在大鼠创伤性脑损伤模型中神经干细胞移植对突触素表达的影响

Effect of neural stem cells transplant on expression of synaptophysin in a rat model of traumatic brain injury

目的探讨神经干细胞(NSCs)移植对创伤性脑损伤(TBI)模型大鼠感觉运动功能的恢复作用及其对损伤脑组织中突触素(SYP)表达的影响。方法体外培养大鼠胚胎皮质NSCs;采用Feeney法制备TBI模型,于造模后72h,移植组采用PKH26荧光示踪剂标记的NSCs直接移植于脑损伤区,对照组以等量生理盐水代替NSCs;分别于移植后不同时间点,采用Gridwalk和Latency试验检测TBI大鼠的感觉运动功能;荧光显微镜下计数移植细胞的存活数量;采用免疫印迹和RT-PCR技术检测脑损伤区及周围组织中SYP的表达。结果 NSCs移植大鼠前、后肢功能分别在移植后第2w和4w恢复至手术前水平,而直到第8w,对照组大鼠后肢功能和通过平板移动时间与NSCs移植组和基线比较仍有显著性差异(P<0.05)。移植的NSCs随移植时间延长存活数量减少,移植后第4w和8w的存活数分别为6.3%±1.0%和4.1%±0.9%。在移植后的8w期间,移植组脑损伤区及周围组织中SYP的表达均明显高于对照组(P<0.05)。结论移植的NSCs在TBI脑内能够存活,并明显改善了TBI大鼠对侧肢体的感觉运动功能;NSCs移植促进了脑损伤区及周围组织中SYP的表达,这可能是NSCs移植促进功能恢复的机理之一。

Objective To evaluate the effect of neural stem cells（NSCs） transplant on sensorimotor function and synaptophysin（SYP） in injured-brain of a rat model of traumatic brain injury（TBI）.Methods Cortical NSCs derived from E14 rat embroes were cultured.A rat model of TBI was conducted according to previous report by Feeney.At 72 hours after TBI injury,the transplant group received delivery of the NSCs labeled by PKH26,while Gridwalkand Latency to move the control group received equivalent saline solution tests were used to evaluated the sensorimotor function of the animals.The number of surviving cells was quantified under fluorescent microscope.Western blot and RT-PCR were conducted to assess the expression of SYP in injured brain.Results NSCs transplant rats to returned to pre-surgery levels at 2 and 4 weeks in forelimb and hindlimb performance,respectively.However,Hindlimb performance and latency to move in saline control rats revealed significant difference compared to baseline and NSCs transplant rats at 8 weeks.Engrafted NSCs demonstrated a decrease in the number of survival cells during the 8-week period.The percentage of surviving cell is 6.3%±1.0% and 4.1%±0.9% of engrafted cells at 4 and 8 weeks post-transplantation,respectively.mRNA and protein expression of SYP were significantly higher in NSCs transplant rats compared to those in saline control rats during 8-week period post-transplantation（P0.05）.Conclusion NSCs transplanted directly into the injured brain are capable of surviving in a rat model of TBI.Engrafted NSCs increase expression of SYP in injured brain of TBI rats,which is suggested as one of the mechanisms underlying the improved functional recovery on sensorimotor behavior due to NSCs transplant following TBI.