瘦素在致大鼠肝纤维化形成中对AngII-ERK1/2信号通路的影响

Effect of AngⅡ-ERK1/2 signaling pathway in process of hepatic fibrosis induced by leptin

目的使用40%CCl4皮下注射诱导大鼠肝纤维化同时腹腔注射瘦素,通过组织切片和分子生物学及免疫技术检测肝组织的病理变化、瘦素、AngII及AT1R的表达。方法采用皮下注射CCl4造肝纤维化模型,对照组只注射生理盐水;肝纤维化模型组腹腔注射生理盐水;低剂量和高剂量瘦素组分别腹腔给予瘦素2ng/kg、20 ng/kg。每周2次,连续5周。采用HE、Masson组织染色及ELISA检测,RT-qPCR及免疫印迹检测AT1R等的表达。结果 HE染色显示瘦素组大多数肝细胞轻度肿胀,可观察到脂滴空泡,血管周围纤维组织增生,高剂量瘦素组最严重。Masson染色胶原纤维呈蓝色,正常组胶原纤维主要分布在血管壁,而模型组血管壁周围和细胞间质内均可见蓝色胶原纤维,瘦素组纤维化程度较模型组更严重。ELISA检测结果示肝纤维化模型组瘦素水平较对照组更高(P<0.05),不同浓度瘦素组比肝纤维化模型组瘦素表达更高(P<0.05),且高剂量与低剂量相比差异具有显著性(P<0.05)。RT-qPCR定量示AT1R随着瘦素浓度增加而上调;Western blot表明随着肝纤维化越严重,AT1R和pERK1/2表达越高。结论瘦素具促进肝纤维化的发生发展,而且在肝纤维化形成过程中对AngII-AT1R-ERK1/2信号通路也发挥了重要作用。

【Objective】To investigate the effect of leptin-induced hepatic fibrosison the AngII-ERK1/2 signaling pathway. 【Methods】40 rats were divided into four groups on average. Normal control group were injected with normal saline subcutaneously and injected with saline intraperitoneally. Model group were injected with 40% of carbon tetrachloride of castor oil subcutaneously, and injected with saline intraperitoneally. Low-dose leptin group were injected with 40% carbon tetrachloride of castor oil, while injectedwith leptin（2 ng/kg） intraperitoneally. High dose leptin group were injected with 40% carbon tetrachloride of castor oil subcutaneously, while injectedwith leptin（20 ng/kg） intraperitoneally, and all carbon tetrachloride was added by 3 mg/kg, twice a week, last for 5 weeks. Liver tissues were taken for HE, Masson staining and ELISA detection for leptin and AngII levels in liver tissue. AT1R was determined by RT-qPCR, and ERK1/2 levels were detected by Western blot in different groups. 【Results】HE staining showed that the majority of liver cells were a bit swollen, with vacuoles of lipid droplets,and with peri-vascular fibrosis, within the model and leptin groups. And high-dose leptin group had the most serious characteristics of hepatic fibrosis. Collagen fibers were stained with blue by Masson, normal collagen fibers were mainly distributed surrounding the vessel, and both surrounding the blood vessel and intercellular substance were visible in the model group and the leptin group, and the high-dose leptin groups were the most obvious. ELISA detection showed that leptin and AngII levels in the model group were all higher than the control group（P ＆lt;0.05）, and the leptin groups were higher than the model group（P ＆lt;0.05）, and high-dose leptin group were more significantly different compared with the low-dose group（P ＆lt;0.05）. According to the results of Quantitative RT-qPCR and Western blot, the highdose leptin group had the highest level of AT1R compared with normal control group, as well as the highest expression of pERK1/2. 【Conclusions】leptin can boost the hepatic fibrosis, and AngⅡ-AT1R-ERK1/2 pathway plays an important role in the occurrence and development of the hepatic fibrosis.