| Arachidonic acid(AA)produces epoxide eicosetrienoic acid(EETs)and 20-hydroxy eicosatetraenoic acid(20-HETE)via Cytochrome P450(CYP)epi-oxidase pathway.These metabolites play an important role in cell growth and differentiation,regulating body temperature and blood pressure.In addition,these metabolites play a significant role in a range of human major diseases,such as diabetes.With the further exploration of AA and its metabolites,more attention has been paid to the role of AA and its metabolites in the function of islet β cells and insulin resistance.The aim of this study was to investigate the effects of AA cytochrome P450 epi-oxidase metabolites EETs and 20-HETE on the proliferation and insulin secretion of islet 3 cells,and to provide a theoretical basis for the prevention and treatment of type 2 diabetes mellitus.In this study,islet β cells cultured in vitro were taken as the object of study.After cell culture,passage and living cell counting,islet β cells were treated with different concentrations of EETs and 20-HETE,the effects of EETs and 20-HETE/EETs on the proliferation of pancreatic islet cells were detected by CCK-8 method at the time of culture to 12h,24h and 48h;The mechanism of the effect of EETs and 20-HETE/EETs on the proliferation of islet β cells was detected by WB;ELISA was used to detect the effect and mechanism of EETs and 20-HETE/EETs on insulin secretion by islet β cells.The results showed that:(1)At 12h and 24h,14,15-EET at a concentration of 100 nM significantly promoted the proliferation of islet β cells,the difference was the most significant at 12 hours,there was no significant difference in other concentrations of EETs and 20-HETE.At 48h,there was no significant difference among the groups.(2)The expression level of PI3K in EETs-treated group was significantly higher than that in control group,when 20-HETE/EETs is combined,the expression level of PI3K decreased significantly;The level of PI3K expression was significantly inhibited in the inhibitor treatment group,however,the expression level of phosphorylated AKT was significantly increased;there was no significant difference in the expression of PI3K protein between 11,12-EET and 14,15-EETs.(3)At 12h,24h and 48h,11,12-EET and 14,15-EET all significantly enhanced the ability of islet beta cells to secrete insulin,the most significant was at 48h.Among them,the effect of 11,12-EET was slightly dominant.1:10 20-HETE/11,12EET group had a significant effect on insulin secretion of islet β cells at 12h,However,there was no significant effect at 24h and 48h.The 20-HETE/14,15EET group showed no significant difference in the three time periods.(4)At 12h and 24h,the insulin levels in the 11,12-EET group and the 14,15-EET group increased significantly,there was no significant increase in insulin content in the 20-HETE/11,12-EET group and the 20-HETE/14,15-EET group.The 11,12-EET and 14,15-EET groups were compared with the corresponding inhibitor groups,and the differences were significant.At 48h,Insulin levels were significantly increased in the 11,12-EET,14,15-EET,20-HETE/11,12-EET,and 20-HETE/14,15-EET groups.The 11,12-EET,14,15-EET,20-HETE/11,12-EET and 20-HETE/14,15-EET groups were compared with the corresponding inhibitor groups,the differences are significant.Research shows,14,15-EET at a concentration of 100 nM promoted the proliferation of islet β cells in a time-dependent manner;11,12-EET and 20-HETE/EET have no significant effect in promoting islet beta cell proliferation.Both 11,12-EET and 14,15-EET significantly enhanced the ability of islet beta cells to secrete insulin,among them,11,12-EET has a slight advantage.20-HETE/EET had no significant effect on the ability of islet beta cells to secrete insulin.11,12-EET and 14,15-EET may promote insulin secretion of islet β cells through PI3K signal transduction pathway.These conclusions indicate that 11,12-EET and 14,15-EET play an important role in islet beta cell proliferation and insulin secretion. |
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