葛根素对大鼠肠缺血再灌注的肠黏膜iNOS基因表达的影响

Effect of puerarin on the expression of iNOS gene in the gut mucosa of intestinal ischemia-reperfusion rats

目的观察葛根素对肠缺血再灌注大鼠肠黏膜iNOS活性及基因表达的影响。方法♂SD大鼠分为假手术组、肠缺血再灌注2、8 h组、葛根素小、大剂量(70、140 mg.kg-1)+肠缺血再灌注2 h和8 h组、连续ip给药7 d。于第7天给药后30 min麻醉大鼠,复制肠缺血再灌注损伤模型。于再灌注后2、8 h观察大鼠小肠病理形态学的改变并检测血清中一氧化氮(NO)的含量及肠黏膜诱导型一氧化氮合酶(iNOS)的活性,用RT-PCR半定量测定iNOS mRNA的含量。结果大鼠应用葛根素和肠缺血再灌注2 h和8 h后,与模型对照组比较,可减轻肠黏膜的破坏;假手术组大鼠显示较低的黏膜iNOS活性、iNOS mRNA含量及血清NO水平,肠缺血再灌注后则表现出逐渐增加的趋势。至再灌注8 h,模型对照组的iNOS活性、NO水平较假手术组分别增加了64%、75%(P<0.05);而葛根素小、大剂量组则使黏膜的iNOS活性下降46%、50%(P<0.05),血清NO水平下降24%、43%,缺血再灌注2 h,肠黏膜iNOS mRNA表达已明显诱导上调,与再灌注8 h比较无明显差异,葛根素大剂量可使肠黏膜的iNOS mRNA含量显著降低。结论葛根素可降低肠缺血再灌注大鼠肠黏膜的iNOS活性和iNOS mRNA的表达,这可能是葛根素保护肠缺血再灌注损伤的作用机制之一。

OBJECTIVE To study the effect of puerarin on inducible nitric oxide synthase（iNOS） activity and iNOS gene in the gut mueosa of intestinal ischemia - reperfusion rats. METHODS A total of 42 rats were randomly divided into sham - operated group, intestinal ischemia reperfusion 2 h and 8 h group, high - dose puerarin treated group （ 140 mg·kg·d^-1） , low - dose puerarin treated group（70mg·kg·d^-1）. All treatment lasted for 7 days. The intestinal ischemia reperfusion was induced in rats by clamping superior mesenterie artery for 45 min followed by 2 or 8 h of reperfusion. Histological analysis was carried out in tissue samples. The serum nitric oxide（NO） concentration, inducible nitric oxide synthase（iNOS） activity and iNOS gene expression in the gut mucosa were measured. RESULTS Puerarin pretreatment could alleviate the mucosal histological disruption caused by intestinal ischemia reperfusion injury. It was shown that iNOS gene expression increased significantly at 2 h of reperfusion, while serum NO concentration, mucosal iNOS activity increased Significantly during 8 h of reperfusion, in contrast, mucosal iNOS gene expression decreased significantly in puerarin high - treated group（ P 〈 0. 01 ） CONCLUSION Puerarin can reduced inducible nitric oxide synthase （iNOS） activity and iNOS gene expression in the gut mucosa of intestinal ischemia - reperfusion rats, which might be one of mechanisms of its action.