停通气缺氧预处理对脑出血后大鼠凋亡百分率和caspase-3和bcl-2表达的影响

Effects ofAsphyxial Hypoxic Preconditioning on Apoptosis Percents and the Expression of Caspase-3, Bcl-2 after lntracranial Hemorrhage in Rats

目的：观察停通气缺氧预处理对大鼠脑出血后细胞凋亡百分率以及caspase-3和bcl-2表达的影响。 方法：180只雄性SD大鼠．体重260—290g，随机分为假手术组（S组,60只）脑出血组（I组，60只）和缺氧预处理组（P组，60只）。每组从存活大鼠中取40只在脑出血（ICH）后6h、24h、48h和72h各时间点进行检测。所有大鼠水合氯醛腹腔麻醉后行气管播管并给予肌松药维库溴胺（2mg·kg^-1）．机械控制通气。P组进行停通气1分钟、复通气5分钟的缺氧预处理反复4次。机械通气1小时后拔出气管导管，然后对P组和I组的动物采用立体定向技术．将50μl自体不凝血注入尾状植中．S组注入同样剂量的生理盐水。从存活鼠中每个时间点取5只大鼠．流式细胞仪PI检测细胞凋亡百分率，另取5只大鼠连续切片进行caspese-3和bcl-2免疫组化染色。 结果：P组和I组凋亡百分率（％）在24h明显增加，于72h出现高峰．P组凋亡百分率在注血后48h和72h分别为11.62±3.64和15.80±3.30，显著低于I组17.76±3.49和21.06±2.81。有极显著差异（P〈0.01）。Caspase-3阳性细胞在24h明显增多．72h过高峰．脑出血后24h．48h和72h时P组caspese-3阳性细胞数均少于I组差异显著（P〈0.01）。相反．P组48h时bcl-2阳性细胞数（18.71±1.19）明显高于I组（14.87±2．17），P〈0.01。 结论：停通气缺氧预处理既增强了凋亡的调节基因bcl-2的表达，又减少了凋亡执行器caspase-3的激活．降低细胞凋亡百分率．具有脑保护作用。

Objective： To observe the effects of asphyxial hypoxic preconditioning on apoptosis percents and the expression of caspase-3, bcl-2 after intracranial hemorrhage（ICH） in rats. Methods： 180 male SD rats were randomly allocated into three groups： sham group （Group S, n=60）, ICH group （Group I, n=60） and preconditioning group （Group P, n=60） 40 live rats in every group were detected at 6 h, 24 h, 48 h and 72 h after ICH. The rats were anesthetized with 10% chloral hydrate 40 mg·kg^-1 celiac injection, paralyzed with vecuronium 2mg·kg^-1 and mechanically ventilated. The rats in P group were pretreated with four times of preconditioning, by being stopped ventilation for 1 rain and reventilated for 5 rain per circle. One hour later, endotraeheal Catheter was extubated. ECH model was made by injection of 50μ autos blood into the caudate nucleus in group P and I, 50psaline in Group S Apoptosis percents were detected by flow cytometer （FCM） and the expression of caspase-3, bcl-2 in cerebral tissues were detected by using immunohistochemistry techniques at 6 h, 24 h, 48 h and 72h after intracerebral hemorrhage. Results： Apoptosis percents raised obviously at 24 h and peaked at 72 h in Group I and Group P. In group P apoptosis percent was 11.62 ± 3.64 and 15.80 ± 3.30 at 48 h and 72 h, respectively, which was much lower than that in groupl （17.76 ± 3.49 and 21.06 ± 2 81 ） （P〈0 01 ）. Caspase-3 expression raised obviously at 24 h and peaked at 72 h. The number of caspose-3 positive cells was more in group I than that in group P at 24 h, 48 h and 72 h after ICH. Whereas the number of bcl-2 positve cells in group P （18.71 ± 1.19） was more than that in group I （1467 ± 2.17） at 48h （P〈0.01）. Conclusion; As phyxial hypoxic preconditioning enhances the expression of bcl-2, decreases the expression of caspase-3, reduces apoptssis percents, and demonstrates cerebral protective effect after ICH in rats.