Effects Of Formaldehyde On Gene Expressions Related Lipid Metabolism In Hepatocytes

Objective:To investigate the possible mechanism of formaldehyde induced liver injury by observing the effects of formaldehyde(FA)on the intra and extra-hepatocellular triglyceride(TG)and free cholesterol(FC)contents and the expressions of lipid metabolism related gene in HepG2 cells.Methods:HepG2 cells were treated with FA by 0.004,0.02 and 0.1 mmol/L concentrations for 24 h and 48 h.The intra and extra-hepatocellular TG and FC contents were determined using POD assay kit after FA exposure.The expressions of gene related to TG metabolism: sterol regulatory element-binding protern 1(SREBP-1),diacylgycerol acyltransferase 2(DGAT2),peroxisome proliferator activated receptor ?(PPAR?),carnitine palmitoyl transferase 1(CPT1),microsomal triglyceride transfer protein(MTTP),apolipoprotein B100(apoB100),apolipoprotein E(apoE),carboxylesterase 3(CES3),diacylgycerol acyltransferase 1(DGAT1),coat protein comlex ?(COP?),Sar1 b and related to FC metabolism: sterol regulatory element-binding protern 2(SREBP-2),SREBP cleavage-activating protein(SCAP),insulin-induced gene 1(Insig1),3-hydroxy-3-methylglutaryl-CoA reductase(HMGCR),low density lipoprotein receptor(LDLR)in the intracellular was detected by QRT-PCR method.Results:Part ?:(1)Compared with negative control group,the intra TG levels in the hepatocytes were significantly decreased after exposure to each FA group for 48 h and the extra-hepatocellular TG contents were significantly increased after exposure to each FA group for 24 h(P<0.05).(2)Compared with negative control group,PPAP? gene expression was significantly decreased in each FA group after 48 h exposure(P<0.05).CPT1 gene expression was significantly decreased in 0.004 mmol/L FA after 24 h and in 0.01 mmol/L FA after 48 h exposure(P<0.05).(3)Compared with negative control group,MTTP gene expression was significantly increased in 0.004 mmol/L FA after 24 h and in each FA group after 48 h exposure(P<0.05).ApoB100 gene expression was significantly increased in each FA group after 24 h and in 0.004 mmol/L FA after 48 h exposure(P<0.05).Part ?:(1)Compared with negative control group,the intra FC levels in the hepatocytes were significantly decreased after exposure to each FA group for 24 h and 48 h(P<0.05).The extra-hepatocellular FC contents were significantly decreased after exposure to 0.004 and 0.02 mmol/L FA for 48 h(P<0.05).(2)Compared with negative control group,HMGCR gene expression was significantly increased in each FA group after 24 h and decreased in 0.1 mmol/L FA after 48 h exposure(P<0.05).(3)Compared with negative control group,LDLR gene expression was significantly increased in 0.02 and 0.1 mmol/L FA after 48 h exposure(P<0.05).Conclusion:(1)Formaldehyde exposure may inhibit the hepatocellular fatty acid beta oxidation through decreasing PPAR? and CPT1 gene expressions and promote VLDL secretion through increasing apoB100 and MTTP gene expressions.(2)In the short term,formaldehyde exposure may promote the hepatocellular synthesis FC through increasing HMGCR gene expression.With the prolongation of time formaldehyde exposure may elevate the intracellular FC level through increasing LDLR gene expression,and feedback to inhibit HMGCR gene expression.The Fund Program for the Scientific Activities of Selected Returned Overseas Professionals in Shanxi Province "Formaldehyde effects on liver fat metabolism and its possible mechanism(Number: 2014-376)".