The Effect Of Recombinant Adiponectin On Endoplasmic Reticulum Stress-related Proteins Induced By Oxidative Damage In Human Umbilical Vein Endothelial Cells

OBJECTIVE: To investigate the effects of recombinant adiponectin on apoptosis in Human Umbilical Vein Endothelial Cells (HUVECs) induced by tert-butyl hydroperoxide (t-BHP) .In this process, it would be further discussed the effects of recombinant adiponectin on endoplasmic reticulum stress–related proteins including inositol-requiring enzyme-1α(IRE1α) and phospho c-jun NH2-terminal kinase(p-JNK) in HUVECs.METHODS: HUVECs was cultured in vitro and induced by t-BHP with the concentrations ranging from 25 to 400μmol/L for l～24 h. MTT assay was used to measure the cell survival rate after treatment with t-BHP, the apoptotic rate was evaluated by fluorescence microsopic analysis with Hochest / PI staining. Endoplasmic reticulum stress– related proteins were detected by Western blot.Further, cells were pretreated by recombinant adenovirus with adipose most abundant gene transcript 1 prior to t-BHP exposure, the effects of apoptosis and protein levels of IRE1α, p-JNK and caspase-3 were detected.RESULTS: As HUVECs was exposed to t-BHP with the concentrations ranging from 25 to 400μmol/L for l～24 h, the viability of cells were gradually reduced in dose-dependant and time-dependant mannar. The ratio of apoptotic cells were increased gradually significantly by Hochest/PI staining when treated by t-BHP with the different concentrations 8 h. Western blot revealed upregulation of several ER stress–related proteins, including IRE1α, p-JNK and subsequently, caspase-3. AS cells were pretreated by recombinant adenovirus with adipose most abundant gene transcript 1 prior to t-BHP exposure, apoptosis rate and protein levels of p-JNK, caspase-3 were decreased significantly. And yet, no significant change in IRE1αwas expressed in this process. CONCLUSION: These studies suggested that oxidative stress mediated apoptosis in HUVECs, which might be correlated with the expressions of endoplasmic reticulum stress–related proteins, including IRE1αand JNK. Recombinant adiponectin protected HUVECs from oxidative damage induced by t-BHP, which was irrelevant to IRE1α.