N-乙酰半胱氨酸对实验性肝硬化大鼠肝纤维化与脂质过氧化的影响

目的:探讨N-乙酰半胱氨酸(NAC)对肝硬化大鼠的作用及其影响肝纤维化与脂质过氧化损伤的机制。方法:雄性Wistar大鼠36只,随机分成正常组(7只)、模型组(14只)、NAC组(15只)。以10μL·kg~(-1)剂量二甲基亚硝胺(DMN)腹腔注射,每周连续3d,每日1次,共4 wk,诱导大鼠肝硬化模型。成模后,NAC组以NAC 0．1 g·kg~(-1)灌胃,每日1次,共4 wk;模型组给予等量生理盐水灌胃。HE染色与天狼猩红染色观察肝组织炎症与胶原沉积;水解法测定肝组织羟脯氨酸含量;生化法检查血清肝功能指标[丙氨酸转氧酶(ALT)、天冬氨酸转氨酶(AST)、总胆红素(TBil)、清蛋白(Alh)等],肝组织超氧化物歧化酶(SOD)活性与丙二醛(MDA)含量;Western印迹法检测肝组织α-平滑肌肌动蛋白(α- SMA)与热休克蛋白47(HSP47)表达。结果:治疗4 wk后,模型组大鼠死亡7只,NAC组死亡3只, NAC明显提高肝纤维化大鼠的生存率(P＜0．01)。与正常组相比,模型大鼠肝脏肝细胞变性、坏死明显,炎性细胞浸润,胶原沉积并形成假小叶;血清ALT、AST和TBil升高,AIb下降;肝组织羟脯氨酸与MDA含量升高,SOD活性下降(P＜0．01)。而NAC可显著减轻肝脏炎症、肝细胞坏死与肝组织胶原沉积,改善模型大鼠异常的肝功能指标,降低肝组织羟脯氧酸与MDA含量,提高SOD活性(P＜0．05,P＜0．01),抑制模型大鼠肝组织HSP47与α-SMA蛋白的表达(P＜0．01)。结论:N-乙酰半胱氨酸有良好的治疗肝硬化作用,其作用机制与促进肝纤维化逆转及抗肝脏脂质过氧化有关。

Effects of N-acetylcysteine on liver fibrosis and lipid peroxidation in cirrhotic rats

AIM:To explore the effects of N-acetylcysteine(NAC)on liver fibrosis and lipid peroxida- tion of liver cirrhosis in rats.METHODS:Thirty-six Wistar rats were randomized into 3 groups:normal group (7),model control group(14),and treatment group(15).The liver cirrhotic model was induced by continu- ous ip dimethylnitrosamine(DMN)10μL·kg~(-1)3 times per week for 4 wk.After model establishment,the NAC treated group orally took NAC with a dose of 0.1 g.kg-(-1),once a day for 4 wk,while the normal and model control groups took the same volume of saline.The hepatic inflammation and collagen deposition were checked with HE and sirius red staining.The serum parameters of liver function(ALT,AST,Alb,T.Bil)were assayed with the kits,hepatic hypdroxyproline content was assayed with Jamall's method,malondialdehyde(MDA) and the activities of superoxide dismutase(SOD)were measured with the kits,and protein expressions ofα- SMA,HSP47 were analyzed with Western blotting.RESULTS:After treated for 4 wk,7 rats were dead in model control group,while only 3 dead in NAC treatment group,and NAC improved the survival rate of cirrhotic rats(P＜0.01).Compared with normal rats,the model control rats had obvious liver inflammation and formed the hepatic pseudolobule due to collagen deposition,with higher level of serum ALT,AST and TBil, but lower serum Alb;the model control group also had increased hydroxyproline and MAD contents,and decreased SOD activity(P＜0.01),Compared with the model control,NAC treatment remarkably attenuated the Liver inflammination and collagen deposition,decreased the serum ALT,AST and TBil,decreased the hepatic hydroxyproline and MDA,down-regulated the protein expressions ofα-SMA and HSP47,but increased the Alb content and improved the SOD activity(P＜0.05 or P＜0.01).CONCLUSION:N-acetylcysteine had therapeutic effects on liver cirrhosis,and may exerted the action through improving the hepatic lipid peroxida- tion and the reversion of liver fibrosis.