α-亚麻酸植物甾醇酯调控TGF-β1/Smad信号通路改善小鼠肝纤维化

PLANT STEROL ESTER OFα-LINOLENIC ACID IMPROVEs LIVER FIBROSIS BY REGULATING TGF-β1/SMAD SIGNALING PATHWAY IN MICE

目的探讨α-亚麻酸植物甾醇酯(PS-ALA)对高脂高胆固醇饮食(HFCD)诱导的肝纤维化的改善作用,及其抑制TGF-β1/Smad信号通路的分子机制。方法将50只雄性C57BL/6J小鼠随机分为Control、HFCD、ALA、PS和PS-ALA组,每组10只。Control组给予普通饲料;HFCD组给予高脂高胆固醇饲料(45%kcal脂肪、2%胆固醇);ALA、PS和PS-ALA组给予相同的高脂高胆固醇饲料并分别添加1.3%ALA、2%PS和3.3%的PS-ALA。24w后,Masson染色评估肝脏纤维化严重程度;试剂盒检测HYP、ALT和AST水平;免疫荧光法检测肝脏α-SMA的表达水平;Western-blot法检测肝脏TGF-β1、Smad2/3、P-Smad2、α-SMA、COL1A1及CTGF蛋白表达水平。结果与Control组相比,HFCD组小鼠肝脏组织出现大量胶原沉积,同时伴随α-SMA蛋白表达水平上调,提示肝脏纤维化发生。PS-ALA显著改善HFCD诱导的小鼠肝脏纤维化,并显著降低血清ALT、AST以及肝脏HYP水平(P<0.05);PS-ALA显著下调纤维化关键调节因子TGF-β1及其靶分子P-Smad2、COL1A1及CTGF的蛋白表达水平(P<0.05)。结论PS-ALA干预能有效改善HFCD诱导的肝纤维化,其分子机制与抑制TGF-β1/Smad信号通路有关。

Objective To investigate the effects of plant sterol ester ofα-linolenic acid(PS-ALA)on liver fibrosis induced by a high-fat and high-cholesterol diet and to explore the possible molecular mechanism in mice.Methods Fifty male C57 BL/6 J mice were randomly divided into the control,HFCD,ALA,PS,and PS-ALA groups(n=10).The control group was given a normal diet,the HFCD group a high-fat and high-cholesterol diet,the ALA,PS,and PS-ALA groups were given the same high-fat and high-cholesterol diet supplemented with 1.3%ALA,2%PS,or 3.3%PS-ALA,respectively.After 24 weeks,the severity of liver fibrosis was assessed with Masson staining while the levels of HYP,ALT,and AST were measured by commercial kits.The expression ofα-SMA in the liver was detected by immunofluorescence.The protein expressions of TGF-β1,Smad2/3,P-Smad2,α-SMA,COL1 A1 and CTGF in the liver were measured by Western blot.Results Compared with the control group,the liver tissue of the mice in the HFCD group presented a large amount of collagen deposition and significantly-increased expression ofα-SMA,suggesting the occurrence of liver fibrosis.PS-ALA intervention significantly improved liver fibrosis induced by HFCD and reduced serum ALT,AST and liver HYP(P<0.05).In addition,PS-ALA significantly reduced the protein expression of TGF-β1,which is a key fibrosis regulator,and inhibited the expressions of P-Smad2,COL1 A1 and CTGF(P<0.05).Conclusion PS-ALA can improve liver fibrosis induced by HFCD and the underlying molecular mechanism is related to the inhibition of the TGF-β1/Smad signaling pathway.