人端粒酶反转录酶基因修饰骨髓间充质干细胞移植治疗脑梗死

Human telomerase reverse transcriptase gene-modified bone marrow mesenchymal stem cell transplantation for cerebral infarction

背景:研究表明,人端粒酶反转录酶(human telomerase reverse transcriptase,hT ERT)具有加强细胞增殖能力、保持端粒长度恒定、延长体外培养细胞寿命等作用。目的:观察hT ERT基因转染骨髓间充质干细胞移植对脑梗死大鼠神经功能恢复的影响。方法:建立大鼠大脑中动脉阻塞模型,随机分为脑梗死组、骨髓间充质干细胞移植组和hT ERT转染骨髓间充质干细胞移植组,每组20只,分别于尾静脉注射1 m L PBS,1 m L第9代骨髓间充质干细胞悬液(细胞浓度2.5×107 L-1)和第9代h TERT基因转染骨髓间充质干细胞悬液(细胞浓度2.5×107 L-1)。于移植前及移植后对各组大鼠进行改良神经功能学评分,应用RT-PCR、Western Blot检测梗死脑组织中hT ERT基因及蛋白表达的变化,TUNEL法测定脑组织中细胞凋亡情况。结果与结论:hT ERT基因转染骨髓间充质干细胞的细胞生长周期明显延长,随着传代次数的增加,细胞生长良好,无明显形态改变;hT ERT转染骨髓间充质干细胞移植组的hT ERT基因及蛋白表达明显优于骨髓间充质干细移植组,差异有显著性意义(P<0.05);与脑梗死组及骨髓间充质干细胞移植组比较,hT ERT转染骨髓间充质干细胞移植组的神经功能缺损评分明显降低,脑组织中凋亡细胞数目明显减少(P<0.05)。结果显示hT ERT基因转染骨髓间充质干细胞能促进脑梗死大鼠神经功能恢复。

BACKGROUND： Studies have shown that human telomerase reverse transcriptase（h TERT） has the ability to enhance cell proliferation, maintain telomere length, prolonged cell life cultured in vitro. OBJECTIVE： To observe the effect of h TERT gene-modified bone marrow mesechymal stem cell transplantation on neural function recovery of rats with cerebral infarction. METHODS： Rat models of middle cerebral artery occlusion were established and randomized into model group, cell transplantation group and h TERT-modified cell transplantation group, with 20 rats in each group. Rats in the three groups were respectively injected via tail vein with 1 m L PBS, passage 9 bone marrow mesenchymal stem cell suspension（2.5×107/L） and h TERT-modified passage 9 bone marrow mesenchymal stem cell suspension（2.5×107/L）, respectively. Modified neurological severity scores were determined before and after transplantation;RT-PCR and western blot assay were used to measure h TERT expression at gene and protein levels; TUNEL method was adopted to detect cell apoptosis in the brain. RESULTS AND CONCLUSION： h TERT-modified bone marrow mesenchymal stem cells had prolonged cellcycle, and with the increase in passage number, the cells showed good growth with no changes in morphology. The expressions of h TERT m RNA and protein were superior in the h TERT-modified cell transplantation group than the cell transplantation group, and there was a significant difference（P 0.05）. Modified neurological severity scores and number of apoptotic cells were decreased significantly in the h TERT-modified cell transplantation group compared with the other two groups（P 0.05）. These findings indicate that h TERT-modified bone marrow mesenchymal stem cells can promote neural functional recovery of rats with cerebral infarction.