转化生长因子-β1对脊髓损伤后神经细胞凋亡的影响

摘要

Objective To investigate the effects of exogenous transforming growth factor β1 on the apoptosis of nerve cells and its functions following spinal cord injury in rats.Methods Ninety-six male Wistar rats were randomly divided into 4 groups:group A (control group),group B (spinal cord injured group),group C (spinal cord injuried +TGF-β1 treated group),group D (spinal cord injuried +anti-TGF-β1 treated group).The rat model of spinal cord injury was found by the Allen's method.In group C and D,drugs were injected into subarachnoid cavity continuously by minipump.The changes of spinal cord were observed by HE staining.Nerve cells apoptosis was detected by transferase-medi-ated dUTP nick end labeling (TNUEL) method and the expression of cell apoptosis factor Fas by immunohistochemistry staining.Functional recovery of hind limbs was measured by Basso-Beattie-Bresnahan locomotor open field behavioral rating test.Results The expression of TGF-β1and Fas increased following spinal cord injury.The amount of TGF-β1and Fas reached the peak 7days and 1day after injury.The apoptosis of neuron had increased and peaked 8 hours after injury.The apoptosis of neuroglia cells had increased and peaked 7 dayss after injury.The slight changes was found in spinal cord in group C.Both of the number of apoptosis of nerve cells and expression of the apoptosis factor (Fas) decreased significantly; compare with group B and D.The BBB score was higher in group C than that in group B and D.Conclusion TGF-β1 can improve the functional recovery of spinal cord by inhibiting the nerve cell apoptosis after the spinal cord injury.%目的 探讨转化生长因子(Transforming growth factor-β1,TGF-β1)对大鼠脊髓损伤后神经细胞凋亡及神经动能恢复的影响.方法 采用改良Allen's撞击法制作脊髓损伤大鼠模型,根据干预方式不同随机分为对照组、模型组、TGF-β1治疗组(渗透微泵持续蛛网膜下腔泵入1μg/h TGF-β1)、TGF-β1抗体组(渗透微泵持续蛛网膜下腔泵入1μg/h TGF-β1中和抗体),按设定的不同时间点随机处死各组的实验动物,取材.应用TUNEL法、RT-PCR、Westem blot和免疫组织化学染色分别检测不同组别在神经细胞凋亡,脊髓组织细胞中TGF-β1和Fas的mRNA及蛋白质表达差异.通过BBB运动功能评分法评估大鼠后肢运动功能恢复情况.结果 脊髓损伤后TGF-β1和Fas表达时间依赖性增加,Fas表达24h达高峰,TGF-β1表达7d达高峰.脊髓损伤后神经细胞凋亡增加,其中8h神经元凋亡明显,7d神经胶质细胞凋亡明显.局部应用TGF-β1,可显著下调损伤脊髓组织Fas表达,减少8h和7d时神经元凋亡及神经胶质细胞凋亡数量,BBB运动功能评分结果显示,TGF-β1治疗组大鼠后肢运动功能明显改善(P＜0.01).结论 脊髓损伤部位应用TGF-β1可抑制Fas mRNA及蛋白质的表达,减少脊髓损伤部位神经细胞的凋亡,有利于促进脊髓神经功能的恢复.