颞叶内侧癫癎海马CA1区CytC、caspase-9、caspase-3蛋白的表达研究

Expressions of cytochrome C,caspase-9 and caspase-3 in hippocampal CA1 field of medial temporal lobe epilepsy

目的探讨凋亡相关蛋白细胞色素C(CytC)、caspase-9、caspase-3在颞叶内侧癫癎(MTLE)病人致癎海马CA1区神经元内的表达及意义。方法选择30例典型MTLE病人为实验组,6例颞叶深部血管畸形病人为对照组。采用苏木精-伊红染色、原位末端标记(TUNEL)方法在光镜下观察MTLE病人致癎海马CA1区神经元凋亡的情况。采用免疫组化S-P法检测并比较MTLE海马CA1区与对照组海马组织神经元内凋亡相关蛋白CytC、caspase-9、caspase-3的表达。结合病史资料,分析caspase-3表达水平与癫癎病程和发作频率的相关性。结果MTLE组致癎海马CA1区光镜下可观察到神经元退变、噬神经元现象,TUNEL染色发现凋亡神经元18例,对照组则为阴性;CytC、caspase-9、caspase-3蛋白在MTLE组海马CA1区均有明显表达,对照组中则呈轻微表达,差异显著(P<0.01)。caspase-3蛋白表达水平与发作频率呈正相关,而与病程长短无关。结论MTLE致癎海马神经元中存在外源性凋亡途径,这可能是癫癎发展的重要因素之一。

Objective To explore the expressions and their significance of apoptosis correlated molecules, such as cytochrome C （CytC）, caspase-9 and caspase-3 in hippocampal CA1 field of patients with medial temporal lobe epilepsy （MTLE）. Methods Thirty patients with MTLE were included into the experimental group, while the control group was composed of 6 patients with deep vascular malformations in the temporal lobe. The apoptosis level in hippocampal CA1 field was determined by HE staining and TUNEL assay. The expressions of CytC, caspase-9 and caspase-3 in hippocampal CA1 field in the two groups were detected and compared by immunohistochemistry S-P method. The relationship between caspase-3 expression and both the course of disease and frequency of epileptic seizure was analyzed. Results Neuronal degeneration and phagocytosis were observed in all the specimens in the experimental group via HE staining, while neuronal apoptosis was observed in 18 specimens in TUNEL assay. High expressions of CytC, caspase-9, caspase-3 were detected in the experimental group, while low expression was seen in the control group, there being a significant difference between the two groups （P〈0.01）. The expression level of caspase-3 was positively related to the frequency of epileptic seizure in MTLE, but no direct correlation with the course of disease. Conclusion Extrinsic apoptosis exists in hippocampal neurons in MTLE and is one of the most important factors for epilepsy development.