HIBD新生大鼠活性Caspase-3表达的动态变化

Expression of Cleaved Caspase-3 in Neonatal Rats with Hypoxic-Ischemic Brain Damage

目的 了解缺血缺氧性脑损伤 (HIBD)后 2 4h内脑组织活性Caspase - 3表达的动态变化。 方法 7d龄SD大鼠随机分为正常对照组和HIBD组 ,HIBD组分别观察到缺血缺氧后 3h ,6h ,12h ,2 4h。以免疫组化及WesternBlot方法观察各组活性Caspase- 3的表达。结果 随时间推移缺血缺氧后 2 4h内活性Caspase - 3阳性染色由细胞质性转向细胞核性 ,活性Caspase- 3阳性染色细胞明显皱缩。HIBD组受损侧枕部皮质区活性Cas pase - 3阳性细胞数于缺血缺氧 3h增多 ,6h有所下降 ,12h再次增多 ,并于 2 4h达高峰 ,均高于正常对照组 (P <0 .0 5或 0 .0 1) ;海马回CA1区活性Caspase- 3阳性细胞数则随时间延长而增多 ,并于 2 4h达高峰 ,均高于正常对照组 (P <0 .0 1或 0 .0 5 )。WesternBlot方法亦示HI后 3h开始损伤侧脑组织中出现Caspase - 3表达 ,6h时表达减弱、12h再次增高。结论 以活性Caspase - 3作为HIBD导致脑细胞凋亡的指标 ,可观察到HIBD后 2 4h内凋亡二次增多的动态变化现象 ,为掌握抗凋亡制剂治疗HIE的时机提供了一定的依据。

Objective To study the change of cleaved Caspase-3 expression within 24 hs following hypoxia ischemia brain damage (HIBD) in neonatal rats. Methods Seven day old rats were randomly assigned into control group and HIBD group. The Caspase-3 expression was assayed by the immunohistochemical staining and Western Blot analysis at 3, 6, 12 and 24 hs after hypoxia ischemia (HI). Results The positive staining of Caspase-3 transferred from cytoplasm to the nuclei and the cells were apparently condensed and shrunk within 24 hs after HI. The number of the cleaved Caspase-3 positive cells in the damaged cortex increased at 3 h, decreased at 6 h, increased again at 12 h and peaked at 24 h after HI, whereas the number in the damaged hippocampal CA1 region increased with time and peaked 24 hs after HI. The number of the Caspase-3 positive cell both in the cortex and the hippocampal CA1 region of the HIBD group at 3 h, 6 h, 12 h and 24 h was greater than that of the control group (P< 0.05 or 0.01 ). Caspase-3 expression was also found in the damaged brain tissue 3 hs after HI by Western blotting analysis. The intensity of the expression, decreasing at 6 h but increased again 12 hs after HI. Conclusions The character of brain cell apoptosis within 24 hs following HIBD, increase of apoptotic cells twice, may be found with Caspase-3 as the marker for evaluating brain cell apoptosis in HIBD and it may be as reference for using anti apoptotic agents in treatment of HIE.