人脐血间充质干细胞移植脑梗死大鼠神经功能的恢复及脑组织端粒酶反转录酶表达

Effects of umbilical cord blood-derived mesenchymal stem cell transplantation on recovery of nerve function and telomerase reverse transcriptase expression in brain tissue of cerebral infarction rats

背景:脐血间充质干细胞可以经体循环有效穿透室管膜进入脑组织,迁移至脑损伤区域并存活分化为神经细胞,作为替代细胞来源用于中枢神经系统疾病的治疗。目的:探讨人脐血间充质干细胞移植对脑梗死大鼠神经功能恢复及脑组织端粒酶反转录酶表达的影响。方法:选取130只大鼠为研究对象,随机分为对照组(30只)、模型组(30只)、脐血间充质干细胞1组(35只)、脐血间充质干细胞2组(35只);对照组不做任何处理,其余各组采用颈内动脉线栓法制作脑梗死大鼠模型,脐血间充质干细胞1,2组于造模成功后1,4 d尾静脉移植2×106个脐血间充质干细胞;移植后24 h检测大鼠血清中活性氧和超氧化物歧化酶水平,移植后第7,14天进行Y-迷宫实验和神经功能评分,采用TUNEL法检测病灶中心神经细胞凋亡率,Western blot法检测梗死灶周围Caspase-3、Bax、Bcl-2、端粒酶反转录酶蛋白表达,RT-PCR法检测梗死灶周围端粒酶反转录酶的mRNA表达。结果与结论:①与对照组相比,模型组大鼠Y-迷宫实验错误次数、神经功能评分、细胞凋亡指数、Caspase-3、Bax蛋白表达、活性氧水平均显著升高(P<0.05),Bcl-2、端粒酶反转录酶蛋白以及mRNA表达、超氧化物歧化酶水平均显著降低(P<0.05);②与模型组相比,脐血间充质干细胞1组和脐血间充质干细胞2组大鼠Y-迷宫实验错误次数、神经功能评分、细胞凋亡指数、Caspase-3、Bax蛋白表达、活性氧水平均显著降低(P<0.05),Bcl-2、端粒酶反转录酶蛋白以及mRNA表达、超氧化物歧化酶水平均显著升高(P<0.05);③与脐血间充质干细胞2组相比,脐血间充质干细胞1组大鼠Y-迷宫实验错误次数、神经功能评分、细胞凋亡指数、Caspase-3、Bax蛋白表达、活性氧水平均显著降低(P<0.05),Bcl-2、端粒酶反转录酶蛋白以及mRNA表达、超氧化物歧化酶水平均显著升高(P<0.05);④结果表明,脐血间充质干细胞移植可以有效促进脑梗死大鼠神经功能恢复,能够提高脑组织端粒酶反转录酶表达,移植时间越早效果越显著。

BACKGROUND:Umbilical cord blood-derived mesenchymal stem cells can penetrate the ependyma into the brain tissue via the systemic circulation,migrate into the injury area and differentiate into neurons.They are as substitute cells applied in the treatment of central nervous system diseases OBJECTIVE:To explore the effects of umbilical cord blood-derived mesenchymal stem cell transplantation on the functional recovery of nerve and expression of telomerase reverse transcriptase in the brain tissue of cerebral infarction rats.METHODS:One hundred and thirty rats were enrolled and were randomly divided into control group(n=30),model group(n=30),umbilical cord blood-derived mesenchymal stem cell 1 group(n=35)and umbilical cord blood-derived mesenchymal stem cell 2 group(n=35).The control group was not given any treatment.The rat models of cerebral infarction were made by internal carotid artery suture method in the other groups.At 1 and 4 days after successful modeling,2×106 umbilical cord blood-derived mesenchymal stem cells were transplanted into tail vein in the umbilical cord blood-derived mesenchymal stem cell 1 and 2 groups.The levels of reactive oxygen species and superoxide dismutase were detected at 24 hours after transplantation.The nerve function score was detected by Y-maze test at 7 and 14 days after transplantation.The neuronal apoptosis in the center of lesions was detected by TUNEL assay.The expression levels of Caspase-3,Bax,Bcl-2 and telomerase reverse transcriptase proteins around the infarct lesion were detected by western blot assay.The mRNA expression of telomerase reverse transcriptase around infarct lesions was detected by RT-PCR.RESULTS AND CONCLUSION:Compared with the control group,in the model group,the error number in the Y-maze test,nerve function scores,apoptotic index,expression levels of Caspase-3 and Bax,and level of reactive oxygen species were significantly increased(P<0.05),the expression of Bcl-2 and telomerase reverse transcriptase protein and mRNA,and level of superoxide dismutase were significantly decreased(P<0.05).Compared with the model group,in the umbilical cord blood-derived mesenchymal stem cell 1 and 2 groups,the error number in the Y-maze test,nerve function score,apoptotic index,expression of Caspase-3 and Bax,and level of reactive oxygen species were significantly decreased(P<0.05),while the expression of Bcl-2 and telomerase reverse transcriptase protein and mRNA and level of superoxide dismutase were significantly increased(P<0.05).Compared with the umbilical cord blood-derived mesenchymal stem cell 2 group,in the umbilical cord blood-derived mesenchymal stem cell 1 group,the error number in the Y-maze test,nerve function score,apoptotic index,expression of Caspase-3 and Bax,and level of reactive oxygen species were significantly decreased(P<0.05),while the expression of Bcl-2 and telomerase reverse transcriptase protein and mRNA and level of superoxide dismutase were significantly increased(P<0.05).These findings indicate that umbilical cord blood-derived mesenchymal stem cell transplantation can effectively promote the neurological recovery in rats with cerebral infarction,and up-regulate the expression of telomerase reverse transcriptase in rat brain tissue.Moreover,earlier cell transplantation indicates better effects.