非酒精性脂肪性肝炎发病机制的实验研究

Experimental study on the pathogenesis of nonalcoholic steatohepatitis

目的 通过建立大鼠非酒精性脂肪性肝炎 (NASH)动物模型 ,探讨NASH的发病机制。方法 通过持续 12周的高脂肪、高胆固醇饮食建立大鼠NASH模型 ,造模结束时检测模型组及正常组血清转氨酶、游离脂肪酸 (FFA) ;测定肝匀浆丙二醛 (MDA)、超氧化物歧化酶 (SOD)、FFA ;用免疫组化法标记肝组织细胞色素P45 0ⅡE1(CYPⅡE1)及溶菌酶 (LYZ)免疫阳性细胞———Kupffer细胞。 结果 造模大鼠存在血清和肝匀浆FFA升高 ,肝匀浆脂质过氧化终产物MDA增加 ,而抗氧化物质SOD减少 ,肝组织免疫组化示CYPⅡE1呈高表达 ,Kupffer细胞明显增多。相关分析表明 :随着FFA的增加 ,CYPⅡE1表达增高 ,脂质过氧化损伤亦增强 ,并且肝脏炎症、坏死加剧。结论 FFA在NASH的发病机制中起着重要作用 ,FFA的增加及其所引起的一系列CYPⅡE1高表达、Kupffer细胞激活以及脂质过氧化损伤 。

Objective To study the pathogenesis of nonalcoholic steatohepatitis(NASH) in rat model. Methods Male SD rats were fed with a high fat diet for 12 weeks. Non alcoholic ateatohepatitis serum lipid, aminotransferase values and free fatty acid (FFA) levels were tested, the malondialdehyde (MDA) and superoxide dismutase (SOD) activity of hepatic tissue were also detected. Hepatic cytochrome P450ⅡE 1 (CYPⅡE 1) were detected in liver section by immunohistochemistry using CYPⅡE 1 specific antibodies and also with an immunohistochemical procedure for detecting the number of Kupffer cells. Results FFA concentrations of the serum and hepatic tissue were markedly increased, which was accompanied by an increase of MDA in hepatic tissue, whereas SOD activity of hepatic tissue was decreased. CYPⅡE 1 immunostaining was markedly increased, especially in the perivenous region. The number of Kupffer cells in NASH was significantly increased compared with control livers. Correlation analysis revealed that the increases in the levels of FFA correlated positively with the hepatic CYPⅡE 1 expression, the lipid peroxidation, and the pathological scores in the liver of NASH rats. Conclusion The increased FFA, highly expressed CYPⅡE 1, activated kupffer cells and increased lipid oxidate were all contributed to NASH.