大鼠脊髓半横断损伤后脊髓神经细胞凋亡与caspase-3的表达

Neuronal apoptosis and caspase-3 expression in the spinal cord after hemitransection injury in rats

为研究损伤脊髓神经细胞凋亡和相联系的caspase-3的表达,用原位末端标记法(TUNEL)检测了成年大鼠胸脊髓(T9)半横断损伤(hSCI)后脊髓神经细胞的凋亡变化,并用免疫组织化学染色方法观察了caspase-3的表达。结果显示:hSCI后6h损伤侧脊髓腹角即出现较多的TUNEL阳性神经细胞,并持续至5周。损伤脊髓的吻侧段于手术后4d达高峰,尾侧段脊髓于伤后1d达高峰。与假手术组相比,在所有观察的时间点TUNEL阳性神经细胞的数量在损伤侧均有明显增加。caspase-3免疫组化染色显示,与假手术组相比,伤后6h损伤侧脊髓腹角caspase-3表达也明显增加,并持续至5周。以上结果提示hSCI后,脊髓可出现神经细胞凋亡,且此凋亡的发生可能与caspase-3的表达有关。

To study neuronal apoptosis and the associated caspase-3 expression in the injured spinal cord, the thoracic cord （3＂9） underwent hemisected （hSCI） operation in adult rats. Neuronal apoptosis and caspase-3 expression were investigated by using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling （TUNEL） method and immunohistochemical technique. The results showed that the expression of TUNEL positive neurons, which were found in ventral horn of the spinal cord on the lesion side beginning from the 6 hour and remaining for 5 weeks, peaked at the 4 day rostral to the injury site but at the 1 day caudal to the injury site. Furthermore, the number of TUNEL positive neurons was significantly increased in the lesioned group than in the sham-operation group at all observed time points. Simultaneously, the number of immunoreactive neurons of caspase-3 increased significantly at the 6 hours and lasted for 5 weeks after hSCI on the lesioned side, compared with the sham-operation group. The present findings indicate the hemisection injury induces neuronal apeptosis in the spinal cord, which should be associated with caspase-3 expression.