头顶一颗珠提取物对非酒精性脂肪肝大鼠的治疗作用及其机制

Therapeutical effect of Toudingyikezhu extract on rats with nonalcoholic fatty liver and its mechanism

目的:探讨头顶一颗珠提取物对非酒精性脂肪肝(NAFLD)大鼠肝脏形态和内质网应激(ERS)的影响,阐明头顶一颗珠提取物干预NAFLD的可能机制。方法:四氯化碳溶液腹腔注射联合高脂饮食建立NAFLD大鼠模型。60只大鼠随机分为正常组,模型组,低、中和高剂量头顶一颗珠提取物组,多烯磷脂酰胆碱组(n=10)。低、中和高剂量头顶一颗珠提取物组提取物用药浓度分别为0.50、1.00和2.00g·mL^(-1),多烯磷脂酰胆碱组用药浓度为0.2g·kg^(-1)。用药4周,实验结束称取大鼠体质量和肝湿重,计算肝指数;HE染色观察大鼠肝脏的质地弹性、颜色和形态;计算大鼠肝脏脂肪变性、炎症及坏死积分;ELISA法测定大鼠血清肿瘤坏死因子α(TNF-α)、白细胞介素1(IL-1)和白细胞介素6(IL-6)水平;免疫组织化学(SP)法观察大鼠肝脏GRP78蛋白表达水平;PCR法检测大鼠肝组织中GRP78 mRNA表达水平。结果:与正常组比较,光镜下模型组大鼠肝脏形态结构明显异常,肝指数、肝脏脂肪变性、炎症和坏死积分升高(P<0.05),GRP78蛋白和mRNA表达水平降低(P<0.01);与模型组比较,各剂量头顶一颗珠提取物组大鼠肝脏肉眼及微观形态不同程度好转,肝脏脂肪变性、炎症及坏死积分、血清TNF-α、IL-1和IL-6水平不同程度降低(P<0.05或P<0.01),肝组织中GRP78蛋白及mRNA表达水平升高(P<0.05或P<0.01)。结论:头顶一颗珠提取物可能过下调大鼠肝组织ERS通路相关分子GRP78的表达抑制或阻断ERS,从而减少脂质合成,加速其分解,发挥抗NAFLD大鼠肝细胞损伤的作用。

Objective：To observe the effect of Toudingyikezhu extract on the morphology of liver tissue and endoplasmic reticulum stress（ERS） of the rats with nonalcoholic fatty liver disease（NAFLD）,and to clarify the possible mechanism of Toudingyikezhu of intervention of NAFLD.Methods：The NAFLD rat models were established by intraperitoneal injection of carbon tetrachloride solution combined with high-fat diet.A total 60 SD rats were randomly divided into control group,model group,low,middle and high doses of Toudingyikezhu extract groups,phosphatidylcholine group（n=10）.The doses of Toudingyikezhu extracts were 0.50,1.00 and 2.00 g·mL^-1,and the dose of phosphatidylcholine was 0.20 g·kg^-1,4 weeks after administration,the body weights and liver wet weights were detected,and the liver indexes were calculated.The texture,elasticity,color and morphology of liver tissue of the rats were observed by HE staning.The fatty degeneration,inflammation and necrosis scores of liver tissue of the rats were calculated.The levels of serum tumor necrosis factor-α（TNF-α）,interleukin-1 （IL-1） and interleukin-6（IL-6） of the rats were detected by ELISA method.Immunohistochemical SP method was used to determine the expression levels of GRP78 protein,and PCR method was used to determine the expression levels of GRP78 mRNA.Results：Compared with control group,the morphology of liver tissue of the rats in model group were abnormal under light microscope;the liver index,fatty degeneration,inflammation and necrosis scores of liver tissue of the rats in model group were increased（P〈0.05）,and the expression levels of GRP78 protein and mRNA were decreased（P〈0.01）.Compared with model group,the liver tissue pathology of the rats had different degrees of improvement;the fatty degeneration,inflammation and necrosis scores of liver tissue and the serum TNF-α,IL-1,IL-6 levels of the rats in different doses of Toudingyikezhu extract groups were decreased（P〈0.05 or P〈0.01）;the expression levels of GRP78 protein and mRNA were decreased （P 〈0.05 or P〈0.01）.Conclusion：Toudingyikezhu extract may inhibit or block the ERS,reduce the synthesis of lipids and accelerate its decomposition in order to resist the injury of liver cells of the NAFLD rats by down-regulating the GRP78 expression.