Study Of The Effect And Mechanism Of Pioglitazone, Valsartan Treatment Of Nonalcoholic Fatty Liver Disease

Object:To study the effects of insulin resistance(IR),lipid metabolism and inflammatory reaction on pathoathogenesis of NAFLD by establishing rat non-alcoholic fatty liver disease(NAFLD)model with high-fat diet;to observe the effects of pioglitazone and valsartan on IR,lipid metabolism and inflammatory reaction in rats with NAFLD,and provide a reference for clinical drug treatment.Method:fifty-six male SD rats were randomly divided into normal diet group(NG,n=16),which were fed on normal diet,and high-fat diet group(HG,n=40),which were fed on high-fat diet(normal diet adding 1% cholesterol and 14%lard)。At the end of 8^thweek,8 rats were randomly drew off from each group to identify the NAFLD model,and these rats were named NG8w group and HG8w group.At the beginning of 9^thweek, all rats of HG were randomly divided into four groups:HG12w(n=8),the rats of this group were sequentially fed on high-fat diet,and were given normal sodium chloride 2ml every day for 4weeks;pioglitazone group(PG,n=8),the rats of this group were continue fed on high-fat diet, and were given pioglitazone 10mg/kg/d for 4 weeks;valsartan group(DG,n=8),the rats of this group were sequentially fed on high-fat diet,and were given valsartan 5mg/kg/d for 4 weeks;(P+D)G(n=8),the rats of this group were sequentially fed on high-fat diet,and were given pioglitazone 10mg/kg/d and valsartan 5mg/kg/d for 4 weeks.Blood pressure was monitored per day,fasted and weighed all the rats before executing.After executing,serum alanine aminotransferase(ALT),aspartate aminotransferase(AST),triglyceride(TG),total cholesterol(TC),fasting blood glucose(FBS),fasting insulin(Fins),free fatty acid(FFA)and tumor necrosis factor-α(TNF-α)were measured by drawing blood from portal vein;then,the liver was dissociated and weighed,fasting insulin resistance index(FIRI)was calculated;the liver tissues were made to 10%liver homogenate for measuring the levels of liver TG,TC,FFA.Hepatic steatosis was assessed by using H-E stain sections,the expression of NF-κB in liver tissue was detected by using immunohistochemistry method.Result:(1)Compared to the corresponding period of NG,the weight,liver index,levels of serum ALT,AST,TG,TC,FIns,FFA,TNF-α,FIRI and levels of liver homogenate TG,TC,FFA of HG were higher,there were significant statistics differences between them(p＜0.05); however there was no changes in FBS of each group;Vacuolar hepatic steatosis was observed in HG8W rats under the light microscope;the diffused hepatic steatosis and lobular inflammatory-cell infiltration were observed in HG12W rats under the light microscope;(2)Compared to NG12w rats,the liver index,levels of serum ALT,AST,TG,FIns,FFA,TNF-α,FIRI and levels of liver homogenate TG,FFA of PG and DG were lower,there were significant statistics differences(p＜0.05),but there were no statistics differences in serum and liver homogenate TC of DG and HG(p＞0.05);Compared to DG rats,the liver index,serum TG,TC,Fins,FFA and the levels of liver homogenate TG,TC,FFA of PG are lower,there were significant statistics differences(P＜0.05),but there were no statistics differences in the levels of serum ALT and AST(p＞0.05),the level of serum TNF-αand the expression of NF-κB P65 are higher,there were significant statistics differences between them(P＜0.05)。(3)Compared to PG and DG,the rat liver index,the levels of serum ALT,TG,FIns,FFA,TNF-α,FIRI,the levels of liver homogenate TG,FFA and the expression of NF-κB P65 of the(P+D)G were lower,there were significant statistics differences(p＜0.05);(4) hepatic steatosis and balloon-like changes could be observed in PG and DG under the light microscope,the lobular inflammatory-cell were also could be observed seldom,but compared to HG12w,the hepatic steatosis of PG and DG were more less;The hepatic steatosis of(P+D)G reduced in the hepatocyte,and there was no lobular inflammatory-cell infiltration.(5)FIRI had positive relationship with serum TNF-αand hepatic steatosis.Conclusion:1.The SD rat NAFLD model can be successfully established by constantly feeding high-fat diet for 8 weeks.2.Pioglitazone can improve IR,and play therapeutic role in SD rat NAFLD.3.Valsartan can improve IR,and play therapeutic role in SD rat NAFLD.4.Compared to pioglitazone,the effect of improving IR and lipid metabolism of valsartan is not as good as,but the anti- inflammatory effect is better.5.Compared to monotherapy with either drug,the curative effects of combining pioglitazone and valsartan to improve each index of NAFLD are more better,it provide a new way to treat NAFLD.