Objective To investigate the molecular biological mechanism of deposition of triglyceride(TG)in hepatocytes in alcoholic fatty liver disease(AFLD)and the pathogenesis of this condition by detecting the contents of serum tumor necrosis fac-tor-α(TNF-α),liver triglyceride(TG),peroxisome proliferator-activated receptorα(PPARα)and acyl-CoA oxidase(Acox1)mR-NAs,and liver PPARαprotein after intervention with bezafibrate,a PPARαagonist.Methods Sixty Wistar rats were randomly divided into three groups:control group(n=20),AFLD group(n=20),and bezafibrate group(n=20).Animals in control group were given distilled water by gavage once a day for 8 weeks.Those in AFLD group were given ethanol and fish oil(2.5 mL/kg) by gavage daily for the same period of time.In bezafibrate group,rats were treated by gavage with ethanol and fish oil(2.5 mL/kg)for the first 4 weeks and then with bezafibrate(100 mg/kg)for another 4 weeks.TG in the liver was measured by colorimet-ric method,serum TNF-αlevels by enzyme linked immunoabsorbent assay (ELISA),the mRNA expression of PPARαand Acox1 in hepatocytes by reverse transcription polymerase chain reaction(RT-PCR)and the expression of PPARαprotein in hep-atocytes by Western blot.Results A significant increase in TG[AFLD group(0.72±0.09)mmol/L vs.control group(0.28± 0.07)mmol/L,P<0.01]and TNF-α[AFLD group(3.01±0.31)ng/mL vs.control group(1.07±0.28)ng/mL,P<0.01]was found in AFLD group when compared with control group.After bezafibrate intervention,the contents of liver TG and serum TNF-αwere significantly decreased.The mRNA expression of PPARα[AFLD group(0.22±0.08)vs.control group(0.68± 0.13),P<0.01]and Acox1[AFLD group(0.43±0.12)vs.control group(1.14±0.21),P<0.01]was suppressed in AFLD group,which was significantly reversed by bezafibrate treatment[bezafibrate group(0.59±0.13)for PPARαmRNA vs.AFLD group,P<0.01;bezafibrate group(0.83±0.17)for Acox1 mRNA vs.AFLD group,P<0.01].The expression of PPARαpro-tein in hepatocyts was also found to decrease in AFLD group[AFLD group(0.19±0.07)vs.control group(0.48±0.11),P<0.01].After bezafibrate intervention,it was profoundly increased.Conclusion The down-expression of PPARαand Acox1 in the liver of rats with AFLD may suppress the fatty acid metabolism and lead to the TG deposition in the liver.The increase in serum TNF-αcontents also contributes to the development of AFL.Bezafibrate can prevent and treat AFL by activating PPARα,increasing the expression of PPARαand Acox1 ,promoting the metabolism of fatty acids,decreasing the TG deposition and the serum TNF-αcontents.%目的：通过测定酒精性脂肪肝大鼠血清 TNF-α、肝内甘油三酯、PPARαmRNA 及 Acox1 mRNA 含量、肝内PPARα蛋白含量,并通过PPARα激动剂苯扎贝特(Bezafibrate)的干预研究,探讨酒精性脂肪肝大鼠肝内甘油三酯沉积的分子生物学机制及酒精性脂肪肝的发病机制。方法将60只 Wistar大鼠随机分为正常对照组(n=20)、酒精性脂肪肝组(n=20)及苯扎贝特组(n=20)。正常对照组予蒸馏水灌胃8周；酒精性脂肪肝组给予鱼油2.5 mL/kg+乙醇灌胃8周；苯扎贝特组采用鱼油+乙醇灌胃,4周后加用苯扎贝特100 mg/kg灌胃治疗4周。第8周取腹腔静脉血及肝组织,采用 ELISA法测定血清TNF-α含量；比色法测定肝脏甘油三酯沉积；RT-PCR 法测定肝内 PPARαmRNA 及 Acox1 mRNA含量；Western blot法测定肝内PPARα蛋白含量。结果与正常对照组相比,酒精性脂肪肝组大鼠血清内TNF-α含量升高[(3.01±0.31)ng/mL vs.(1.07±0.28)ng/mL,P<0.01],肝内甘油三酯沉积增多[(0.72±0.09)mmol/L vs.(0.28±0.07)mmol/L,P<0.01],肝内PPARαmRNA[(0.22±0.08)vs.(0.68±0.13),P<0.01]及 Acox1 mRNA [(0.43±0.12)vs.(1.14±0.21),P<0.01]表达减少,PPARα蛋白含量减少[(0.19±0.07)vs.(0.48±0.11),P<0.01]。经苯扎贝特治疗后,苯扎贝特组大鼠血清内 TNF-α含量降低,肝内甘油三酯沉积减少,肝内 PPARαmRNA 及Acox1 mRNA表达增多,PPARα蛋白含量增多。结论酒精性脂肪肝大鼠肝内 PPARα及 Acox1表达减少,从而影响脂肪酸的代谢,导致肝内甘油三酯沉积增多,血清内 TNF-α含量升高,引起酒精性脂肪肝。苯扎贝特可通过激活PPARα,使肝内PPARα及 Acox1表达增加,促进脂肪酸的代谢,减少肝内甘油三酯沉积,降低血清内 TNF-α含量,起到预防和治疗酒精性脂肪肝的作用。
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