神经干细胞移植影响脊髓全横断大鼠大脑运动皮质相关凋亡基因的表达

背景:多项研究已证实神经干细胞能促进脊髓损伤大鼠神经功能的恢复,但其分子机制还不清楚.目的:观察神经干细胞移植对脊髓全横断损伤大鼠大脑运动皮质相关凋亡基因Bax,Bcl-2和Caspase-3 mRNA表达的影响.设计、时间及地点:随机对照动物实验,于2007-07/2008-12在昆明医学院神经科学研究所完成.材料:孕14-15 d绿色荧光蛋白转基因鼠5只,取其胚胎用于神经干细胞培养.清洁级健康成年雌性SD大鼠88只,随机分成3组:假手术组8只、模型组40只、细胞移植组40只.方法:模型组、细胞移植组大鼠建立T_9脊髓全横断脊髓损伤模型,假手术组只行T_8椎板切除.用DMEM/F12调整胎鼠神经干细胞密度为2×10~(10)L~(-1),吸取细胞悬液15 μL滴加到约2 mm~3大小的明胶薄片上,细胞移植组将此明胶薄片植入大鼠脊髓两横断面之间的间隙处.分别于细胞移植后3,7,14,21,28 d取材进行指标检测.主要观察指标:RT-PCR法检测大脑运动皮质Bax,Bcl-2和Caspase-3 mRNA表达的变化.结果:与假手术组比较,模型组各时间点Bax的表达均无明显差异(P>0.05),术后14,28 d Bcl-2的表达明显减少(P<0.05),术后3 d Caspase-3的表达明显升高(P<0.05).与模型组比较,细胞移植组在神经干细胞移植后3 d Bax的表达明显减少(P<0.05),移植后14,21 d Bcl-2的表达明显增高(P

Effects of neural stem cells transplantation on apoptosis-related genes expression in the motor cortex of rats subjected to spinal cord transection

BACKGROUND: Many studies showed that neural stem cells (NSC) transplantation can promote functional improvements in rats subjected to spinal cord injury. However, the underlying molecular mechanisms remain poorly understood.OBJECTIVE: To observe the effects of NSC transplantation on expressions of Bax, Bcl-2 and Caspase-3 in the motor cortex in rats subjected to spinal cord transection.DESIGN, TIME AND SETTING: The randomized controlled animal experiment was performed at Institute of Neuroscience,Kunming Medical College from July 2007 to December 2008.MATERIALS: Five green fluorescent protein transgenic mice with 14-15 embryonic days were prepared for NSC. Additionally 88 adult female Sprague-Dawley (SD) rats were randomly divided into sham operation group (n=8), model group (n=40) and NSC transplantation group (n=40).METHODS: Model of spinal cord transection was established by cut transversely Sprague-Dawley (SD) rats T_9 segment. Rats in the sham operation group were subjected to laminectomy at T_8, without spinal cord injury. After the spinal cord was exposed at the lesion site, a small piece of 2 mm~3 gel foam soaked with 3×10~5 NSC were implanted into the gap to fill the lesion site of the T_9 level in rats of the NSC transplantation group. The measurements of relative indexes were performed at the days 3, 7,14, 21 and 28 after transplantation.MAIN OUTCOME MEASURES: Changes of Bax, Bcl-2 and Caspase-3 expressions were detected by RT-PCR.RESULTS: Compared to the sham operation group, the Bax expression in the model group had no significant difference (P >0.05), the expression of Bcl-2 was decreased obviously at days 14 and 28 after operation (P < 0.05), while a significant increase on the expression of Caspase-3 at day 3 (P < 0.05). Compared to the model group, the expression of Bax was dramatically decreased in the NSC transplantation group at day 3 (P < 0.05), with a notably increased Bcl-2 expression at days 14 and 21 after transplantation (P < 0.05), but the expression of Caspase-3 presented a significant decrease at days 3 and 7 after transplantation (P < 0.05).CONCLUSION: NSC transplantation probably regulates the expression of apoptosis genes (Bax, Bcl-2 and Caspase-3 mRNA) to promote neurological function recovery in rats subjected to cord transection.