Effects of carbon tetrachloride on triglyceride content in HL-7702 liver cells

Objective To observe the effects of carbon tetrachloride (CCl₄)on triglyceride (TG)level and the change of very low density lipoprotein (VLDL)secretion in hepatocytes.Methods Human diploid liver cells (HL-7702),cultured in Dulbecco's modified Eagle's medium (DMEM)containing 10% fetal bovine serum,were divided into 3 groups:negative control,10 mmol/L CCl₄ and positive control (1 mmol/L oleic acid).After 24 and 48 hours,TG content was detected with glycerol-phosphate oxidase-peroxidase (GPO-POD)assay.Western blott was used to detect secretion of VLDL and protein expressions of microsomal triglyceride transfer protein (MTP),diacylglycerol acyltransferase 2(CDGAT2),and carnitine palmitoyl transferase IA(CPTIA)in hepatocytes.ApoB100 secretion was detected with enzyme-linked immunosorbent assay (ELISA).Results After 24 hours' exposure,CCl₄ increased TG level significantly(3.2353±1.1168 mmol/g prot for CCl₄ group vs 1.2218±0.5272 mmol/g prot for negative control group),(P<0.05).VLDL secretion was not changed.After exposure of 24 hours and 48 hours,the protein levels of MTP and DGAT2 in the CCl₄ treated group were higher than those of negative control group;the expression of CPT1 in 48 hours exposure group was significantly lower than that of the control.The ApoB100 protein levels in culture medium of CCl₄ treated groups (231.79,263.33 ng/mL for 24 hours and 48 hours)were significantly higher in comparison with the negative control group(135.12,143.59 ng/mL)(P<0.05).Conclusion CCl₄ may increase TG level in hepatocytes by increasing DGAT2 expression,and enhance the secretion of ApoB100 by increasing MTP expression in normal hepatocytes.