were given water intragastric administration,the concentration of intragastric administration was 0.1 g/mL,and each rat was 1 mL/day.Hematoxylin&eosin staining was used to observe the histopathological changes in each segment of the intestine of each group,and the expression levels of SCF,c-kit,extracellular signal-regulated kinase(ERK)and p-ERK in the gastric antrum of each group were detected by Western blotting and PCR.The fecal flora and mucosal flora of rats in each group were detected by 16S rRNA.RESULTS Simulated microgravity resulted in severe exfoliation of villi of duodenum,jejunum and ileum in rats,marked damage,increased space between villi,loose arrangement,shortened columnar epithelium of colon,less folds,narrower mucosal thickness,reduced goblet cell number and crypts,and significant improvement after probiotic intervention.Simulated microgravity reduced the expressions of SCF and c-kit,and increased the expressions of ERK and P-ERK in the gastric antrum of rats.However,after probiotic intervention,the expressions of SCF and ckit were increased,while the expressions of ERK and P-ERK were decreased,with statistical significance(P<0.05).In addition,simulated microgravity can reduce the operational taxonomic unit(OTU)of the overall intestinal flora of rats,B.lactis BLa80 can increase the OTU of rats,simulated microgravity can reduce the overall richness and diversity of stool flora of rats,increase the abundance of firmicutes in stool flora of rats,and reduce the abundance of Bacteroides in stool flora of rats,most of which are mainly beneficial bacteria.Simulated microgravity can increase the overall richness and diversity of mucosal flora,increase the abundance of Bacteroides and Desulphurides in the rat mucosal flora,and decrease the abundance of firmicutes,most of which are proteobacteria.After probiotics intervention,the overall Bacteroidetes trend in simulated microgravity rats was increased.CONCLUSION B.lactis BLa80 can ameliorate intestinal mucosal injury,regulate intestinal flora,inhibit ERK expression,and activate the SCF/c-kit signaling pathway,which may have a facilitating effect on gastrointestinal motility in simulated microgravity rats.
基金the National Natural Science Foundation of China(No.81901430)the Guangdong Basic and Applied Basic Research Foundation(No.2022A1515010379)+3 种基金the Guangdong Philosophy and Social Science Foundation Regular Project(GD23YTY04)the Special Projects in Key Fields of Ordinary Universities in Guangdong Province(No.2024ZDZX2059)the Guangdong Province General University Innovation Team Project(2023WCXTD011)the Guangdong Provincial Key Laboratory of Physical Activity and Health Promotion(2021B1212040014).
文摘The ongoing advancement of aerospace technology globally offers technical support for human exploration of outer space.Nevertheless,astronauts encounter microgravity environments during their missions in outer space,which significantly affects the functionality of various physiological systems,including the skeletal,muscular and immune systems.Among them,microgravity-induced bone loss is particularly severe.Bone loss markedly elevates the risk of osteoporosis and fractures,presenting a substantial obstacle to astronauts’ability to perform tasks in the space environment and maintain their physical health.Consequently,implementing scientifically grounded preventive and therapeutic measures is essential for mitigating microgravity-induced bone loss.Currently,numerous intervention strategies have been demonstrated to effectively address microgravity-induced bone loss,such as pharmacological treatment,nutritional supplementation,and exercise intervention.However,the efficacy of these interventions varies,and some may result in adverse effects.Therefore,this narrative review analyzes and summarizes the effects of various interventions on bone loss caused by microgravity,aiming to provide a scientific theoretical basis for determining the optimal intervention strategy.
文摘AIM:To analyze visual dysfunction in rats under simulated weightlessness(SW)by examining trans-laminar cribrosa pressure difference(TLCPD)and neuroimmune responses.METHODS:The 72 male Sprague-Dawley rats were randomly assigned into two groups(ground control and hindlimb unloading-simulated microgravity)using stratified randomization,with each group further subdivided into three exposure durations:SW 2-week(SW-2W),4-week(SW-4W),and 8-week(SW-8W),n=12 per subgroup.At the designated time points for each group,intraocular pressure(IOP)and intracranial pressure(ICP)were measured,and the trans-laminar cribrosa pressure difference(TLCPD)was calculated.Additionally,optomotor response(OMR),electroretinography(ERG),and optical coherence tomography(OCT)were performed.The number of retinal ganglion cells(RGCs)was quantified via immunofluorescence,the activation of astrocytes and microglial cells was determined,and Sholl analysis was conducted to assess the function and morphology of microglial cells.Data were analyzed with SPSS and GraphPad Prism(P<0.05).RESULTS:Under prolonged simulated microgravity,rats exhibited a progressive increase in both IOP and ICP,with the most pronounced rise observed at 8wk.Concurrently,the TLCPD shifted from a negative value in controls to a positive value.These pressure alterations were associated with retinal dysfunction,as evidenced by significant reductions in ERG b-wave and photopic negative response(PhNR)amplitudes.OCT and histological analyses revealed subtle photoreceptor layer damage:while the inner nuclear layer(INL)thickness remained relatively unchanged,the outer nuclear layer(ONL)thinned significantly,and the nerve fiber layer-ganglion cell layer complex thickness(NFL-GCL)complex initially thickened before later thinning.Immunofluorescence further demonstrated marked neuroimmune activation,with astrocytes transitioning from having large cell bodies with small,elongated,sparse processes to a phenotype characterized by compact,enlarged nuclei and aggregated processes,alongside notable RGC loss.CONCLUSION:Based on the results from the simulated microgravity rat model,microgravity-induced changes in dual-chamber pressure,and neuroimmune responses in the retina may play a key role in visual dysfunction.Specifically,the activation of retinal neuroimmune cells(astrocytes and microglial cells)induced by mechanical stress appears to be central to retinal and optic nerve damage.
基金supported by Project funded by Projects of Sinopec(P25115).
文摘Underground gas storage(UGS)are an important guarantee for national energy strategic reserves,but the monitoring of gas reservoir distribution has always faced challenges.Time-lapse microgravity monitoring technology can infer the movement patterns of substances based on density changes at different times.Simulation results indicate that this technology provides strong support for the dynamic monitoring of UGS.However,in the process of processing time-lapse microgravity data,it is necessary to use field separation technology to obtain the gravity anomaly of the target body.In order to obtain more accurate and stable field separation results,this paper utilizes the low-rank nature of the regional field and the sparsity of the local field in potential field data,and adopts a method based on Robust Principal Component Analysis(RPCA)for field separation processing.In the study of the gas injection process in the Y21 UGS,microgravity measurement and processing results show that the areas with enriched natural gas in the UGS are approximately annular and located in the structural high-point areas,which basically match the geological structural characteristics.Due to the presence of boundary faults,according to the results of time-lapse microgravity,it is inferred that groundwater moves towards the structural high-point areas,and natural gas mainly moves towards the southwest direction,providing the direction of underground fluid movement during the gas injection process in the UGS.
