Human cranial bone-derived mesenchymal stem cells cultured under microgravity can improve cerebral infarction in rats

Transplantation of human cranial bone-derived mesenchymal stem cells (hcMSCs) in central nervous system disorders has the potential to improve motor function by highly expressing neurotrophic factors. However, the effects of hcMSCs cultured under microgravity (MG) conditions on cerebral infarction have not been investigated before. Thus, this study aimed to investigate the transplantation effects of hcMSCs cultured in a simulated MG environment on cerebral infarction model rats. Our results showed that neurological function was significantly improved after transplantation of hcMSCs cultured in the MG environment (MG group) compared with normal gravity environment (1G group). Protein expressions of nerve growth factor, fibroblast growth factor 2, and synaptophysin were significantly higher in the MG group than in the IG group, whereas sortilin 1 expression was significantly lower. MicroRNA analysis revealed that genes related to cell proliferation, angiogenesis, neurotrophy, anti-apoptosis, neural and synaptic organization, and cell differentiation inhibition were significantly upregulated in the MG group. In contrast, genes promoting microtubule and extracellular matrix formation and cell adhesion, signaling, and differentiation were downregulated. These results indicate that hcMSCs cultured in an MG environment may be a useful source of stem cells for recovery of neurological function after cerebral infarction. Cerebral infarction model rats were generated; hcMSCs cultured in normal gravity (1G) or MG environment were transplanted via the transvenous route on the first day after induction of cerebral infarction for immunohistological analysis and neurological function evaluation. The expression of endogenous neurotrophic factors, axonal, neuronal, and synaptogenic factors, angiogenic factors, and apoptosis-related factors in infarcted brain tissue at 35 days after stroke induction was examined by real-time polymerase chain reaction (PCR) and western blotting analyses. Sequencing analysis of miRNAs was performed in hcMSCs cultured under 1G or MG environments.

人颅骨来源间充质干细胞（human cranial bone-derived mesenchymal stem cells, hcMSCs）移植用于中枢神经系统疾病（central nervous system disorders）时，可通过高表达神经营养因子（neurotrophic factors）改善运动功能。然而，目前尚未有研究探讨微重力（microgravity, MG）环境下培养的hcMSCs对脑梗死（cerebral infarction）的作用。鉴于此，本研究旨在探讨模拟微重力环境下培养的hcMSCs移植对脑梗死模型大鼠的影响。本研究结果显示，与正常重力（normal gravity, 1G）组相比，微重力环境培养的hcMSCs移植组（MG组）大鼠的神经功能（neurological function）得到显著改善。MG组的神经生长因子（nerve growth factor）、成纤维细胞生长因子2（fibroblast growth factor 2, FGF2）及突触素（synaptophysin）的蛋白表达水平显著高于1G组，而分选蛋白1（sortilin 1）的表达水平则显著降低。微小RNA（microRNA, miRNA）分析结果表明，MG组中与细胞增殖（cell proliferation）、血管生成（angiogenesis）、神经营养、抗凋亡、神经与突触组织构建及细胞分化抑制相关的基因均显著上调。与之相反，促进微管（microtubule）与细胞外基质（extracellular matrix）形成、细胞黏附（cell adhesion）、信号传导（signaling）及细胞分化（cell differentiation）的基因则显著下调。上述结果表明，经模拟微重力环境培养的hcMSCs或可成为脑梗死后神经功能修复的理想干细胞来源。本研究构建了脑梗死模型大鼠，于脑梗死诱导后第1天经静脉途径移植正常重力（1G）或微重力（MG）环境培养的hcMSCs，用于免疫组织化学分析（immunohistological analysis）与神经功能评估。本研究通过实时聚合酶链反应（real-time polymerase chain reaction, PCR）及蛋白质印迹法（western blotting）分析，检测了脑梗死诱导后35天时梗死脑组织中内源性神经营养因子、轴突、神经元及突触生成因子、血管生成因子与凋亡相关因子的表达水平。此外，本研究对1G或MG环境下培养的hcMSCs进行了miRNA测序分析。