Effects Of Ecdysterone On Free Fatty Acid-induced Fat Inflammation/JNK Signal Pathway

Abstract:Objective:Through the mouse 3T3-L1 preadipocytes' induction and differentiation, FFA induce 3T3-L1 adipocytes to set up insulin resistance model; To observe the effect of ecdysterone (EDS) on 3T3-L1 adipocytes proliferation, and further study the possible mechanisms which the EDS effect insulin resistance in vitro. Methods: The mouse 3T3-L1 preadipocytes were cultured in high glucose DMEM, containing 0.5mmol/L 3-isobutyl-l-methylxanthine (IBMX), 1μmmol/L dexamethasone, 10μg/ml insulin in DMEM (H) and 10μg/ml insulin in DMEM (H). To establish the models of insulin resistance by 3T3-L1 adipocytes were cultured in high glucose DMEM with free fatty acid;and then cultured the adipocytes with ecdysterone and the pioglitazone for 24 hours. Using Western blot and RT-PCR determine proteins and gene. At the same time determine glucose consumption for 24 hours culture solution. Experiments were divided into six groups:(1) control group: after induction of differentiation of 3T3-L1 adipocytes. (2) positive control group:the models of insulin resistance, ecdysterone. (3) EDS Group:the models of insulin resistance were cultured with different concentration of EDS (EDS1×10-7, EDS 1×10-6 and EDS1×10-5mol/L). (4) pioglitazone group.The six groups of cells were determined endoplasmic reticulum stress protein GRP78 and PERK expression using western blot;JNK1mRNA expression was determined by RT-PCR.At the same time measuring the glucose consumption of every group. Results:EDS at a concentration of＞1×10-4mol/L, the OD value decreased significantly (P＜0.01). In the EDS1×10-7 Group～EDS1×10-5 cells growth rate is 95%-100%;the expression of GRP78,PERK proteins and JNK1 gene in insulin resistance cells were increased significantly,after ecdysterone intervention, the expression them have different degrees of reduction; EDS at a concentration of 1×10-7～1×10-5, the glucose consumption of cells are increased. Conclusions:(1) Free fatty acids could activate endoplasmic reticulum stress, resulting in insulin resistance. (2) At a concentration of ecdysterone＞1×10-4mol/L, adipocytes were obvious suppressed, for this, the concentration of EDS in experiment is 1×10-7～1×10-5mol/L. (3) ecdysterone could reduces GRP78, and PERK proteinand JNK1 mRNA expression, moreover increased glucose consumption, thereby improving insulin resistance in obesity and cells.These effect spots could reveal that the 2 diabetes insulin resistance is the result of many link signals'changed and stacked.while by which ecdysterone can improve insulin resistance and increase insulin sensitivity.