Protective effect and its mechanism of osteoprotegerin on human umbilical vein endothelial cells cultured with high glucose / 中华内分泌代谢杂志

ABSTRACT

Objective To explore the effect and its mechism of osteoprotegerin (OPG) on human umbilical vein endothelial cells(HUVECs) induced by high glucose.Methods (1) The cultured HUVECs were treated with normal glucose(5.5 mmol/L),high glucose(33 mmol/L),high glucose + OPG(0.5,1,and 2 μg/ml)as well as mannitol(5.5 mmol/L glucose+27.5 mmol/L mannitol) for 48 h,respectively.Flow cytometry assay and Hoechst 33258 staining were used to detect the cell apoptosis.The expression levels of Bcl-2 and Bax protein were measured by western blot analysis.(2) The cultured HUVECs were treated with normal glucose,high glucose,high glucose + OPG (2 μg/ml OPG),high glucose + rapamycin(10 ng/ml rapamycin) as well as high glucose + rapamycin + OPG for 24h,respectively.The expression levels of S6K,p-S6K,4EBP1 and p-4EBP1 protein were measured by western blot analysis.(3)The cultured HUVECs were treated with normal glucose,high glucose,high glucose + OPG(2 μg/ml)for 24 h,respectively.The expression levels of tuberin and p-tuberin protein were measured by western blot analysis.Results (1) Compared with normal glucose group,the apoptosis of HUVECs and the expression level of Bax was dramatically increased,and the expression of Bcl-2 was decreased significantly in high glucose group (P＜0.05).The apoptosis of HUVECs and the expression level of Bax in high glucose + OPG group was significantly lower than that in high glucose group,which was still higher than that in normal glucose group (P＜ 0.05).and the expression of Bcl-2 in high glucose + OPG group was significantly higher than that in high glucose group,which was still lower than that in normal glucose group (P＜0.05).There was no statistically difference between hyperosmolar control group and normal glucose group.(2) Compared with normal glucose group,the expression levels of p-S6K and p-4EBP1 were increased markedly in high glucose group(P＜0.05).The expression levels of p-S6K and p-4EBP1 in high glucose + OPG group were significantly lower than that in high glucose group,which were still higher than that in normal glucose group(P＜0.05).No significant difference was found between high glucose + OPG group and high glucose + rapamycin group.(3) Compared with normal glucose group,the expression level of p-tuberin was increased markedly in high glucose group (P ＜ 0.05).The expression level of p-tuberin in high glucose + OPG group was significantly lower than that in high glucose group,which was still higher than that in normal glucose group (P ＜0.05).Conclusions It suggests that the protective effect and mechanism of OPG on HUVECs cultured with high glucose may be association with tuberin/mTORC1 pathway.