白藜芦醇对小鼠非酒精性脂肪性肝炎干预作用

Resveratrol induces autophagy and its interference effect on nonalcoholic steatohepatitis in a murine model

目的探讨自噬通路在白藜芦醇(RSV)减轻蛋氨酸-胆碱缺乏(MCD)饮食诱导的非酒精性脂肪性肝炎(NASH)中的作用及机制。方法雄性C57BL/6J小鼠40只,随机分为对照组、模型组、白藜芦醇低、高剂量组(100、250 mg/kg)(n=10);对照组和模型组小鼠分别喂饲基础饲料和MCD饲料,白藜芦醇组在喂饲MCD饲料同时给予RSV灌胃,4周后测定小鼠体重、肝重、血清中谷丙转氨酶(ALT)含量,分离小鼠肝脏,测定甘油三酯(TG)和丙二醛含量,苏木素-伊红染色观察肝组织形态学变化,油红O染色观察脂肪变性情况,Western blot检测自噬标志蛋白LC3及各通路蛋白的表达量。结果与对照组比较,模型组小鼠血清ALT和肝组织TG含量[分别为(144.17±0.32)U/L和(112.77±0.88)mg/g]明显升高(P<0.01),肝脏LC3Ⅱ和腺苷酸活化蛋白激酶(AMPK)表达水平[分别为(1.27±0.01)、(1.81±0.09)]升高(P<0.05);与模型组比较,高剂量白藜芦醇组小鼠血清ALT含量、肝组织TG含量[分别为(83.16±0.40)U/L、(40.75±0.19)mg/g]明显降低(P<0.01),LC3Ⅱ、AMPK蛋白表达水平[分别为(2.25±0.14)、(3.01±0.16)]明显升高(P<0.01);蛋白激酶B(Akt)和哺乳动物雷帕霉素靶蛋白(m TOR)表达水平无明显变化。结论白藜芦醇可以改善MCD饮食诱导的NASH,其机制可能与激活自噬AMPK途径有关。

Objective To investigate the effects of resveratrol-induced autophagy on nonalcoholic steatohepatitis in- duced with methionine- and choline-deficient（MCD） diet in C57BL/6J mice and its potential molecular mechanisms. Methods Forty male C57BL/6J mice were randomized into control group,MCD group,low-dose resveratrol group（ 100 mg/kg） and high-dose resveratrol group（250 mg/kg ） （10 mice in each group） ;the mice of control group and MCD group were fed with standard or MCD diet, respectively, and the intervention group were fed with MCD diet and given resveratrol by gavage at the same time. After 4 weeks, serum alanine aminotransferase （ALT） level was determined and triglycide（TG） and malondialdehyde（MDA） levels in liver tissue were also determined. The mice were executed to ob- tain the liver tissue for observing hepatic pathological and lipid changes. The expressions of proteins involved in the auto- phagic pathways were analyzed with Western blot. Results Compared with those of the control group, the serum ALT （ 144. 17 ± 0. 32 U/L） and liver TG （ 112. 77 ± 0. 88 mg/g ） levels in mice of MCD group increased （ P 〈 0. 01 ） ; the ex- pressions of microtubule-associated proteinl light chain 3 （ LC3Ⅱ ） （ 1.27 ± 0. 01 ） and adenosine monophosphate-activated protein kinase （AMPK） （ 1.81 ± 0.09 ） also increased （ P 〈 0.05 for all ）. Compared with those of the MCD group, the ALT（ 83.16 ± 0.40 U/L）and the TG（40. 75 ± 0. 19 mg/g）significantly decreased in the mice of high-dose resveratrol group （ P 〈 0. 01 for all）. Western blot revealed that the expression of LC Ⅱ （ 2. 25 ± 0. 14） and AMPK （3.01 ± 0. 16 ） in- creased significantly in the mice treated with high-dose resveratrol （P 〈 0.01 for all）, but protein kinase B （Akt） and mammalian target of rapamycin（mTOR） expression were not downregulated as expected. Conclusion Resveratrol inter- vention could attenuate nonalcoholic steatohepatitis in C57BL/6J mice with MCD diet and the effect may be related to the induction of autophagy through activating AMPK signaling pathway.