狗肝菜多糖对二甲基亚硝胺诱导的肝纤维化大鼠TGF-β1/Smads信号通路的影响

Effects and mechanism of polysaccharide of Dicliptera chinensis on TGF-β1/Smads signal pathway in hepatic fibrosis rats induced by dimethylnitrosamin

目的:以二甲基亚硝胺(DMN)诱导的大鼠肝纤维化为模型,研究狗肝菜多糖对DMN诱导的肝纤维化大鼠TGF-β1/Smads信号通路的影响。方法:将96只大鼠随机分为对照组、模型组、狗肝菜多糖(300 mg/kg,200 mg/kg,100 mg/kg)组和秋水仙碱组(0.12 mg/kg)。除对照组以外,其余各组大鼠均腹腔注射0.5%DMN溶液(1.5 ml/kg),隔天1次,在首次注射DMN同时,各组大鼠灌胃给予相应的药物,而正常组和模型组灌胃给予相应体积的生理盐水溶液,每天给药1次,连续5周,5周末眼球取血,脱臼致死,收取肝脏。生化法检测血清中碱性磷酸酶(ALP)、谷氨酰氨基转移酶(GGT)水平;酶联免疫法检测(ELISA)血清中透明质酸(HA)、层黏连蛋白(LN)、Ⅲ型前胶原(PCⅢ)和Ⅳ型胶原(Ⅳ-C)含量。苏木精-伊红染色(HE染色)进行肝组织病理学检查;蛋白质印迹法(Western blot)检测肝组织a-平滑肌肌动蛋白(a-SMA)、转化生长因子β1(TGF-β1)和Smad2/3/7的蛋白表达情况。结果:与模型组比较,经狗肝菜多糖(300 mg/kg,200 mg/kg,100 mg/kg)组干预后,血清中ALP、GGT、HA、LN、PCⅢ和Ⅳ-C水平显著降低;肝组织中a-SMA、TGF-β1、Smad2/3的蛋白表达被抑制,而Smad7的表达得到促进;病理切片显示肝纤维化大鼠肝组织炎症坏死程度和肝纤维化病变程度较模型组明显减轻。结论:狗肝菜多糖具有抗DMN诱导的大鼠肝纤维化的作用,其机制与TGF-β1/Smads信号通路相关因子的表达有关。

Objective： To study the effects and mechanism of Dicliptera chinensis polysaccharide on TGF-β1/Smads signal pathway in hepatic fibrosis rats induced by dimethylnitrosamin. Methods： 96 SD rats were randomly divided into control group, model group, Dicliptera chinensis polysaceharide （300 mg/kg, 200 mg/kg, 100 mg/kg） groups and colchicines（0.12 mg/kg） group. Except the normal control group, the other rats were injected 0.5% dimethylnitrosamin solution （1.5ml/kg） through abdominal cavity, once per two days in five weeks. At the same time, the rats were injected with DMN, the normal group and model group were given the corresponding volume of saline solution, once per day the levels of serum alkaline phosphatase （ ALP）, glutamy hranspeptidasecc （GGT） were assayed. The contents of hyaluronic acid （HA） , laminin （LN） , type Ⅲ collagen （PCⅢ） and type Ⅳ collagen （Ⅳ-C） were tested by enzyme linked immunosorbent assay （ELISA） in serum. The liver tissues were done through HE. The a-Smooth muscle actin （a-SMA） ,transforming growth faetor-β1 （ TGF-β1） , Smad2, Smad3 and Smad7 were detected by Western blot. Results： Compared with the model group, the hepatic fibrosis of rats in Dicliptera chineusis polysaccharide （300 mg/kg, 200 mg/kg, 100 mg/kg） groups were improved obviously, the levels of ALP, GGT,HA, LN, PCⅢ and Ⅳ- C in serum were lowered obviously ;the expressions of a-SMA ,TGF-β1 , Smad2 and Smad3 were markedly lowed, but the expression of Smad7 was significantly higher by Dicliptera chinensis polysaccharide intervention. The pathological sections showed that the inflammation, necrosis and the degree of liver fibrosis in rats were significantly lower than that in model group. Conclusion： Dicliptera chinensis polysac-charide easied DMN induced liver fibrosis rats, the mechanism may be related with its inhibiting the expression of a-SMA , TGF-β1 ,Smad2 , Smad3 and enhancing the expression of Smad7 in livers of rats.