大鼠脊髓半横断损伤后凋亡相关基因的表达变化

目的探讨脊髓半横断损伤后凋亡相关基因Bc l-2、Bax、Fas在蛋白水平的表达变化规律及神经细胞凋亡的分子生物学机制。方法在成年SD大鼠脊髓T9~T10间半横断,取损伤位点尾侧段T10节段制作冰冻切片,运用Bc l-2、Bax、Fas兔抗血清以免疫组化亲合素-生物素-过氧化物酶复合物法(ABC)法染色。观察并计数腹角Bc l-2、Bax、Fas的阳性神经元数。结果Bc l-2、Bax、Fas主要分布于正常大鼠脊髓腹角神经元细胞浆,损伤后腹角Bc l-2、Bax、Fas阳性神经元数在3 d组(n=6)、7 d组(n=6)、21 d组(n=6)均较假手术组(n=6)明显增加(P<0.01),Bax、Fas阳性神经元数在术后3d时达高峰,随伤后时间的延长进行性减少(P<0.05)。Bc l-2阳性神经元数在术后7 d时达高峰,3 d组与21 d组比较没有显著差异。结论脊髓半横断损伤(hSC I)后,由Fas抗原参与的死亡受体途径及Bc l-2、Bax参与的线粒体途径均参与了hSC I后细胞的凋亡过程。

The changes in the expression of apoptotic correlative genes(Bax, Bcl-2, Fas) in neurons following hemisection spinal cord injury

Objective To explore the changes in the expression of apoptotic relative genes(Bax,Bcl-2,Fas) in the spinal cord ventral horn neurons in early stage after hemisection spinal cord injury(hSCI).Methods(Hemisection) spinal cord injury was performed between T_(9) and T_(10) in adult Sprague-Dawley(SD) rats.The rats were sacrificed 3 d,7 d and 21 d after operation respectively,and the T_(10) spinal segments were removed out.(Immunohistochemical) ABC staining was used and the positive neurons numbers were counted.Results Bax,Bcl-2,Fas positive staining were mainly distributed in cytoplasm of neurons located in the spinal ventral horn in the normal group.The number of Bax,Bcl-2,Fas positive neurons apparently increased in the 3 d(n=6),7 d(n=6) and 21 d(n=6) groups compared to that of the sham-operational group(P<0.01).The Bax,Fas positive neurons reached a peak at 3 d after injury,and decreased progressively with time following hSCI(P<0.05).Bcl-2 positive neurons reached a peak at 7 d after injury(P<0.01) with no difference in the number of Bcl-2 positive neurons between 3 d and 21 d groups.There exists high expression of apoptotic relative genes Bax,Bcl-2,and Fas after hSCI.Conclusion A delayed progressive destructive process causes even more severe spinal cord damage in a way of apoptosis.Bax,Bcl-2,and Fas protein are possible critical factors in this process.