亚低温缺血预处理对大鼠缺血再灌注肠保护作用的研究

Protective effect of ischemic-preconditioning under the mild hypothermia against small intestine ischemia-reperfusion injury in rats

目的探讨亚低温缺血预处理对缺血再灌注肠的作用及机制。方法32只大鼠随机分为4组(每组8只),比较假手术对照组(sham)、缺血再灌注组(I/R)、缺血预处理组(IP)、亚低温预处理组(MHIP)小肠组织湿干重比、Ca2+-Mg2+-ATPase含量及血清乳酸脱氢酶(LDH)、超氧化物歧化酶(SOD)、丙二醛(MDA)水平、总抗氧化(TAX)能力的变化,并观察各组肠组织超微机构及Bcl-2、Bax蛋白表达。结果缺血再灌注后I/R组小肠湿干重比值、LDH、MDA含量、Bcl-2和Bax蛋白表达吸光度(A)值明显高于sham组(P<001);Ca2+-Mg2+-ATPase、SOD活性及TAX能力明显低于sham组(P<001)。IP组小肠湿干重比值、LDH、MDA含量、Bax蛋白表达吸光度值明显低于I/R组(P<001);Ca2+-Mg2+-ATPase、SOD活性及TAX能力、Bcl-2蛋白表达吸光度(A)值明显高于I/R组(P<001)。结论亚低温缺血预处理通过增加肠组织自身抗氧化能力、抑制脂质过氧化、上调bcl-2基因的蛋白表达与下调bax基因的蛋白表达以抑制肠组织细胞凋亡的发生等机制对抗肠缺血再灌注损伤。

AIM: To investigate the protective effect of ischemic-preconditioning under the mild hypothermia against small intestine ischemia-reperfusion injury in rats and its mechanism. METHODS: Thirty-two rats were randomized into 4 groups (8 rats in each group): sham operated group (Sham), ischemia-reperfusion (I/R) group, ischemic-preconditioning (IP) group, mild hypothermia ischemic-preconditioning (MHIP) group. The wet/dry ratio, Ca 2+ -Mg 2+ -ATPase activity in intestine tissue, the malondialdehyde (MDA) content, activities of lactate dehydrogenase (LDH), superoxide dismutase (SOD) and total antioxdase (TAX) in blood were determined. Ultrastructure, Bcl-2 and Bax expression in intestinal mucosa tissue were also observed. RESULTS: After I/R, the intestinal tissue wet/dry ratio, the content of MDA, LDH activity, the optic density of Bcl-2 and Bax proteins were significantly higher in I/R group than those in sham group (P<0.01). The activities of Ca 2+ -Mg 2+ -ATPase, SOD, TAX were significantly lower in I/R group than those in sham group (P<0.01). The intestinal tissue wet/dry ratio, the content of MDA, LDH activity and the optic density of Bax protein were significantly lower in IP group than those in I/R group (P<0.01), and also lower in MHIP group than in IP group (P<0.05). The activities of Ca 2+ -Mg 2+ -ATPase, SOD, TAX and the optic density of Bcl-2 protein were significantly higher in IP group than in I/R group (P<0.01). CONCLUSION: MHIP can protect intestine against I/R injury in rats, which may be related to enhancing oxidation-resistance of intestine, inhibiting lipid peroxidation, upregulating the expression of Bcl-2 protein and downregulating the expression of Bax protein. [