Mesenchymal stem cell(MSC)transplantation is a promising treatment strategy for spinal cord injury,but immunological rejection and possible tumor formation limit its application.The therapeutic effects of MSCs mainly ...Mesenchymal stem cell(MSC)transplantation is a promising treatment strategy for spinal cord injury,but immunological rejection and possible tumor formation limit its application.The therapeutic effects of MSCs mainly depend on their release of soluble paracrine factors.Exosomes are essential for the secretion of these paracrine effectors.Bone marrow mesenchymal stem cell-derived exosomes(BMSC-EXOs)can be substituted for BMSCs in cell transplantation.However,the underlying mechanisms remain unclear.In this study,a rat model of T10 spinal cord injury was established using the impact method.Then,30 minutes and 1 day after spinal cord injury,the rats were administered 200μL exosomes via the tail vein(200μg/mL;approximately 1×106 BMSCs).Treatment with BMSC-EXOs greatly reduced neuronal cell death,improved myelin arrangement and reduced myelin loss,increased pericyte/endothelial cell coverage on the vascular wall,decreased bloodspinal cord barrier leakage,reduced caspase 1 expression,inhibited interleukin-1βrelease,and accelerated locomotor functional recovery in rats with spinal cord injury.In the cell culture experiment,pericytes were treated with interferon-γand tumor necrosis factor-α.Then,Lipofectamine 3000 was used to deliver lipopolysaccharide into the cells,and the cells were co-incubated with adenosine triphosphate to simulate injury in vitro.Pre-treatment with BMSC-EXOs for 8 hours greatly reduced pericyte pyroptosis and increased pericyte survival rate.These findings suggest that BMSC-EXOs may protect pericytes by inhibiting pyroptosis and by improving blood-spinal cord barrier integrity,thereby promoting the survival of neurons and the extension of nerve fibers,and ultimately improving motor function in rats with spinal cord injury.All protocols were conducted with the approval of the Animal Ethics Committee of Zhengzhou University on March 16,2019.展开更多
Background Pericytes,located on microvessels,help to maintain vascular stability and blood-brain barrier integrity.The influence of pericytes on microvessels after spinal cord injury （SCI） is less clear.Therefore,th...Background Pericytes,located on microvessels,help to maintain vascular stability and blood-brain barrier integrity.The influence of pericytes on microvessels after spinal cord injury （SCI） is less clear.Therefore,the aim of this study was to investigate whether pericytes took a protective effect on microvessels in melatonin-treated SCI.Methods C57BL/6 mice were randomly divided into three groups：sham group,SCI group,and melatonin group （n=27per group）.Functional recovery was evaluated using the Basso Mouse Scale.Motor neurons were observed using hematoxylin and eosin staining.Pericyte coverage was analyzed using immunofluorescence.Permeability of blood-spinal cord barrier （BSCB） was assessed by administration of Evan＇s Blue.Protein levels of occludin,aquaporin-4 （AQP4）,angiopoietin-1 （Ang1）,intercellular cell adhesion molecule-1 （ICAM-1）,Bcl-2,and Bax were determined using Western blotting.Mimicking the pathological conditions of SCI,melatonin-treated primary pericytes were subjected to oxygenglucose deprivation/reperfusion （OGD/R）.Secretion of Ang1 was analyzed using an enzyme-linked immunosorbent assay,and the expression of ICAM-1 was detected by immunofluorescence.Results Melatonin treatment improved locomotor functional outcome and rescued motor neurons.Pericyte coverage was significantly reduced after SCI; melatonin treatment alleviated the loss of pericyte coverage and rescued perfused microvessels 7 days after injury.The permeability of BSCB and loss of occludin were attenuated,and edema formation and upregulation of AQP4 were inhibited,after melatonin treatment.The expression of Ang1 and Bcl-2 was improved,while the expression of ICAM-1 and Bax was inhibited,in melatonin-treated SCl mice.Furthermore,the secretion of Ang1 was increased and the expression of ICAM-1 was inhibited in melatonin-treated pericytes after OGD/R.Conclusions Melatonin ameliorated the loss of blood vessels and disruption of BSCB to exert a protective effect on SCI,which might be mediated by increased p展开更多
Background Comeal neovascular leakage can lead to edema and secondary scarring. Previous studies have shown that pericytes play a key role in maturation of angiogenesis. The present studies investigate the relationshi...Background Comeal neovascular leakage can lead to edema and secondary scarring. Previous studies have shown that pericytes play a key role in maturation of angiogenesis. The present studies investigate the relationship between vascular permeability and pericyte coverage of endothelial cells in rat corneal neovascular induced by alkali bums. Methods Corneal neovascular vessels induced by alkali bums was performed in Sprague-Dawley rats. Corneas were excised on 1,2, 3, 5, 7 and 10 days after cauterization. The vascular permeability rate was measured by the Evans blue method. The microvessel pericyte coverage index （MPI） was applied to quantify the pericyte coverage through double immunofluorescent staining of frozen sections of corneas with CD31 as the endothelial and α-smooth muscle actin （α-SMA） as the pericyte markers. The correlation between permeability rate and MPI was analyzed. Pericyte coverage was confirmed ultrastructually using transmission electron microscopy. Results The vascular permeability rate was （1.14±0.17）, （0.24±0.08）, （0.29±0.16）, （0.14±0.10）, （0.09±0.06） and （0.05±0.04）μg· ml^-1 · mm^-2respectively on 1, 2, 3, 5, 7 and 10 days after cauterization. The MPI was 0, 16.07%, 11.95%, 43.84%, 73.97% and 86.21% respectively at the above mentioned time points. The correlation coefficient between MPI and the permeability rate was -0.943 （P=-0.005）. Conclusions Pericyte recruitment was significantly correlated with the permeability of comeal neovascularization induced by alkali bums in rats. Therapeutic strategies aiming at anti-leakage should be most effective if they promote pericytes proliferation in the course of corneal neovascularization.展开更多
基金supported by the National Natural Science Foundation of ChinaNo.U1604170(to YJJ)。
文摘Mesenchymal stem cell(MSC)transplantation is a promising treatment strategy for spinal cord injury,but immunological rejection and possible tumor formation limit its application.The therapeutic effects of MSCs mainly depend on their release of soluble paracrine factors.Exosomes are essential for the secretion of these paracrine effectors.Bone marrow mesenchymal stem cell-derived exosomes(BMSC-EXOs)can be substituted for BMSCs in cell transplantation.However,the underlying mechanisms remain unclear.In this study,a rat model of T10 spinal cord injury was established using the impact method.Then,30 minutes and 1 day after spinal cord injury,the rats were administered 200μL exosomes via the tail vein(200μg/mL;approximately 1×106 BMSCs).Treatment with BMSC-EXOs greatly reduced neuronal cell death,improved myelin arrangement and reduced myelin loss,increased pericyte/endothelial cell coverage on the vascular wall,decreased bloodspinal cord barrier leakage,reduced caspase 1 expression,inhibited interleukin-1βrelease,and accelerated locomotor functional recovery in rats with spinal cord injury.In the cell culture experiment,pericytes were treated with interferon-γand tumor necrosis factor-α.Then,Lipofectamine 3000 was used to deliver lipopolysaccharide into the cells,and the cells were co-incubated with adenosine triphosphate to simulate injury in vitro.Pre-treatment with BMSC-EXOs for 8 hours greatly reduced pericyte pyroptosis and increased pericyte survival rate.These findings suggest that BMSC-EXOs may protect pericytes by inhibiting pyroptosis and by improving blood-spinal cord barrier integrity,thereby promoting the survival of neurons and the extension of nerve fibers,and ultimately improving motor function in rats with spinal cord injury.All protocols were conducted with the approval of the Animal Ethics Committee of Zhengzhou University on March 16,2019.
文摘Background Pericytes,located on microvessels,help to maintain vascular stability and blood-brain barrier integrity.The influence of pericytes on microvessels after spinal cord injury （SCI） is less clear.Therefore,the aim of this study was to investigate whether pericytes took a protective effect on microvessels in melatonin-treated SCI.Methods C57BL/6 mice were randomly divided into three groups：sham group,SCI group,and melatonin group （n=27per group）.Functional recovery was evaluated using the Basso Mouse Scale.Motor neurons were observed using hematoxylin and eosin staining.Pericyte coverage was analyzed using immunofluorescence.Permeability of blood-spinal cord barrier （BSCB） was assessed by administration of Evan＇s Blue.Protein levels of occludin,aquaporin-4 （AQP4）,angiopoietin-1 （Ang1）,intercellular cell adhesion molecule-1 （ICAM-1）,Bcl-2,and Bax were determined using Western blotting.Mimicking the pathological conditions of SCI,melatonin-treated primary pericytes were subjected to oxygenglucose deprivation/reperfusion （OGD/R）.Secretion of Ang1 was analyzed using an enzyme-linked immunosorbent assay,and the expression of ICAM-1 was detected by immunofluorescence.Results Melatonin treatment improved locomotor functional outcome and rescued motor neurons.Pericyte coverage was significantly reduced after SCI; melatonin treatment alleviated the loss of pericyte coverage and rescued perfused microvessels 7 days after injury.The permeability of BSCB and loss of occludin were attenuated,and edema formation and upregulation of AQP4 were inhibited,after melatonin treatment.The expression of Ang1 and Bcl-2 was improved,while the expression of ICAM-1 and Bax was inhibited,in melatonin-treated SCl mice.Furthermore,the secretion of Ang1 was increased and the expression of ICAM-1 was inhibited in melatonin-treated pericytes after OGD/R.Conclusions Melatonin ameliorated the loss of blood vessels and disruption of BSCB to exert a protective effect on SCI,which might be mediated by increased p
基金National Science Fund for Distinguished Young Scholars(No.30225044)Fund for Innovative Research Groups of China (No. 30321004)Natural Science Foundation of Guangdong Province of China (No. 36652).
文摘Background Comeal neovascular leakage can lead to edema and secondary scarring. Previous studies have shown that pericytes play a key role in maturation of angiogenesis. The present studies investigate the relationship between vascular permeability and pericyte coverage of endothelial cells in rat corneal neovascular induced by alkali bums. Methods Corneal neovascular vessels induced by alkali bums was performed in Sprague-Dawley rats. Corneas were excised on 1,2, 3, 5, 7 and 10 days after cauterization. The vascular permeability rate was measured by the Evans blue method. The microvessel pericyte coverage index （MPI） was applied to quantify the pericyte coverage through double immunofluorescent staining of frozen sections of corneas with CD31 as the endothelial and α-smooth muscle actin （α-SMA） as the pericyte markers. The correlation between permeability rate and MPI was analyzed. Pericyte coverage was confirmed ultrastructually using transmission electron microscopy. Results The vascular permeability rate was （1.14±0.17）, （0.24±0.08）, （0.29±0.16）, （0.14±0.10）, （0.09±0.06） and （0.05±0.04）μg· ml^-1 · mm^-2respectively on 1, 2, 3, 5, 7 and 10 days after cauterization. The MPI was 0, 16.07%, 11.95%, 43.84%, 73.97% and 86.21% respectively at the above mentioned time points. The correlation coefficient between MPI and the permeability rate was -0.943 （P=-0.005）. Conclusions Pericyte recruitment was significantly correlated with the permeability of comeal neovascularization induced by alkali bums in rats. Therapeutic strategies aiming at anti-leakage should be most effective if they promote pericytes proliferation in the course of corneal neovascularization.
