非酒精性脂肪性肝炎大鼠肝脏内源性H_2S合成减少

目的探讨非酒精性脂肪性肝炎(nonalcoholic steatohepatitis,NASH)大鼠肝脏硫化氢(hydrogen sulfide,H2S)变化及与肝细胞线粒体损伤的可能关系。方法采用雄性SD大鼠26只,分为正常对照组(n=6),NASH模型组(n=10)及复方牛胎肝提取物治疗组(n=10),高脂饮食12周建立NASH大鼠模型。亚甲基蓝分光光度法测定肝组织H2S生成率,RT-PCR及免疫组织化学测定肝组织CSEmRNA及其表达。透射电子显微镜观察肝细胞超微结构、PCR法测定肝细胞线粒体DNA(mtDNA)片段ND1、ND6、CO1、CYB及ATP6。结果 NASH大鼠模型组肝细胞线粒体肿大、膜模糊或嵴消失,正常组大鼠mtDNA片段ND1、ND6、CO1、CYB及ATP6表达明显高于模型组和治疗组(P<0.05)。NASH模型组肝组织H2S生成率〔(1.26±0.08)nmol/min〕较正常组〔(2.11±0.17)nmol/min〕明显减少(P<0.05),且肝脏CSEmRNA水平及其表达减少,治疗组与模型组比较差异无统计学意义。结论 NASH大鼠肝脏H2S合成减少可能与肝细胞线粒体损伤有关,H2S在NASH发病机制中可能具有保护肝脏的作用。

The Beneficial Role of Endogenous H2S in Pathogenesis of Nonalcoholic Steatohepatitis Rats

Objective To investigate the production of H₂S and its protective role against mitochondrial dysfunction in rats with nonalcoholic steatohepatitis(NASH). Methods Twenty-six male Spague-Dawlay rats were randomly divided into 3 subgroups: normal group(n=6), NASH model(n=10), and compound fetal bovine liver extract treatment group(n=10). The NASH model was established by feeding rats with high fat diet for 12 weeks. The rate of production of H₂S was detected by methylene blue spectrophotometry and CSE mRNA was tested using RT-PCR. The mitochondrial morphology was assessed by transmission electron microscopy and the fragment of mtDNA, ND₁, ND₆, CO₁, CYB and ATP₆ were respectively tested by PCR. The hepatic steatosis and inflammation were evaluated using HE and Oil Red staining. Results In NASH rats, the hepatic tissue showed diffuse hepatic steatosis as lipid vacuolar degeneration with inflammatory cell infiltration, and the mitochondria showed swelling, becoming round, markedly abnormal morphology. The rate of liver production of H₂S in NASH rats was(1.26±0.08)nmol/min，which was significantly lower than that〔(2.11±0.17) nmol/min〕 in normal group(P<0.05). No significant difference in H₂S production between normal and treated group was observed. The decreased hepatic CSE mRNA and its protein were also observed. The level of mtDNA fragment, ND₁, ND₆, CO₁, CYB and ATP₆ in NASH rats were decreased. Conclusion The decreased hepatic H₂S production and CSE mRNA may be related to mitochondrial injury in NASH rats. Endogenous H₂S may play a beneficial role in pathogenesis of NASH.