Intervention of Catalpol on High-fat Diet Induced Nonalcoholic Fatty Liver Disease in Mice / 中国医学科学院学报

ABSTRACT

To investigate the effect of catalpol on high-fat diet(HFD)-induced nonalcoholic fatty liver disease(NAFLD)and its underlying molecular mechanisms. Sixty C57BL/6J male mice were randomly divided into six groups:control group;HFD group;HFD+catalpol(100 mg/kg)group;HFD+catalpol(200 mg/kg)group;HFD+catalpol(400 mg/kg)group;and HFD+atorvastatin calcium(ATC)(30 mg/kg)group.The control group was fed a normal diet containing 4.4 kJ/g fat,whereas the other five groups were fed a high-fat diet containing 19.8 kJ/g fat.Mice in the catalpol or ATC treatment groups were administered by gavage for different doses of catalpol or ATC,whereas other mice were treated with saline.Body weight was measured once a week.Experiments were terminated after 18 weeks,and blood and liver samples were collected after an overnight fast(12 hours)for analysis.The body weight and liver weight were measured and the levels of serum total cholesterol(TC),triglyceride(TG),high-density lipoprotein cholesterol(HDL-C),low-density lipoprotein cholesterol(LDL-C),alanine aminotransferase(ALT),and aspartate transaminase(AST)as well as inflammatory factors tumor necrosis factor-α(TNF-α),interleukin(IL)-1β,and IL-6 were determined by commercially available kits.Liver sections were stained with Oil Red O and HE to investigate the lipid accumulation and histopathological changes.The protein expressions of nuclear factor kappa-B(NF-κB)p65,inhibitor of nuclear factor kappa-B α(IκBα),B-cell lymphoma-2(Bcl-2),Bcl-2 associated x protein(Bax),and Caspase-3 were determined by Western blot. Compared to the model group,the body weight gains(all =0.001),liver index(=0.008,=0.001,=0.001),ALT(=0.004,=0.001,=0.001),and AST(=0.008,=0.001,=0.001)were significantly decreased in catalpol treatment groups,and the serum levels of TC(=0.005,=0.001),TG (all =0.001),and LDL-C(all =0.001)were also significantly decreased in middle and high dose groups,and the serum level of HDL-C was significantly increased in high group(=0.009).Moreover,compared to the model group,the degree of liver injury and lipid accumulation were obviously decreased in the catalpol treatment groups according to the pathology.Similarly,the release of inflammatory factors was significantly inhibited by the treatment with catalpol.The results of Western blot showed that the protein levels of NF-κB p65(=0.014,=0.001,=0.001)and Caspase-3(all =0.001)in the livers of HFD-fed mice were significantly reduced by catalpol treatment.In addition,the protein level of IκBα(=0.028,=0.001,=0.001)and the ratio of Bcl-2/Bax in high dose group(=0.003)was increased by treatment with catalpol. Catalpol can effectively improve the body weight gains,liver index,dyslipidemia,and lipid accumulation in HFD-fed mice and inhibit the release of inflammatory factors and hepatocyte apoptosis,thereby preventing the development of NAFLD induced by HFD.