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
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
In space,surface tension plays an important role and liquid behaviour is much different from that on the ground.The static capillary surfaces in the annular space between two coaxial cones under microgravity are studi...In space,surface tension plays an important role and liquid behaviour is much different from that on the ground.The static capillary surfaces in the annular space between two coaxial cones under microgravity are studied in this paper.Theoretical expressions of the capillary surfaces are derived and a procedure is developed to predict the capillary surfaces based on the expressions.By considering various liquid contact angles,liquid volumes,and container geometries,numerical simulation with the volume of fluid method is carried out and microgravity experiments in Beijing Drop Tower are performed.The numerical and experimental results are in good agreement with theoretical predictions.Furthermore,capillary surfaces in an annulus with constant cross-section and in a spherical tank with a central column are also discussed.z3 will decrease obviously with the increase of the liquid contact angle.The theoretical models and findings will be great helpful for liquid management in space and the evaluation of propellant residue.展开更多
Objective In this study,we analyzed the transcriptome sequences of Kupffer cells exposed to simulated microgravity for 3 d and conducted biological experiments to determine how microgravity initiates apoptosis in Kupf...Objective In this study,we analyzed the transcriptome sequences of Kupffer cells exposed to simulated microgravity for 3 d and conducted biological experiments to determine how microgravity initiates apoptosis in Kupffer cells.Methods Rotary cell culture system was used to construct a simulated microgravity model.GO and KEGG analyses were conducted using the DAVID database.GSEA was performed using the R language.The STRING database was used to conduct PPI analysis.qPCR was used to measure the IL1B,TNFA,CASP3,CASP9,and BCL2L11 mRNA expressions.Western Blotting was performed to detect the level of proteins CASP3 and CASP 9.Flow cytometry was used to detect apoptosis and mitochondrial membrane cells.Transmission electron microscopy was used to detect changes in the ultrastructure of Kupffer cells.Results Transcriptome Sequencing indicated that simulated microgravity affected apoptosis and the inflammatory state of Kupffer cells.Simulated microgravity improved the CASP3,CASP9,and BCL2L11 expressions in Kupffer cells.Annexin-V/PI and JC-1 assays showed that simulated microgravity promoted apoptosis in Kupffer cells.Simulated microgravity causes M1 polarization in Kupffer cells.Conclusion Our study found that simulated microgravity facilitated the apoptosis of Kupffer cells through the mitochondrial pathway and activated Kupffer cells into M1 polarization,which can secrete TNFA to promote apoptosis.展开更多
背景:在微重力环境中骨吸收和骨形成的失衡,导致航天员出现严重的骨质流失。现有研究表明,微重力环境下的骨质流失是由多种细胞、组织和系统共同作用的结果。目的:综述微重力对不同的细胞、组织或系统产生不同的生物学效应,总结微重力...背景:在微重力环境中骨吸收和骨形成的失衡,导致航天员出现严重的骨质流失。现有研究表明,微重力环境下的骨质流失是由多种细胞、组织和系统共同作用的结果。目的:综述微重力对不同的细胞、组织或系统产生不同的生物学效应,总结微重力导致骨质疏松发生的机制。方法:在Pub Med、Web of Science和Cochrane图书馆数据库检索2000-2023年的相关文献,纳入标准为与微重力导致骨质疏松相关的组织工程研究和基础研究的所有文章,最终对85篇文献进行综述。结果与结论:(1)在微重力环境下,骨髓间充质干细胞更倾向于向成脂细胞分化,减少向成骨细胞分化,而微重力环境中的造血干细胞则更倾向于分化为破骨细胞,减少向红系分化;同时,微重力抑制成骨细胞增殖和分化、促进成骨细胞凋亡、改变细胞形态及降低成骨细胞矿化能力,显著增加破骨细胞数量和活性并且阻碍成骨细胞向骨细胞分化,促进骨细胞的凋亡。(2)在微重力环境下,人体会出现骨骼肌萎缩、微血管重塑、骨微循环障碍及内分泌紊乱等组织或系统的变化,这些变化会导致骨骼微环境下机械应力卸载,血液灌注不足以及钙循环紊乱等,对骨质疏松的发生产生了重要的影响。(3)目前,微重力导致骨质疏松的机制较为复杂,通过更深入的研究这些生理机制对于确保航天员在长期太空任务中的健康至关重要,并为预防和治疗骨质疏松症提供了理论依据。展开更多
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.
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.
基金supported by the China Manned Space Engineering Program(Fluid Physics Experimental Rack and the Priority Research Program of Space Station)the Natural Science Foundation Project(Grant No.12032020).
文摘In space,surface tension plays an important role and liquid behaviour is much different from that on the ground.The static capillary surfaces in the annular space between two coaxial cones under microgravity are studied in this paper.Theoretical expressions of the capillary surfaces are derived and a procedure is developed to predict the capillary surfaces based on the expressions.By considering various liquid contact angles,liquid volumes,and container geometries,numerical simulation with the volume of fluid method is carried out and microgravity experiments in Beijing Drop Tower are performed.The numerical and experimental results are in good agreement with theoretical predictions.Furthermore,capillary surfaces in an annulus with constant cross-section and in a spherical tank with a central column are also discussed.z3 will decrease obviously with the increase of the liquid contact angle.The theoretical models and findings will be great helpful for liquid management in space and the evaluation of propellant residue.
文摘Objective In this study,we analyzed the transcriptome sequences of Kupffer cells exposed to simulated microgravity for 3 d and conducted biological experiments to determine how microgravity initiates apoptosis in Kupffer cells.Methods Rotary cell culture system was used to construct a simulated microgravity model.GO and KEGG analyses were conducted using the DAVID database.GSEA was performed using the R language.The STRING database was used to conduct PPI analysis.qPCR was used to measure the IL1B,TNFA,CASP3,CASP9,and BCL2L11 mRNA expressions.Western Blotting was performed to detect the level of proteins CASP3 and CASP 9.Flow cytometry was used to detect apoptosis and mitochondrial membrane cells.Transmission electron microscopy was used to detect changes in the ultrastructure of Kupffer cells.Results Transcriptome Sequencing indicated that simulated microgravity affected apoptosis and the inflammatory state of Kupffer cells.Simulated microgravity improved the CASP3,CASP9,and BCL2L11 expressions in Kupffer cells.Annexin-V/PI and JC-1 assays showed that simulated microgravity promoted apoptosis in Kupffer cells.Simulated microgravity causes M1 polarization in Kupffer cells.Conclusion Our study found that simulated microgravity facilitated the apoptosis of Kupffer cells through the mitochondrial pathway and activated Kupffer cells into M1 polarization,which can secrete TNFA to promote apoptosis.
文摘背景:在微重力环境中骨吸收和骨形成的失衡,导致航天员出现严重的骨质流失。现有研究表明,微重力环境下的骨质流失是由多种细胞、组织和系统共同作用的结果。目的:综述微重力对不同的细胞、组织或系统产生不同的生物学效应,总结微重力导致骨质疏松发生的机制。方法:在Pub Med、Web of Science和Cochrane图书馆数据库检索2000-2023年的相关文献,纳入标准为与微重力导致骨质疏松相关的组织工程研究和基础研究的所有文章,最终对85篇文献进行综述。结果与结论:(1)在微重力环境下,骨髓间充质干细胞更倾向于向成脂细胞分化,减少向成骨细胞分化,而微重力环境中的造血干细胞则更倾向于分化为破骨细胞,减少向红系分化;同时,微重力抑制成骨细胞增殖和分化、促进成骨细胞凋亡、改变细胞形态及降低成骨细胞矿化能力,显著增加破骨细胞数量和活性并且阻碍成骨细胞向骨细胞分化,促进骨细胞的凋亡。(2)在微重力环境下,人体会出现骨骼肌萎缩、微血管重塑、骨微循环障碍及内分泌紊乱等组织或系统的变化,这些变化会导致骨骼微环境下机械应力卸载,血液灌注不足以及钙循环紊乱等,对骨质疏松的发生产生了重要的影响。(3)目前,微重力导致骨质疏松的机制较为复杂,通过更深入的研究这些生理机制对于确保航天员在长期太空任务中的健康至关重要,并为预防和治疗骨质疏松症提供了理论依据。
