两种给药途径致痫大鼠海马神经元超微结构损伤及caspase-3的表达特征

ULTRASTRUCTURAL DAMAGE AND CASPASE-3 EXPRESSION IN HIPPOCAMPAL NEURONS OF THE EPILEPTICUS RATS BY TWO ADMINISTER PATHWAY KINDLING

为了观察两种给药途径致痫大鼠海马神经元超微结构的损伤及caspase-3的表达特征,本研究分别采用海人酸腹膜腔注射(A组)和尾静脉注射(B组)诱发大鼠癫痫持续状态(SE)。分别于SE终止后3、6、24、48和72h取海马,电镜观察神经元超微结构的变化,免疫组化方法检测caspase-3的表达。结果显示:两组大鼠均在SE后3h出现线粒体损伤,细胞核的改变出现于SE后24h。A组致痫的潜伏期为97min±11min,神经元以凋亡为主;B组为48min±13min,神经元以坏死为主。SE后6～24h,两组大鼠海马内caspase-3的表达由胞浆向胞核逐渐移位,且均在SE后6h明显增高,24h达顶峰;A组高表达持续至72h,B组在48h显著降低。上述结果提示,线粒体的损伤出现于SE的早期,且可能是神经元损伤的关键环节;致痫方法不同,神经元的死亡形式也不同;而caspase-3的激活是神经元凋亡和坏死的共同通路。

To observe the ultrastructural damage and caspase-3 expression in hippocampal neurons of epileptic rats of different kindling by two administer pathway, both i. p. administration of kanic acid （ group A） and a tail vein injection of kanic acid （ group B） were employed to maximize variability in latency to onset of state epilepticus （SE）. The rats were killed and the hippocampus was taken out at 3,6, 24, 48 and 72 h after SE, respectively. The change of the neuronal ultrastructure was observed with electron microscope, and immunohistochemical staining was used to examine the expression of caspase-3 protein. The results were as follows ： both rats in two groups showed the mitechondrial damage 3 h after SE, and the change of nucleus was seen 24 h after SE. The latency of group A was 97 min ± 11 min, and most neurons showed apoptasis ; the latency of group B was 48 min ± 13 min, mast neurons showed necrosis. The expression of caspase-3 in both groups showed characteristic of transforming from cytoplasm to nucleus at 6 - 24 h after SE. At the same time, caspase-3 expression of both groups increased significantly at 6 h and reached the higher level 24 h after SE. Besides, in group A, caspase-3 remained higher level till 72 h, yet in group B, it decreased remarkably at 48 h. The above results suggest that mitechondrial damage appear in the early period after SE, which might be the key point of neuronal injury. The different method of kindling produce in different style of neuronal death, and activation of caspase-3 might be the common path of both apoptosis and necrosis.