Effects Of Endomorphins On Function And Mechnism Of Human Umbilical Endothelial Cell Under High Glucose

Objective 1. To investigated the effects of EM1/EM2 on apoptosis under high glucose in cultured human umbilical vein endothelial cells (HUVECs);2. To investigated the effects of EM1/EM2 on the expression of nitric oxide (NO) and endothelin-1 (ET-1) under high glucose in HUVECs;3. To investigated the effects of EM1/EM2 on the possible mechanism under high glucose in HUVECs.Methods HUVECs were isolated from freshly collected umbilical cords. Then, they were randomly divided into normal group, high glucose group, EMI-treated groups and EM2-treated groups, which were pretreated with EM1/EM2 for 2h and then stimulated with high glucose (30mM), Nal-treated groups, which were pretreated with Nal for 2h and then stimulated with high glucose (30mM) and EM1/EM2 for different designed time.PI AnnexinV-FITC detection was performed to evaluate the apoptosis rate.Levels of nitric oxide (NO) and endothelin-1 (ET-1) were measured by the Griess reaction and enzyme-linked immunosorbent assay (ELISA), respectively. Nitric oxide synthase(NOS) activity was evaluated by conversion of 3H-arginine to 3H-citrulline.mRNA expression of endothelial nitric oxide synthase(eNOS) and ET-1 were measured by real-time quantitative RT-PCR.Results Compared to the normal group, high glucose could induce apoptosis, the concentration of NO was increased at 24 h and then was significantly decreased at 48h, which were consistent with changes in NOS activity and mRNA eNOS expression, the concentrations of ET-1 were increased at 24 h or 48h, enhanced ET-1/NO ratio. Compared to the high glucose group, EM1/EM2 inhibited cell apoptosis, inhibit the effect of high glucose on the NO secretion of HUVECs, accompanied with regulating NOS activity and eNOS mRNA expression. In addition, EM1/EM2 decreased the ET-1 generation and mRNA ET-1 expression in HUVECs under high glucose, decreased ET-1/NO ratio. Compared to the EMs-treated groups, the levels of eNOS mRNA could be increased markedly by naloxone.Conclusion The results suggest that EM/EM2 have a beneficial effect in protecting against the endothelial dysfunction by high glucose in vitro, and these effects may be closely related with the opioid receptors in HUVECs.