基于IFN-γ/STAT1/Smad7通路探讨疏肝健脾活血方抗肝纤维化作用机制

Discussion on the mechanism of Shugan Jianpi Huoxue Formula anti-liver fibrosis based on IFN-γ/STAT1/Smad7 pathway

目的:探讨疏肝健脾活血方防治肝纤维化的可能作用机制。方法:36只C57BL/6雄性小鼠随机分为正常组、模型组、中药组,每组12只;除正常组外,其余组小鼠利用20%四氯化碳(CCl4)诱导肝纤维化,中药组按33.3 kg/mL疏肝健脾活血方药灌胃干预,连续4周。采用HE染色、Masson染色、天狼猩红染色观察各组小鼠肝组织病理变化;免疫组化检测肝组织平滑肌α-肌动蛋白(α-SMA)分布情况;检测各组小鼠血清谷丙转氨酶(ALT)、谷草转氨酶(AST)水平变化;采用Western Blot法检测肝组织中Ⅰ型胶原(CollagenⅠ)、α-SMA、信号转导与转录活化因子1(STAT1)、磷酸化信号转导与转录活化因子1(p-STAT1)、Smad7蛋白表达水平;采用RT-PCR法检测各组小鼠肝组织中CollagenⅠ、α-SMA、Smad7、γ-干扰素(IFN-γ)mRNA水平变化。结果:与模型组比较,中药组肝组织中炎症细胞浸润减少,肝细胞点状坏死减少,肝细胞排列相对整齐,汇管区及中央静脉区纤维增生减少,部分纤维间隔消失,胶原沉积明显减少;血清中ALT与AST水平显著下降(P<0.01,P<0.05);肝组织中CollagenⅠ与α-SMA蛋白水平显著下降(P<0.05),Smad7与p-STAT1/STAT1蛋白水平显著上升(P<0.05);肝组织中CollagenⅠ与α-SMA mRNA水平显著下降(P<0.01),Smad7与IFN-γmRNA水平显著上升(P<0.01)。结论:疏肝健脾活血方能够减少肝脏炎症的发生与胶原纤维增生,抑制肝星状细胞的活化,从而起到防治肝纤维化的作用,其作用机制可能与促进IFN-γ/STAT1/Smad7信号通路有关。

Objective:To explore the possible mechanism of Shugan Jianpi Huoxue Formula in preventing and treating hepatic fibrosis.Methods:Thirty-six C57BL/6 male mice were randomly divided into normal group,model group and traditional Chinese medicine group,12 mice in each group.Except for the normal group,the other groups were treated with 20%carbon tetrachloride(CCl4)to induce liver fibrosis.The mice in the traditional Chinese medicine group were intragastrically treated with 33.3 kg/mL Shugan Jianpi Huoxue Formula for 4 weeks.The pathological changes of liver tissue of mice in each group were observed by hematoxylin-eosin staining(HE),Masson staining(Masson)and Sirius red staining(Sirius Red),distribution ofα-smooth muscle actin(α-SMA)in liver tissue was detected by immunohistochemistry,and the levels of serum alanine aminotransferase(ALT)and aspartate transarninase(AST)were detected.The expression levels of collagen typeⅠ(CollagenⅠ),α-SMA,signal transducer and activator of transcription 1(STAT1),phosphorylated signal transducer and activator of transcription 1(p-STAT1)and Smad7 in liver tissue were detected by Western Blot method,and the mRNA levels of CollagenⅠ,α-SMA,Smad7 and IFN-γin liver tissue of mice in each group were detected by RT-PCR method.Results:Compared with the model group,in the traditional Chinese medicine group,the infiltration of inflammatory cells in the liver tissue decreased,the punctate necrosis of hepatocytes decreased,the hepatocytes arranged relatively neatly,the fibrous hyperplasia in the portal area and central venous area decreased,part of the fibrous septum disappeared,and the collagen deposition decreased significantly,and the levels of ALT and AST in serum decreased significantly(P<0.01,P<0.05).The protein levels of CollagenⅠandα-SMA in liver tissue decreased significantly(P<0.05),while the levels of Smad7 and p-STAT1 protein increased significantly(P<0.05),and the levels of CollagenⅠandα-SMA mRNA in liver tissue decreased significantly(P<0.01),and the levels of Smad7 and IFN-γmRNA increased significantly(P<0.01).Conclusion:Shugan Jianpi Huoxue Formula can reduce the occurrence of hepatic inflammation and collagen fiber proliferation,inhibit the activation of hepatic stellate cells,thus play a role in the prevention and treatment of hepatic fibrosis,and its mechanism may be related to the promotion of IFN-γ/STAT1/Smad7 signal pathway.