The Role Of Endoplasmic Reticulum Stress Involves In Elaidic Acid-induced Insulin Resistance In Human Adipocytes

Objective: To observe the effects of endoplasmic reticulum stress mediated on insulin resistance in human mature adipocytes induced by elaidic acid exposure.Methods: Human adipose-derived mesenchymal stem cells were cultured in vitro to induce differentiation into mature adipocytes.It was exposed to 100 ?mol/L of elaidic acid(EA)and its isomer oleic acid(OA)for 24 h.Western blot was used to analyze the expression of serine protein in insulin receptor substrate-1 and glucose transporter4.The ultrastructural changes of human mature adipocytes were observed by transmission electron microscope.Finally,Western blot was used to detect the expression of endoplasmic reticulum stress markers(immunoglobulin heavy chain-binding protein,inositol requiring er-to-nucleus signal kinase 1-?,c-Jun N-terminal kinase).The adipocytes were incubated in the endoplasmic reticulum stress inhibitor 4-phenylbutyrate(4-PBA)for 2 h,and then exposed to elaidic acid(EA)for 24 h to extract total cellular protein.The expression level of endoplasmic reticulum stress-related protein and insulin receptor substrate-1 serine protein was again detected by Western blotting.Results: Phosphorylation of insulin receptor substrate-1 in 100 ?mol/L EA group was observed after exposure of human mature adipocytes to 100 ?mol/L of oleic acid(EA)and its isomer oleic acid(OA)for 24 h.The proportion was significantly higher than the vehicle group(1‰DMSO),and the difference was statistically significant(P<0.01).By detecting glucose transporter 4,the results showed that 100 ?mol/L EA exposure had no effect on the glucose transport capacity of human mature adipocytes(P>0.05).Under the transmission electron microscope,the endoplasmic reticulum of human mature adipocytes in the 100?mol/L EA exposed group was expanded and expanded into a pool.Compared with the vehicle group,100?mol/L OA exposure did not cause significant changes in endoplasmic reticulum stress-related protein expression;while 100?mol/L EA exposure resulted in significant differences in endoplasmic reticulum stress-related protein expression and the difference was statistically significant(P<0.05).After treatment with endoplasmic reticulum stressinhibitor 4-phenyl butyric acid(4-PBA),the expression levels of endoplasmic reticulum stress markers in the EA+4PBA exposed group were down-regulated compared with the EA-exposed group(P<0.05),the ratio of serine protein phosphorylation of insulin receptor substrate-1 was also decreased(P<0.05),and the difference was statistically significant.Conclusion: Exposure to elaidic acid caused insulin resistance in mature adipocytes,which may be mediated by endoplasmic reticulum stress.