目的:研究使用共培养系统将肌源性干细胞(MDSCs)诱导为神经元样细胞的可行性及机制.方法:分离新生SD大鼠的MDSCs及皮层神经元,以叔丁基过氧化氢(终浓度为200μmol/L)损伤神经元,构建氧化应激损伤的神经元模型.当MDSCs差速贴壁至第5代时,将其随机分为MDSCs和损伤的神经元置于共培养系统中培养(损伤组)、MDSCs和正常神经元共培养(未损伤组)以及MDSCs置于共培养系统中单独培养(MDSCs组),培养7d后用神经元特异性烯醇化酶(NSE)免疫细胞化学法鉴定诱导的结果,并用大鼠脑源性神经营养因子(BDNF) ELISA试剂盒检测不同时间点各组培养液中该因子的分泌情况.结果:共培养7d后检测到损伤组与未损伤组均有部分MDSCs分化为表达NSE的神经元样细胞,前者分化率高于后者,MDSCs组未见有细胞分化为神经元样细胞.第2天损伤组BDNF的分泌量高于未损伤组,同时,损伤组第2天BDNF的分泌量高于第4天和第6天的分泌量.在不同时间点损伤组与未损伤组培养液中BDNF的分泌量均高于MDSCs组.结论:在共培养条件下,大鼠皮层神经元可诱导MDSCs为神经元样细胞,这与神经元分泌的BDNF有着重要联系,MDSCs也可分泌BDNF.%Objective: To investigate the feasibility of transdifferentiation of muscle-derived stem cells (MDSCs) into neuronlike cells using a co-culture system. Methods: MDSCs and cortical neurons were isolated from newborn SD rats, and cultured, purified and identified. Oxidative stress neuronal damage model was induced by tert-butylhydroperoxide in vitro. The co-cultured cells were randomly divided into three groups. Injury group: tert-butylhydroperoxide treated group, the MDSCs of passage 5 were co-cultured with neurons which were treated with 200 μmol/L (final concentration) tert-butylhydroperoxide for 4 hours. Uninjury group: the MDSCs of passage 5 were co-cultured with normal neurons. MDSCs group: the MDSCs of passage 5 were incubated in both layers. Seven days later, the induced MDSCs were identified by neuron specific enolase (NSE). Secreted brain-derived neurotrophic factor (BDNF) in the supernatant was tested by ELISA. Results: Neuronlike cells (NSE-positive cells) were found in both the injury group and the uninjury group at 7 days of co-culture age. The ratio of NSE-positive cells in the injury group was significantly higher than that in the uninjury group (P＜ 0. 05). No NSEpositive cells were found in the MDSCs group. BDNF content in the supernatant was significantly higher in the injury group than that in the uninjury group (P＜ 0. 001) at 2 days of co-culture age. BDNF content was significantly higher in the uninjury group at 2 days of co-culture age than that in the injury group at 4 and 6 days of co-culture age (P＜0. 01). At the same time point, BDNF content in the MDSCs group was significantly lower than that in the injury group or uninjury group at the 2nd, 4th and 6th days (P＜ 0. 001). Conclusion: The newborn rat MDSCs have the potentiality of being transdifferentiated into neuron-like cells in a co-culture system. It is closely related with BDNF secreted by neurons. It is possible that MDSCs could secrete BDNF.
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