Protective effect of Zinc on oxidative stress in vascular endothelial cells induced by uremic serum and its possible mechanism

Abstract:

Objective：To investigate the protective effect of Zinc on oxidative stress in vascular endothelial cells induced by uremic serum and its possible mechanism. Methods：Serum of uremic patients and healthy controls were collected and the endothelial cells were treated with serum concentration of 15%. The pas－saged endothelial cells were divided into four groups：normal serum group（N），uremia serum group（U），uremia serum with 10 ?滋mol/L zinc sulfate（U+10），uremia serum with 30 ?滋mol/L Ｚinc sulfate（U+30）. DCFH-DA as fluorescence probe was used to detect reactive oxygen species level by fluorescence microplate reader. Total antioxidant capacity was examined by assay kit with a rapid ABTS method. The expression of NQO-1 and HO-1 mRNA was measured by real-time quantitative RT-PCR. The total protein expression of HO-1，NQO-1 and the Nrf-2 was measured by Ｗestern blot. Results：Compared with those in N group，the total antioxidant capacity of endothelial cells in U group was decreased（P＜0.001） and the ROS was significantly increased（P＜0.001）；while the Ｚinc pretreat－ment（the U+10 and U+30 two group） increased the total antioxidant capacity of cells and decreased the production of reactive oxygen species（all P＜0.001）. Both mRNA and protein expressions of HO-1 and NQO-1 were significantly increased in U and Ｚinc pretreat－ment groups（P＜0.05），more prominent in Ｚinc pretreatment group（P<0.05）. There was no significant difference between U and N groups in terms of the protein expression of Nrf-2，while the Nrf-2 nucleus expression was significantly increased in Ｚinc pretreat－ment group compared with the N and U（P<0.001）. Conclusion：Zinc can improve the total antioxidant capacity and attenuate the ox－idative stress induced by uremia serum in endothelial cells through promoting the Nrf-2 nuclear translocations and increasing the expression of HO-1，NQO-1.