静脉注射人脐血间充质干细胞对脑损伤神经生长因子的影响

目的 观察TBI后静脉注射人脐血间充质干细胞(CB-MSCs)对NGF、BDNF表达的影响,探讨其脑保护的作用机制.方法 清洁级健康雄性SD大鼠90只采用完全随机数字表法分为假手术组、损伤组和治疗组,每组30只.损伤组和治疗组采用改进的Feeney自由落体法制作大鼠TBI模型,假手术组只开骨窗,不撞击硬脑膜.治疗组尾静脉注入3×106个Brdu标记的CB-MSCs,损伤组及假手术组注入等体积的PBS液.在移植后3、7、14、21、28 d,采用HE染色、免疫组化染色、原位杂交法对TBI大鼠脑组织形态学变化、Brdu标记情况、NGF和BDNF表达情况进行检测.结果 假手术组仅有极少量的NGF、BDNF阳性表达细胞.损伤组表达明显增加,以损伤周边区最为明显,注射后14d达到高峰(NGFA值为8.35±1.07,BDNFA值为9.01±1.74),之后逐渐下降,但仍高于假手术组,差异有统计学意义(P＜0.05).治疗组表达趋势与损伤组相同,14d达高峰后,21 d、28 d阳性表达明显下降;各时间点均高于损伤组与假手术组,差异有统计学意义(P＜0.05).结论 在TBI中,静脉注射CB-MSCs可以增加损伤局部NGF、BDNF的分泌,改善局部微环境,促进神经元的修复.

Intravenous injection of human umbilical cord blood mesenchymal stem cells affecting the level of nerve growth factors in rats with traumatic brain injury

Objective To investigate the effect of transplantation of human umbilical cord blood mesenchymal stem cells (CB-MSCs) on the levels of NGF and BDNF in rats with traumatic brain injury (TBI) and explore its possible mechanism of cerebral protection. Methods Ninety healthy male SD rats were equally randomized into sham-operated group, injury control group and treatment group.TBI models in the injury control group and treatment group were induced by the improved device of Feeney weight-dropping; the rats in the treatment group were injected Brdu-labeled 3×106 CB-MSCs solved in 1ml PBS by rat-tail vein, while the rats in the sham-operated group and the injury control group were injected the equal volume of PBS solution. No immunosuppressive agents were used in all the rats.HE staining, immunohistochemistry, in-situ hybridization were employed, respectively, to detect the morphological changes, Brdu positive cells, expressions of BDNF and NGF on the 3rd, 7th, 14th, 21st and 28th d of injection. Results Only a very small number of nerve cells were BDNF and/or NGF positive in the sham-operated group. Substantial BDNF and/or NGF positive cells in the injury control group were noted in the surrounding brain damaged area following traumatic brain injury, which peaked at their levels on about 14 d of injection (the A value of NGF=8.35±1.07, that of BDNF=9.01±1.74), following by a gradual decline; however, significant difference was still noted as compared with that in the sham-operated group (P＜0.05). BDNF and/or NGF-positive cells significantly increased in the treatment group, especially in the surrounding brain injured areas; their levels peaked on the 14th d of injection,following by a gradual decline on the 21st and 28th d, but they were still higher than those in the injury control group and sham-operated group at each time points (P＜0.05). Conclusion Transplantation of CB-MSCs can increase the secretion of BDNF and NGF in rats with TBI, improve the local micro-damage environment and promote the repair of neurons.