Effect Of Oxidative Damage On The Expression Of Endoplasmic Reticulum Stress-Ralated Protein And Adiponectin , MCP-1,PAI-1 In 3T3-L1 Adipocytes

AIMS:Oxidative damage and ROS induced adipocyte dysfunction,which play a significant role in the pathogenesis of insulin resistance. so we observed the effects of the oxidant t-BHP on the expression of endoplasmic reticulum stress- related protein (BIP,p-IRE1a,p-JNK) and adipokines(adiponectin ,MCP-1 ,PAI-1) in 3T3-L1 adipocytes. And in addition, we studied the possible mechanisms of adipocytes dysfunction because of oxidative damage.METHODS:3T3-L1 pre-adipocytes were differentitative into adipocytes. At 24 h after exposure to t-BHP at concentrations ranging from 100 to 500μmol/L for 10min,Cell viability was determined by Methylthiazole tetrazolium (MTT). Western Blot was performed to determine the pretion levels of the signaling transduction pathways participating in ERs,such as BIP,p-IRE1a and p-JNK,at different time points(0,15,30,60,120min).The mRNA level of adiponectin, MCP-1 and PAI-1was measured by quantitative real-time reverse transcription -polymerase chain reaction (Real Time-PCR)at different time points(2,4,8,12,24h).RESULTS:①t-BHP(500μM,10min) induced BIP and phosphorylation of IRE1a at the point time of 15min,JNK was markedly phosphorylated at 30min after exposure to t-BHP for 10min.②Quantitative real-time PCR demonstrated that the mRNA levels of adiponectin was down-regulated dose-dependently.In contrast to adiponectin, the gene expression of the MCP-1 and PAI-1 were markedly elevated and in a dose-dependent manner. Compared to control group, adiponection mRNA decreased to 88% (P<0.05) at 100μM t-BHP,MCP-1 and PAI-1 mRNA increased to 127% and133% respectively, while the concentrate reached 500μM , a 57%(P<0.01) decrease in the mRNA level of adiponectin was observed, conversely,a significant 285% (P<0.01)increase in MCP-1 mRNA and a 305 % increase (P<0.01)in PAI-1 mRNA.③a time-course manner in adiponectin ,MCP-1 and PAI-1 mRNA expressions after 10-min exposure to 500μM t-BHP. the adiponectin mRNA level was down-regulated to 53% (P<0.01)at 8h and 14% (P<0.01)at 24h after exposure to t-BHP for 10min, Significant increase in MCP-1(683%) (P<0.01)and PAI-1(539%)(P<0.01) mRNA levels after 4h treatment with t-BHP for 10min.CONCLUSION: Oxidative damage actived endoplasmic reticulum stress -related protein,decreased gene expression of adiponectin and increased MCP-1, PAI-1 mRNA expression,all of which could result in adipocytes dysfunction.