扶正化瘀方对胰岛素样生长因子－1和磷脂酰肌醇3－激酶信号通路在自发逆转肝纤维化模型中变化的影响

Role of the IGF-1/PI3K pathway and the molecnlar mechanism of Fuzhenghuayu therapy in a spontaneous recovery rat model of liver fibrosis

目的探讨胰岛素样生长因子（IGF）－1和磷脂酰肌醇3－激酶（P13K）信号通路在自发逆转肝纤维化模型中的动态变化及扶正化瘀方对其影响的机制。方法实验大鼠分为对照组、自发逆转模型组（模型组）与扶正化瘀组。模型组和扶正化瘀组以四氯化碳（CCL-4）腹腔注射8周以建立肝纤维化模型，8周后模型组停用CCL,观察至14周，扶正化瘀组自ccl4造模同时以扶正化瘀方灌胃至8周。观察血清ALT、AST变化，用HE和Masson染色观察肝组织炎症和纤维化程度，免疫组织化学和RT-PCR法检测肝组织α－平滑肌肌动蛋白、IGF－1、P13K蛋白和mRNA表达。多组数据间比较采用单因素方差分析，Student-Newman-Keuls法进行组间比较，相关分析采用直线相关分析法。结果随CCl4造模时间延长，模型组大鼠肝组织炎症及纤维化逐渐加重，Ishak评分，羟脯氨酸含量、α-平滑肌肌动蛋白及IGF-1、P13K蛋白和mRNA表达逐渐升高，8周时达高峰。停用cch后随肝组织炎症和纤维化好转，Ishak评分、羟脯氨酸含量、α-平滑肌肌动蛋白表达及IGF-1、P13K蛋白和mRNA表达亦逐渐降低，到14周时各指标达到最低；扶正化瘀组第4、6、8周各时间点大鼠肝组织炎症和纤维化程度，Ishak评分，羟脯氨酸含量，α-平滑肌肌动蛋白，IGF-1和P13K蛋白及mRNA表达均较模型组相同时间点明显降低。结论IGF-1和P13K信号通路在肝纤维化发生和逆转中发挥重要作用，扶正化瘀方可通过阻断IGF-1、P13K信号通路及减少肝星状细胞活化等作用发挥抗肝纤维化功效。

Objective To determine the role of IGF-1/PI3K pathway and investigate the molecular mechanism of Fuzhenghuayu （FZHY） therapy in a spontaneous recovery rat model of liver fibrosis. Methods The liver fibrosis model was induced in male Wistar rats by administering 8 weeks of twice weekly CCL4 intraperitoneal injections without （untreated model） or with once daily FZHY （treated model）. Normal, untreated rats served as the control group. At weeks 4, 6 and 8 （fibrosis） and 10, 12 and 14 （spontaneous recovery） after modeling initiation, effects on protein （ct-SMA, IGF-1, PI3K） and mRNA （IGF-1, PI3K） expression levels were evaluated by immunohistochemistry and RT-PCR, respectively. Serum markers of liver function （alanine aminotransferase （ALT） and aspartate aminotransferase （AST））and liver cell damage （alkaline hydrolysis, HYP） were measured. Histology was performed to assess the degree of inflammation and fibrosis （Ishak scoring system）. Results In the untreated model group, progression of liver fibrosis （weeks 4, 6 and 8） was accompanied by gradual increases in inflammation, necrosis, serum ALT and AST, and hepatic expression of a-SMA protein and IGF-1 and PI3K protein and mRNA; however, during the spontaneous recovery period （weeks 10, 12 and 14） the IGF-1 and PI3K protein and mRNA levels rapidly decreased and the HYP level, Ishak score, and a-SMA hepatic expression also decreased. The FZHY-treated model group showed significantly lower fibrosis-related up-regulation of IGF-1 and PI3K protein and mRNA expression, HYP level, Ishak score, and a-SMA hepatic expression at each time point （vs. untreated model group）. Conclusion The IGF-1/PI3K pathway may contribute to progression of liver fibrosis. The mechanism by which FZHY prevents liver fibrosis in a rat model may involve blocking of the IGF/PI3K pathway and inhibiting HSC activation.