早期应用z-VAD-fmk对新生鼠HIBD的保护作用及其机制研究

Study on protective effect and its mechanism of pretreatment of Caspase-3 gene inhibiter on hypoxic-ischemic brain damage in the neonatal rats

目的观察半胱氨酸蛋白酶(Caspase)抑制剂z-VAD-fmk对于缺血缺氧性脑损伤(hypoxic-ischemic brain damage,HIBD)大鼠脑组织的保护作用,并探讨其机制。方法 7d龄Wistar大鼠60只,随机分为对照组、HIBD组和阻断组,各20只。HIBD组及阻断组制作HIBD模型,对照组大鼠分离但不结扎左侧颈总动脉,术后亦不进行缺氧处理。阻断组在建模后给予z-VAD-fmk,连续7d。第8天处死全部动物。分别采用TUNEL法和RT-PCR法检测三组动物脑组织中神经细胞凋亡指数(apoptosis index,AI)和Caspase-3mRNA。结果对照组、HIBD组、阻断组AI值分别为0.15±0.02、21.36±2.45、10.42±1.62,三组相比差异有统计学意义(P均<0.05)。三组脑组织中Caspase-3mRNA的相对表达量分别为0.016±0.003、0.561±0.067、0.216±0.036,三组相比差异有统计学意义(P均<0.05)。AI值随Caspase-3mRNA的升高而升高,随其降低而降低,二者之间具有正相关关系(r=0.628,P<0.05)。结论 z-VAD-fmk对HIBD大鼠脑组织有一定的保护作用,其机制可能是降低脑组织中Caspase-3mRNA的表达,减轻神经细胞凋亡。

Objective To study the effect of hypoxia ischemia brain damage （HIBD） of neonatal rats with cerebral cor- tex apoptosis by gene inhibiter so as to explore the possible mechanism. Methods Model of HIBD was built in neonatal rats,60 Wistar rats were randomly divided in： control group; HIBD group ; obstruct group（HIBD＋z VAD-fmk）. Adopting HE dyeing,three animal apoptosis index （AI） in brain and Caspase-3mRNA were detected by TUNEL and RT-PCR. Results Express of Caspase-3mRNA nanomolar in control group was significant heighten in HIBD group（P〈0.01）. There was significantly lower express between obstruct group and HIBD group （P 〈 0. 05）. AI value changed with Caspase- 3mRNA. They had significance positive correlation （r = 0. 628, P〈 0. 05）. Conclusion Express heigten of Caspase- 3mRNA leads to histiocytic apoptosis in HIBD group, and lower express of Caspase-3mRNA by z-VAD-fmk, could protect brain of neonatal rats.