Effects Of 2,4-dichlorophenoxyacetic Acid On Glucose Metabolism In HepG2 Cells And The Mechanism

Objective:2,4-Dichlorophenoxyacetic acid(2,4-D)is one of the most widely used herbicides in the world and often applied in vegetable crops,fruits,pastures,meadows,Forests,aquatic plants and so on.2,4-D has been found in house dust,streams and drinking water.Therefore,the effect of 2,4-D on organisms is increasingly got people's attention.There have been reports on cytotoxicity,neurotoxicity and reproductive toxicity,few studies were on glucose metabolism.The National Health and Nutrition Examination survey showed that 2,4-D can affect the metabolism of lipids and glucose which result in the lipid peroxidation damage and involved in the mechanism of acute myocardial infarction and type 2 diabetes.The aim of this study was to investigate the effect of 2,4-D on glucose metabolism in HepG2 Cells and the mechanism deeply.Methods:HepG2 cells were exposed to 2,4-D for 24 hours.We used the method of glycogen PAS staining,glucose ELISA,oil red O staining to evaluate the influence of 2,4-D exposure to the glucose metabolism and lipid metabolism in HepG2 cells.At the same time,we used the real-time quantitative PCR to detect the expression of genes of glucose metabolism and the expression of nuclear receptor gene.The western blotting and immunofluorescence were used to compare the expression of protein of glucose metabolism before and after the knockdown of the receptor in HepG2 cells.Results:Glycogen accumulation was observed obviously while the lipid accumulation was not found in HepG2 cells compared to the control after exposed to 2,4-D.The expression of glucose metabolism-related genes FoxO1,CREB and TORC2 was significantly higher than that in control after the exposure of 2,4-D while only the increase of FoxO1 and CREB was found statistically significant.The expression of receptors showed that the PPAR? increased the most with statistically significant.The results of immunofluorescence and western blotting also showed that the expression of FoxO1 and CREB were significantly increased compared to the control after exposure.After the knockdown of PPAR? receptor,we did not observed the glycogen accumulation in HepG2 cells of the exposed group compared to the control.Conclusion:2,4-D can affect the glucose metabolism in HepG2 cells and the effect can be mediated by PPAR? receptor.