人脐血MSCs移植修复大鼠脊髓损伤的效果及机制的初步探讨

Effects and mechanism of the transplantation of human umbilical cord blood msenchymal stem cells to treat spinal cord injury

目的探讨人脐血间充质干细胞(MSCs)移植修复大鼠脊髓损伤的作用及机制。方法分离纯化人脐血MSCs;制备大鼠脊髓半横断损伤模型,随机分为三组,分别在术后3 d经尾静脉注射生理盐水、培养液和BrdU标记的MSCs。移植后7、14、21、28 d,采用BBB评分法评估各组大鼠脊髓功能恢复情况;免疫荧光双标法检测MSCs在脊髓内的迁移、存活和分化,免疫组织化学法检测炎症因子高迁移率族蛋白B1(HMGB1)和核因子(NF-κB)在脊髓损伤部位的表达规律。结果移植后28 d,MSCs移植组大鼠肢体功能恢复明显,与生理盐水组和培养液组比较差别有统计学意义(P<0.05)。移植后7、14、21d,脊髓损伤区及周边均可见大量Brdu+细胞,其中BrdU+GFAP+细胞约占53.3%,BrdU+NSE+细胞约占22.15%。相同时间点MSCs移植组HMGB1和NF-κB的阳性表达率远低于生理盐水组和培养液组,差别有统计学意义(P<0.05)。结论人脐血MSCs移植后可替代损伤的神经细胞,并可减轻脊髓损伤后的炎症反应,从而促进大鼠脊髓功能的恢复。

Objective To explore the therapeutic effect and mechanism of mesenchymal stem cells（MSCs） derived from human umbilical cord blood on rat spinal cord injury.Methods MSCs were separated and purified from human umbilical cord blood.The spinal cord semi-transection was done on adult rats and then the animals were randomly divided into three groups which were treated with BrdU labeled MSCs,culture medium or saline respectively.Functional outcome was measured using the Basso-Beattie-Bresnehan（BBB） score method periodically up to 28 days post-surgery.MSCs survival and migration were observed by immunofluorescence double labeling techniques.The expression pattern of HMGB1 and NF-κB were detected by immunohistochemical techniques.Results BBB score showed that locomotor improvement in MSCs transplantation groups was much better than that of normal saline group and culture medium group at 28 days post-transplantation（P0.05）.BrdU-labeled MSCs could be detected in the lesion area at 7,14 and 21 days post-transplantation.53.3% of transplanted BrdU-positive cells were GFAP-positive,and 22.15% of them were NSE-positive.The positive rate of HMGB1 and NF-κB expression in MSCs transplantation group were lower than that in saline group and culture medium group,and there was a significant differences among three groups（P0.05）.Conclusions MSCs could promote functional recovery of the injuried spinal cord by replacing damaged nerve cells and alleviating inflammatory reaction.