COX和CPT在非酒精性脂肪性肝病不同进展阶段中的变化

The expression change of COX and CPT in different stages of non-alcoholic fatty liver disease

目的通过NAFLD不同发展阶段的动物模型研究线粒体的细胞色素C氧化酶(COX)和肉毒碱棕榈酰转移酶(CPT))在NAFLD进展中的变化。方法建立单纯性脂肪肝(NAFL)和非酒精性脂肪性肝炎(NASH)的大鼠模型,通过大鼠肝脏病理切片HE染色和血清生化指标的检测验证模型的成立,使用RT-PCR和Western印迹检测大鼠肝脏的COX和CPT的mRNA和蛋白的表达量。同时在大鼠肝脏中提取线粒体,检测纯化的肝脏线粒体中两种酶的活性变化。结果 NAFL大鼠肝脏呈现轻度的脂肪变性和气球样变,NASH组大鼠肝脏则呈现弥漫的大泡性脂肪变和炎性浸润。与对照组相比,肝脏COX、CPT的基因和蛋白表达量在NAFL组和NASH组均降低(P<0.05)。在纯化线粒体中的检测提示,COX在NAFL和NASH组分别降低20%和35%,且NASH组显著低于NAFL组(P<0.05);CPT在NAFL和NASH组分别降低35%和50%,且NASH组显著低于NAFL组(P<0.05)。结论在NAFLD进程中,线粒体的能量转化和物质代谢功能都受到了不同程度的抑制,且随着疾病进展而加重。

Objective To investigate the regulation of cytochrome c oxidase （COX ） and carnitine palmitoyltransferase （CPT）in different stages of non-alcoholic fatty liver disease （NAFLD）in rat models.Methods The rat models of non-alcoholic fatty liver （NAFL）and non-alcoholic steatohepatitis （NASH）were established,and verified by histologic and biochemical analysis.The hepatic mRNA and protein levels of COX and CPT were measured by reverse transcription-polymerase chain reaction （RT-PCR）and western-blot,respectively.Mitochondria were separated from rat livers to analyze enzyme activity of COX and CPT.Results There were mild steatosis and inflammation in the liver of NAFL disease,while severe macrovesicular steatosis and lobular inflammation in the liver of NASH.The mRNA and protein levels of COX and CPT were decreased in both NAFL and NASH groups when compared with those in control group （P 〈0.05）.The enzyme activity of COX in mitochondria was decreased in both NAFL and NASH groups （0.2 and 0.35-fold decreased,respectively）,which showed significant difference （P 〈 0.05 ）;enzyme activity of CPT in mitochondria in NAFL group was decreased as 0.2 fold compared with 0.35 fold in NASH groups,which indicated that NASH group had a more severe decrease than NAFL group （P 〈 0.05 ）.Conclusion The energy metabolism and material metabolism in mitochondria are disturbed in different stages of NAFLD,which could be getting worse with progress of NAFLD.