磷酸化肌球蛋白轻链在大鼠非酒精性脂肪性肝纤维化中的表达

Expression of P-MLC in the rat non-alcoholic fatty liver fibrosis

目的探讨运用高脂饮食联合小剂量四氯化碳(CCl4)复制大鼠肝纤维化模型的特点,以及磷酸化肌球蛋白轻链[P-MLC(Thr18/Ser19)]在该纤维化模型中的作用。方法 70只SD大鼠随机分为正常对照组(N)、CCl4组(M1)和高脂饮食联合小剂量CCl4组(M2)。N组皮下注射花生油3 ml/kg,2次/周;M1组采用400 ml/L CCl4花生油混合液,3 ml/kg,2次/周皮下注射;M2组采用高脂饮食联合小剂量CCl4造模,其CCl4用量2 ml/kg,浓度和频次同M1组。造模后8周末、10周末分批处死,检测肝功能、血脂、光镜观察大鼠肝脏脂肪变性及肝纤维化程度。免疫组化法检测肝脏P-MLC的表达。结果与N组比较,8周和10周末,M1组血浆球蛋白(GLO)、谷丙转氨酶(ALT)、谷草转氨酶(AST)水平,P-MLC的表达及肝脂肪变性,纤维化程度均升高,但白球比(A/G)下降。与M1组比较,8周末,M2组ALT、AST下降,但脂肪变性增强;10周末,M2组白蛋白(ALB)、A/G下降,而ALT、AST上升明显;8周和10周末M2组P-MLC的表达及肝纤维化程度均强于M1组,差异均有统计学意义(P<0.05)。结论高脂饮食联合小剂量CCl4皮下注射复制大鼠肝纤维化模型,具有造模时间短,成功率高的优点。P-MLC的表达随着肝纤维化的进展而增加,P-MLC在非酒精性脂肪性肝纤维化中起着一定的作用。

Objective To investigate the characteristic of liver fibrosis in rat model by a compound method of injecting CCl4 subcutaneously in smaller dose and feeding high fat diet（HFD） daily at the same time,and explore the expression and significance of P-MLC in this model.Methods 70 SD rats were randomly divided into the normal control group（N）,CCl4 group（M1）,HFD＋small dose CCl4 group（M2）,treated with olive oil（3 ml/kg of body weight）,CCl4（3 ml/kg of body weight）,HFD＋CCl4（2 ml/kg of body weight） respectively.Rats in treatment with CCl4 were injected subcutaneously in a ratio of 2 ∶ 3 with olive oil twice a week.The rats were killed on the 56 th day and 70 th day.Histological analysis was carried out to assess the injury of the liver.Liver function,TG,TC and expression of P-MLC in liver were measured.Results Compared with N,serum GLO,ALT,AST levels,expression of P-MLC in liver and grade of hepatic steatosis and fibrosis were significantly higher,but A/G level was lower in group M1 both on the 56th day and 70 th day.Compared with M1,serum ALT,AST levels were lower,but grade of hepatic steatosis was significantly higher in group M2 on the 56 th day,but serum ALB,A/G levels decreased remarkably and ALT,AST levels were much higher in group M2 on the 70 th day.The degree of fibrosis and expression of P-MLC in group M2 were significantly higher than those in group M1 both on the 56 th day and 70 th day.Conclusion Injecting CCl4 subcutaneously in smaller dose and feeding HFO daily can make satisfied model of rat liver fibrosis,and can shorten the experimental time.The increased expression of P-MLC in liver may play an important role in NASH progression.