大麻二酚对大鼠非酒精性脂肪肝的治疗作用及机制

摘要

目的 观察大麻二酚(CBD)对蛋氨酸/胆碱缺乏饲料(MCD)诱导的大鼠非酒精性脂肪肝(NASH)的治疗作用并探讨其分子机制.方法 63只成年雄性SD大鼠随机分为对照组(给予正常饲料)、MCD组(给予MCD喂养)和MCD+CBD组[给予MCD,同时给予2mg/(kg·d)CBD腹腔注射].10周后,组织染色法观察大鼠肝脏病理变化及纤维化情况,采用全自动生物化学分析仪检测血清丙氨酸转氨酶(AST)、天冬氨酸转氨酶(ALT)水平,生化试剂盒检测肝脏中胆固醇和甘油三酯水平,Western blotting法观察肝细胞自噬活性的变化.结果 MCD喂养的大鼠给予CBD后,肝脏的病理改变明显减轻(4.7±1.1 vs.2.2±0.5,P<0.05),血清ALT(214.5±54.1U/L vs.92.1±36.0U/L,P<0.05)和AST(175.9±55.2U/L vs.70.8±24.9U/L,P<0.05)水平明显下降,肝脏/体重比(%)降低(4.2±0.6 vs.3.1±0.6,P<0.05),肝脏中胆固醇(182.4±42.7mmol/mg protein vs.101.0±33.8mmol/mg protein,P<0.05)和甘油三酯(71.4±12.5mmol/mg protein vs.38.7±11.1mmol/mg protein,P<0.05)含量减少;肝脏的纤维化程度降低(1.4%±0.4%vs.0.8%±0.3%,P<0.05),Ⅰ型α1胶原(Col1A1)mRNA水平明显下降(2.9±0.4 vs.1.6±0.3,P<0.05).CBD治疗后,MCD大鼠肝脏中Ⅱ型微管相关蛋白1轻链3(LC3-Ⅱ)/LC3-Ⅰ比值增加(37.1±10.8 vs.71.2±17.1,P<0.05),可溶性死骨片1(p62)蛋白水平降低(202.4±40.9 vs.125.8±32.7,P<0.05).结论 CBD减轻了MCD诱导的大鼠NASH症状,CBD对肝细胞自噬流的促进可能是其肝脏保护作用的机制之一.%Objective To observe whether treatment with cannabidiol (CBD) affect nonalcoholic steatohepatitis (NASH) induced by methionine choline-deficient diet (MCD) in rats and investigate the underlying molecular mechanism. Methods Sixty-three adult male SD rats were randomly divided in to three groups as follows: Control group (rats fed with normal diet), MCD group (rats fed with MCD and MCD+CBD group [rats fed with MCD and treated with cannabidiol, 2mg/(kg.d), i.p.]. Ten weeks later, steatohepatitis and fibrosis were evaluated by hematoxylin-eosin and Masson staining, respectively. Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were measured by using an automatic biochemical analyzer and hepatic levels of cholesterol and triacylglycerol were determined with kits. Autophagic flux in livers was evaluated by Western blotting. Results Treatment with cannabidiol reduced ratio of liver/body weightratio (4.2%±0.6% versus 3.1%±0.6%, P<0.05), histological scores (4.7±1.1 versus 2.2±0.5, P<0.05) and fibrosis (1.4%±0.4% versus 0.8%±0.3%, P<0.05) in rat livers, lowered levels of ALT (214.5±54.1U/L versus 92.1±36.0U/L, P<0.05) and AST (175.9±55.2U/L versus 70.8±24.9U/L, P<0.05) in serum, attenuated hepatic fat accumulation (cholesterol, 182.4±42.7mmol/mg protein versus 101.0±33.8mmol/mg protein, P<0.05; triglyceride, 71.4±12.5mmol/mg protein versus 38.7±11.1mmol/mg protein, P<0.05), and down-regulated mRNA expression of Col1A1 (2.9±0.4 versus 1.6±0.3, P<0.05) in livers of rats fed with MCD. Furthermore, cannabidiol led to the LC3 turnover (LC3-Ⅱ/LC3-I, 37.1±10.8 versus 71.2±17.1, P<0.05) and p62 decrease (202.4±40.9 versus 125.8±32.7, P<0.05) in the livers of MCD-fed rats. Conclusion Treatment with cannabidiol could relieve MCD-induced NASH in rats, at least in part, by autophagic flux promotion.