下胸段硬膜外阻滞对失血性休克-复苏大鼠肠黏膜上皮细胞凋亡的影响

Effect of lower thoracic epidural block on intestinal epithelial cell apoptosis during hemorrhagic shock and resuscitation in rats

目的探讨下胸段硬膜外阻滞对失血性休克-复苏大鼠肠黏膜上皮细胞凋亡的影响。方法健康成年雄性SD大鼠64只,3月龄,体重280~320 g,硬膜外置管成功,随机分为四组,每组16只:假手术组(Sham组)、休克-复苏组(HSR组)、下胸段硬膜外注射生理盐水+休克-复苏组(NS组)、下胸段硬膜外阻滞+休克-复苏组(TEA组)。Sham组仅行硬膜外置管,不实施失血性休克,其余三组均采用改良Chaudry法制备失血性休克-复苏模型,放血前30 min TEA组硬膜外注射0.075%罗哌卡因100μl/kg,NS组注入等量生理盐水,HSR组不给予硬膜外注射。复苏后2 h采用化学反应法测定肠黏膜丙二醛(MDA)含量和超氧化物歧化酶(SOD)活性,采用TUNEL、免疫组化法分别测定肠黏膜细胞凋亡和Bcl-2、Bax蛋白含量。结果与Sham组比较,HSR组、NS组和TEA组肠黏膜Chiu评分、MDA含量、Bax蛋白含量、上皮细胞凋亡指数明显增高(P<0.05),SOD活性明显降低(P<0.05)。与HSR组和NS组比较,TEA组Chiu评分、MDA含量、Bax蛋白含量、上皮细胞凋亡指数明显降低(P<0.05),SOD活性和Bcl-2蛋白含量明显升高(P<0.05)。结论下胸段硬膜外阻滞可增强肠黏膜抗氧化、抗凋亡能力,从而抑制黏膜上皮氧化应激和细胞凋亡,保护肠黏膜屏障功能,以促进失血性休克-复苏后生存。

Objective To investigate the effect of lower thoracic epidural block on intestinal epithelial cell apoptosis during hemorrhagic shock and resuscitation in rats. Methods Sixty-four male SD rats placed with lower thoracic epidural catheter were randomly divided into four groups（ n = 16 each） ： group Sham（ sham operation）,group HSR（ hemorrhagic shock and resuscitation）,group NS（ hemorrhagic shock and resuscitation＋epidural saline 100 μl/kg）,and group TEA（ hemorrhagic shock and resuscitation ＋ epidural 0. 075% ropivacaine 100 μl/kg）.The hemorrhagic shock was made described by Chaudry. Rats were resuscitated by transfusing shed blood and normal saline 60 min after hemorrhagic shock. Malondialdehyde（ MDA） content,superoxide dismutase（ SOD） activity,and protein expression of Bax and Bcl-2 in intestinal epithelium were detected,and epithelial apoptosis index was calculated at 2 h after resuscitation.Results Compared with group Sham,intestinal epithelial MDA,Bax expression and epithelial apoptosis were significantly increased,while SOD activity were markedly decreased in groups HSR,NS and TEA（ P〈0. 05）. Compared with groups HSR and NS,intestinal epithelial MDA,Bax expression and epithelial apoptosis were significantly decreased,while SOD activity and Bcl-2 expression were markedly increased in group TEA（ P〈0. 05）. Conclusion Lower thoracic epidural block can enhance the antioxidant and antiapoptotic ability,and inhibit the oxidative stress and cell apoptosis of intestinal epithelium. Therefore,it can promote the survival rate after hemorrhagic shock and resuscitation through protecting intestinal barrier.