诱导性一氧化氮合酶在大鼠肝缺血再灌注损伤中的作用

目的 探讨诱导性一氧化氮合酶（iNOS）在大鼠部分肝缺血再灌注损伤中的作用.方法 选取雄性Sprague-Dawley大鼠30只,体重225～250 g,随机分成氨基胍（AG）组、脂多糖（LPS）组、对照组.每组均按相同方法建立70%的肝缺血再灌注损伤模型（缺血1 h,再灌注6 h）,取再灌注大鼠肝组织及血清样本.氨基胍（AG）组（n=10）：术前30 min尾静脉注射AG 100 mg/kg（质量浓度10 kg/L）;脂多糖（LPS）组（n=10）：术前30 min尾静脉注射LPS 10 mg/kg（质量浓度1 kg/L）;对照组（n=10）：术前30 min尾静脉注射生理盐水（10 μL/kg）.检测血清谷氨酸转氨酶（ALT）水平,实时荧光定量PCR测定肝组织iNOS mRNA的表达,Western blot测定肝组织iNOS蛋白的表达,考马斯法测定肝组织匀浆丙二醛（MDA）含量、超氧化物歧化酶（SOD）活性,HE染色光镜下组织学观察等.结果 AG组与对照组相比,肝组织中iNOS mRNA表达量明显下降（P〈0.05）,iNOS蛋白表达量明显下降（P〈0.05）;ALT和MDA明显下降（P〈0.05）;SOD明显升高（P〈0.05）;肝细胞水肿较轻,排列相对整齐.LPS组与对照组相比,肝组织中iNOS mRNA表达量明显升高（P〈0.05）,iNOS蛋白表达量明显升高（P〈0.01）;ALT和MDA明显升高（P〈0.05）;SOD则明显降低（P〈0.05）;肝细胞水肿,排列紊乱,并且出现水样变性.结论 iNOS 升高会加重缺血再灌注损伤,这一过程可能通过改变氧化还原状态实现.

Role of inducible nitric oxide synthase in liver ischemia-reperfusion injury in rats

Objective To study the role and mechanism of inducible nitric oxide synthase （iNOS） in liver ischemia-reperfusion injury in rats. Methods An ischemia-reperfusion （IR） process of 1 h isehemia and then 6 h reperfusion was performed on 30 male Sprague-Dawley rats. The rats then were randomly divided into 3 groups： IR （control） group, aminognanidine （AG） group, and lipopolysaceharide （LPS） group, 10 for each. The 3 groups were injected 10 p,L/kg of saline, 100 mg/kg of AG and 10 mg/kg of LPS through tail vein, respectively. The expression of the iNOS mRNA and protein, the level of alanine aminotransferase （ALT） in serum, malondialdehyde （MDA） and superoxide dismutase （SOD） in liver tissues were determined and histology was observed in 6 hours after reperfusion. Results Compared to the control group, the expression of the iNOS mRNA and protein was lower in the AG group but higher in the LPS group, both with statistically significant difference （ P 〈 0.05 ）. The level of ALT in serum samples and MDA in liver of the AG group were significantly higher than that of the control group （ P 〈 0.05 ） and the level of SOD was lower （ P 〈 0.05 ）, but the changes of these indices were opposite in the LPS group. Histology showed an edema in the control group. The edema was ameliorated in the AG group, while severed and even degenerated in the LPS group. Conclusion The elevation of iNOS contributes to the severe ischemia-reperfusion injury and the effect may be caused by influencing the oxidation and reduction environment.