芝麻素对代谢综合征性脂肪肝大鼠肝组织iNOS和NT表达的影响

目的: 观察芝麻素对代谢综合征性脂肪肝大鼠肝组织诱导型一氧化氮合酶(iNOS)及硝基酪氨酸(NT)表达的影响。方法: 采用两肾一夹术伴高脂高糖饮食12周制备代谢综合征性脂肪肝大鼠模型。将成模大鼠随机分为模型组、芝麻素高、中、低剂量治疗组(120、60、30 mg·kg-1·d-1),另设假手术对照组;灌胃给药8周后,检测血清胆固醇(TC)、甘油三酯(TG)、游离脂肪酸(FFA)和肝组织超氧化物歧化酶(SOD)、丙二醛(MDA);应用Western blotting法检测大鼠肝组织中iNOS和NT的蛋白表达;HE染色观察肝组织病理变化。结果: 与模型组相比,高、中剂量治疗组芝麻素可降低大鼠血清TC、TG、FFA及MDA(P<0.05),提高SOD活性(P<0.05);抑制大鼠肝组织中iNOS和NT的蛋白表达(P<0.05),减轻肝组织脂肪变性。结论: 芝麻素对大鼠代谢综合征性脂肪肝病具有防治作用,其机制除了调脂作用外,可能还与下调iNOS、NT表达,减轻氧化应激损伤有关。

Effect of sesamin on expression of inducible nitric oxide synthase and nitrotyrosine in rat liver tissue with metabolic syndromic hepatic steatosis

AIM: To study the effect of sesamin on expression of inducible nitric oxide synthase(iNOS)and nitrotyrosine(NT)in rat liver tissue with metabolic syndromic hepatic steatosis. METHODS: The rat model of metabolic syndromic hepatic steatosis was induced by operation of two kidneys with one clip(2K1C)and high-fat. The rats taken from that successful model were randomly divided into model group and sesamin(120, 60, and 30 mg·kg-1·d-1)groups. In addition, the sham-operated group was set up. The rats in treated group were given sesamin intragastrically everyday for 8 weeks. The levels of blood lipids(TC, TG and FFA)in serum were detected. The activity of SOD and MDA level in the liver homogenate were determined. The expressions of iNOS and NT proteins were detected by Western blotting analysis. The histopathological changes were observed by HE staining in the liver tissues. RESULTS: Compared to model groups, sesamin(120, 60 mg·kg-1)significantly inhibited the elevation of serum TC, TG, FFA, and MDA in liver homogenate(P<0.05), and increased the activity of SOD(P<0.05). It also decreased the protein expression of iNOS and NT(P<0.05), and ameliorated the degree of hepatic steatosis. CONCLUSION: Sesamin prevents and cures the metabolic syndromic hepatic steatosis. The mechanism is probably mediated through decreasing the protein expression of iNOS and NT, and alleviating the oxidative stress in addition to regulating the lipid metabolism.