血红素加氧酶-1在非酒精性脂肪性肝炎进展中的作用

目的 探讨血红素加氧酶-1(HO-1)在非洒精性脂肪性肝炎进展中的作用及其机制.方法 选用健康雄性C57BL/6J小鼠,采用胆碱-蛋氨酸缺乏饮食(MCD)4周建立小鼠非酒精性脂肪性肝炎模型,以胆碱-蛋氨酸充足饮食设立对照组,并以MCD加HO-1激动剂血晶素或抑制剂锌原卟啉进行干预实验.小鼠血清ALT和AST采用全自动生化仪酶法测定.HE染色观察肝脂肪变、炎症活动及纤维化程度;逆转录聚合酶链反应和Western blot检测HO-1、肿瘤坏死因子(TNF)α和白细胞介素(IL)-6 mRNA及其蛋白的表达.结果 MCD喂养小鼠血清ALT及AST明显异常,出现中～重度肝细胞脂肪变性,伴有点状和灶状肝细胞坏死、炎性细胞浸润、轻度汇管区纤维组织增生及窦周纤维化;HO-1、TNF α和IL-6 mRNA及其蛋白的表达较对照组显著增强,相对表达量分别为1.13±0.11、1.74±0.05,0.20±0.01、1.92±0.10,0.58±0.02、2.06±0.05对比0.43±0.02、0.75±0.05,0.08±0.00、0.59±0.02,0.22±0.01、0.91±0.02(P＜0.01);应用血晶素小鼠随肝脏HO-1 mRNA及其蛋白表达的上调及TNF α和IL-6 mRNA及其蛋白表达的下调(P＜0.01),肝脂肪变及炎症活动度均显著减轻;而应用锌原卟啉小鼠,肝脏HO-1 mRNA及蛋白表达明显受抑制,TNF α和IL-6 mRNA及蛋白表达则明显增强(P＜0.01),肝脂肪变及炎症亦随之显著加重.结论 抗氧化基因HO-1靶向性激活可阻止非酒精性脂肪性肝炎的发生及进展.

The role of heme oxygeanse-1 in non-alcoholic steatohepatitis

Objective To investigate the potential role of heme oxygeanse-1 on preventing nonalcoholic steatohepatitis (NASH) in mice. Methods Experimental models of NASH were established by feeding male C57BL/6J mice with choline-methionine deficient diet (MCD) for four weeks. Control animals were fed with choline-methionine supplemented diet. The treatment groups were fed with MCD diet combined with HO-1 inducer hemin or inhibitor zinc protoporphyrin Ⅸ (ZnPP-Ⅸ). Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were tested by enzymic method with automatic biochemistry analyzer. The degree of hepatic steatosis, inflammation and fibrosis were examined under HE staining.The hepatic mRNA and protein expressions of HO-1, TNF α and IL-6 were analyzed by RT-PCR and Western blot respectively. Results MCD fed mice showed increased serum ALT and AST levels and moderate to severe hepatic steatosis with inflammatory infiltration, hepatic spot or focal necrosis, light portal and sinus hepaticus fibrosis in the liver sections, which associated with enhanced expression of HO-1, TNF α and IL6 mRNA and protein (1.13 ± 0.11, 1.74 ± 0.05; 0.20 ± 0.01, 1.92 ± 0.10; 0.58 ± 0.02, 2.06 ± 0.05 vs 0.43±0.02, 0.75 ± 0.05; 0.08 ± 0.00, 0.59 ± 0.02; 0.22 ± 0.01, 0.91 ± 0.02). Administration of hemin significantly decreased serum ALT and AST levels and attenuated hepatic steatosis and necroinflammation which associated with up-regulation of antioxidative gene HO-1 and down-regulation of pro-inflammatory cytokines TNF α and IL-6 (P ＜ 0.01). A contrary effect on serum aminotransferase levels and liver histopathology was observed in mice injected with ZnPP-Ⅸ (P ＜ 0.01). The effect was associated with suppressed HO-1 expression and increased TNF α and IL-6 expression. Conclusions The data provided a biochemical,morphological and molecular biological evidence for the protective role of HO-1 in ameliorating hepatic steatosis, necroinflammation in experimental nutritional steatohepatitis.