干细胞移植对大脑中动脉闭塞模型鼠脑组织miR-34a及survivin表达的影响

目的观察骨髓间充质干细胞(BMSCs)移植对缺血再灌注损伤后大鼠脑组织miR-34a和survivin表达的影响,探讨BMSCs移植的抗凋亡和神经保护作用机制。方法将192只大鼠随机分为空白组、模型组、PBS液移植组和干细胞移植组;采用改良Longa线栓法制作大鼠大脑中动脉闭塞再灌注(MCAO)模型;通过尾静脉注射法行干细胞移植;改良大鼠神经功能缺损评分(m NSS)评估神经功能缺损;免疫组化检测survivin的表达;实时荧光定量PCR技术检测miR-34a的表达。结果干细胞移植组的神经功能缺损评分在12 h、1 d时与模型组比较无明显差异(P0.05);3 d、7 d时明显低于模型组(P0.05)。干细胞移植组的survivin阳性细胞率在各时间点均显著高于模型组(P0.05)。干细胞移植组的miR-34 a表达量在各时间点均显著低于模型组(P0.01)。结论大鼠脑缺血-再灌注损伤可致病灶区miR-34 a的表达上调;干细胞移植可明显改善脑缺血-再灌注大鼠的神经功能;移植干细胞可能通过下调病灶区miR-34a和上调survivin的表达发挥抗凋亡及神经保护作用。

Stem cell transplantation affects the protein expression of miR-34a and survivin in brain tissue in rats with middle cerebral artery occlusion

Objective To investigate the influence of bone marrow mesenchymal stem cell (BMSCs) transplantation on the protein expression of miR-34a and survivin in the brain tissue in rats with ischemia-reperfusion injury, as well as the anti-apoptotic and neuroprotective effects of BMSCs transplantation.Methods A total of 192 rats were randomly divided into blank group, model group, PBS transplantation group, and stem cell transplantation group. The modified Longa suture method was used to establish the rat model of middle cerebral artery occlusion (MCAO), and tail vein injection was performed for stem cell transplantation. The modified neurological severity score (mNSS) was used to evaluate neurological defects, immunohistochemistry was used to measure the protein expression of survivin, and quantitative real-time PCR was used to measure the protein expression of miR-34a.Results The mNSS scores at 12 hours and day 1 showed no significant differences between the stem cell transplantation group and the model group (P>0.05), while compared with the model group, the stem cell transplantation group had significantly lower mNSS scores on days 3 and 7 (P<0.05). Compared with the model group, the stem cell transplantation group had significantly higher rates of survivin-positive cells at all time points (P<0.05), and significantly lower protein expression of miR-34a at all time points (P<0.01).Conclusions The ischemia-reperfusion injury in brain upregulates the protein expression of miR-34a in lesions, and stem cell transplantation can significantly improve the neurological function in rats with ischemia-reperfusion. Stem cell transplantation exerts its anti-apoptotic and neuroprotective effects through downregulating miR-34a and upregulating survivin in lesions.