甲醛对肝细胞极低密度脂蛋白分泌外排相关基因的影响

Effects of formaldehyde on VLDL secretion-related genes in hepatocytes

目的观察甲醛对肝癌细胞株HepG2细胞内外甘油三酯(TG)含量及细胞内极低密度脂蛋白(VLDL)分泌外排相关基因表达水平的影响。方法以0、0.004、0.02、0.1 mmol/L甲醛分别处理人肝癌HepG2细胞24、48 h,采用甘油磷酸氧化酶法(GPO-POD)测定细胞内外TG含量,采用QRT-PCR法检测细胞内载脂蛋白B100(apo B100)、微粒体TG转运蛋白(MTTP)、载脂蛋白E(apo E)、TG水解酶(CES3)、二酰基甘油酰转移酶1(DGAT1)、包被蛋白Ⅱ(COPⅡ)、Sar1b、低密度脂蛋白受体(LDLR)基因的表达水平。结果与阴性对照组相比,0.004、0.1 mmol/L甲醛染毒48 h后HepG2细胞内TG含量减少,染毒24 h后上清中TG含量增加;染毒24 h后0.004、0.02、0.1 mmol/L甲醛组或染毒48 h后0.004 mmol/L甲醛组细胞内apo B100基因表达水平升高;染毒24 h后0.004 mmol/L甲醛组或染毒48 h后0.004、0.02、0.1 mmol/L甲醛组细胞内MTTP基因表达水平升高;染毒24 h后0.1 mmol/L甲醛组细胞内LDLR基因表达水平降低,染毒48 h后0.02、0.1 mmol/L甲醛组细胞内LDLR基因表达水平升高;上述差异均有统计学意义(P<0.05)。结论甲醛可能通过增加肝细胞内apo B100和MTTP表达来促进VLDL的分泌外排。

Objective To know the effects of formaldehyde （FA） on the intra and extra-hepatocellular triglyceride （TG） contents and the expression of very low density lipoprotein （VLDL） secretion-related genes in HepG2 cells. Methods HepG2 cells were treated with FA at the doses of 0.004, 0.02 and 0.1 mmol/L for 24 hours and 48 hours, respectively. The intra and extra- hepatocellular TG contents were determined by using triglyceride GPO-POD assay kit after FA exposure. The gene expression of apolipoprotein BIO0 （apoB100）, microsomal triglyceride transfer protein （MTTP）,apolipoprotein E （apoE）, carboxylesterase 3 （CES3）, diacylgycerol acyltransferase 1 （DGAT1）, coat protein comlex Ⅱ （COP Ⅱ ）, Sarlb and low density lipoprotein receptor （LDLR） in the intracellular was detected by QRT-PCR method. Results Compared with negative control group, the intra TG levels in the hepatocytes significantly decreased after exposure to 0.004 and 0.1 mmol/L FA for 48 hours and the extrahepatocellular TG contents significantly increased after exposure to 0.004 and 0.1 mmol/L FA for 24 hours （P〈0.05）. ApoBlO0 gene expression significantly increased in each FA group after 24 hours and in 0.004 mmol/L group after 48 hours exposure （P〈 0.05）. MTTP gene expression significantly increased in 0.004 mmol/L group after 24 hours and in each FA group after 48 hours exposure （P〈0.05）. LDLR gene expression significantly decreased in 0.1 mmol/L group after 24 hours exposure,increased in 0.02 and 0.1 mmol/L groups after 48 hours exposure （P〈0.05）. Conclusion Formaldehyde exposure may promote the hepatocellular VLDL secretion through increasing apoB100 and MTTP gene expressions.