BMSC对大鼠脊髓损伤神经凋亡的保护作用及相关机制研究

The protection mechanism of bone mesenchymal stem cells on the spinal cord injury via anti-neural apoptosis pathway

目的探索骨髓间充质干细胞(BMSC)对大鼠脊髓损伤(SCI)后神经凋亡的作用及其相关机制。方法体外获取大鼠BMSC进行增殖培养,利用流式细胞仪检测BMSC细胞表型,Allen法制作大鼠脊髓损伤模型,42只大鼠随机等分为3组,对照组,SCI组和BMSC+SCI组,分别于7 d、14 d和21 d对各组大鼠下肢运动功能评分;21 d后取出各组大鼠损伤脊髓进行组织切片染色,并利用Western blot法检测脊髓Bax/Bcl-2含量,ELISA法检测Caspase-3含量。结果 BMSC细胞表型CD90表达(98.92±0.62)%,CD34表达(0.47±0.16)%;BMSC在7 d、14 d和21 d可明显改善SCI大鼠下肢运动功能(P均<0.05);免疫组化结果显示,BMSC可显著抑制Bax和Caspase-3在损伤脊髓中的表达(P均<0.05);Western blot显示,BMSC明显抑制Bax,提高Bcl-2表达(P均<0.05);ELISA结果显示,BMSC可显著机制损伤脊髓中Caspase-3含量(P均<0.05)。结论 BMSC对大鼠脊髓损伤神经凋亡具有明显抑制作用,可能是通过抑制Bax、Caspase-3,提高Bcl-2蛋白表达实现的。

Objective To explore the effects of bone mesenchymal stem cells（ BMSC） on the spinal cord injury and the potential mechanisms. Methods BMSC were obtained via adherence method,and the cell phenotype was determined by flow cytometry. Spinal cord injury model was induced by using the modified weight-drop method at T8 level. 42 SD rats were randomly assigned to control group,SCI group and BMSC ＋SCI group. The rat hind limb was determined by the BBB（ Basso,Beattie,Bresnahan,BBB） at the 7 d,14 d and 21 d. At the day of 21,all groups of spinal cord were taken out and the HE staining and immunohistochemistry were valued. The protein expression of Bax and Bcl-2 were detected by western blot and the content of caspase-3 were valued by elisa. Results The CD90 expression of BMSC were（ 98. 92 ± 0. 62） %,while the CD34 were（ 0. 47 ± 0. 16） %. BMSC could effectively improve the BBB scores of the spinal cord injury（ P〈0.05）. Immunohistochemistry showed that BMSC could markedly suppress the content of Bax and caspase-3（ P〈0.05）. Western blot showed that BMSC could significantly suppress Bax and enhance Bcl-2 protein expression（ P〈0.05）. Elisa showed that BMSC could markedly down-regulate the content of caspase-3（ P〈0.05）. Conclusion The anti-neural apoptosis effects of BMSC on the spinal cord injury are via suppressing the Bax and caspase-3 protein expression and improving the Bcl-2 pathway.