目的:研究茵陈醇提物对游离脂肪酸刺激HepG2细胞所致肝脂毒性的抑制作用及机制。方法:制备大鼠的正常血清和药物血清,在经毒性试验确定无药物毒性的前提下,分设正常组、模型组和茵陈醇提物组(10%,1%,0.1%3个剂量),以相应浓度的正常血清和药物血清培养HepG2细胞,同时添加长链游离脂肪酸(FFA)刺激HepG2细胞24 h。观察:①细胞上清肿瘤坏死因子(TNF-α)含量(ELISA法);②细胞内甘油三酯(TG)含量、细胞脂肪油红O染色;③细胞内磷酸化κB抑制蛋白(P-IκB)、组织蛋白酶B(ctsb)、凋亡抑制基因相关X蛋白(Bax)蛋白表达(W estern B lotting法);④细胞TNF-,αctsb和Bax基因表达(real-tim e PCR);⑤细胞内ctsb的表达和分布(免疫荧光法)。结果:模型组细胞内TG及上清TNF-α含量显著升高,分别达(590±186)mg.g-1,(77±11)pg.mg-1,细胞内ctsb,P-IκB的蛋白表达以及ctsb,TNF-α的mRNA表达显著增强;而10%茵陈醇提物组细胞内TG和上清TNF-α含量较模型组显著降低,仅为(335±54)mg.g-1,(55±7)pg.mg-1,且显著抑制细胞内ctsb,P-IκB的蛋白表达以及ctsb,TNF-α的mRNA表达。结论:茵陈醇提物对FFA诱导的HepG2细胞脂肪变性,TNF-α分泌有显著的抑制作用,其作用与抑制ctsb等基因和蛋白表达有关。
Objective： To study the experimental efficacy of Qushi Huayu Decoction （祛湿化瘀方,QHD） on protein and gene expression of cathepsin B （ctsb） in HepG2 cells induced by free fatty acids （FFAs）.Methods： The model of HepG2 steatosis and tumor necrosis factor-α （TNF-α） secretion was induced by long-chain FFAs.HepG2 cells were divided into 4 groups： control group （group C）,model group （group M）,low-dose QHD group （group L） and high-dose QHD group （group H ）.Long-chain FFAs were added to groups M,L and H.The 10% blank-control serum was added to group C and M,while 5% and 10% QHD-containing sera were added to group L and H,respectively.The levels of serum TNF-α and cellular triglyceride （TG） were detected.Cellular p-IκB and ctsb expression were detected using Western blot and PCR.The expression and distribution of ctsb were observed by immunofluorescence.Results： After incubating with FFA for 24 h,TG deposition in HepG2,TNF-α content in cell supernatant,the protein expression of cellular ctsb and P-IκB,as well as mRNA expression of ctsb increased markedly in group M compared with group C （P〈0.05,P〈0.01）.Compared with group M,TG deposition,the expression of cellular ctsb,P-IκB and ctsb mRNA in groups L and H,as well as TNF-α content in group H,decreased significantly （P〈0.05）.Cell immunochemical fluorescence studies showed that ctsb was released from lysosomes and distributed in the cytoplasm extensively and diffusedly after being stimulated with FFA.In this study,these above-mentioned changes were inhibited markedly in groups L and H.Conclusion： QHD might have a direct inhibitory effect on the ctsb target in the FFA-ctsb-TNFα pathway of hepatic lipotoxicity.
