凝血酶对大鼠尾状核区神经细胞DNA损伤的动态研究

目的　研究脑出血血液凝固释放的凝血酶对神经细胞DNA的损伤 ,探讨脑出血神经细胞损伤的机制。方法　采用立体定位技术 ,将 15U凝血酶注入大鼠右侧尾状核 ,并用凝血酶的特异抑制剂水蛭素进行干预 ,于不同时相点测定TUNEL阳性细胞及caspase 3免疫反应性 (Immunoreactivity ,IR)细胞的表达。结果　凝血酶组TUNEL阳性细胞于造模后 12h出现 ,3d达到高峰 ,1周仍有较多表达 (P <0 0 1) ;caspase 3IR 6h开始表达 ,1d达高峰 ,1周仍有少量表达。水蛭素干预组TUNEL阳性细胞较凝血酶组明显减少 (12h ,1d ,3d ,1周 ,P <0 0 1) ;caspase 3IR较凝血酶组明显降低 (6h ,12h ,1d ,3d ,P <0 0 1;1周 ,P <0 0 5 )。结论　 15U的凝血酶可导致大鼠尾状核区神经细胞DNA损伤 ,损伤持续时间 1周以上 ;凝血酶释放很可能是脑出血神经细胞凋亡的机制之一。

Dynamic study on damage of nerve cell DNA in caudate nucleus induced by thrombin in rats

Objective To investigate the damage of nerve cell DNA induced by thrombin released during blood congulation in intracerebral hemorrhage (ICH) for mechanisms of apoptosis of nerve cells in ICH. Methods With the use of stereotaxic technique, 15U thrombin (TH) was injected into the right caudate nucleus of rat, and hirudin (HI), a specific inhibitor of thrombin, was used for intervention. Expression of TUNEL positive cells and caspase 3 IR cells was detected in the right caudate nucleus at different time points after operation. Results TUNEL positive cells appeared in the thrombin model 12 h after 15 U thrombin injection, reached a peak in 3rd day, and were present for more than 1 week. While the expression of caspase 3 began in 6 h, peaked in 1 d, and a few caspase 3 IR cells were still found in 1 week. However, the numbers of TUNEL positive cells in 12 h, 1 d, 3 d, 1 week after injection was decreased strongly in TH+HI group than in TH group ( P <0.01), so were the numbere of caspase 3 IR cells ( P <0.01 in 6 h, 12 h, 1 d, and 3 d; P <0.05 in 1 week). Conclusion The damage of nerve cell DNA in caudate nucleus can be induced by 15U thrombin, which lasts for more than 1 week, and thrombin's releasing may be one of the mechanisms for neural apoptosis after ICH.