Effects of high glucose fluctuation on expressions of TRAIL and OPG in MG63 cells

Objective To observe the regulative effects of glucose at different concentrations on the expressions of tumor necrosis factor-related apoptosis,which inducing ligand(TRAIL),osteoprotegerin(OPG),and the ligand of osteoprotegerin(OPGL) in osteosarcoma MG63 cells in order to study the role of high glucose fluctuation in pathogenesis of diabetic osteoporosis.Methods MG63 cells were randomly divided into the following medium containing 5.5 mmol/L glucose(Normal glucose group,NG group),33.3 mmol/L glucose(High glucose group,HG group) and 5.5/33.3 mmol/L glucose(high glucose fluctuation of different amplitude 5.5/33.3 mmol/L group,FG group) and cultured in vitro for 24 h.The proliferation of MG63 cells was examined by MTT colorimetric analysis.The cell cycle and apoptotic rate of cells were determined by flow cytometry.The expressions of TRAIL,OPG and OPGL mRNA were detected by RT-PCR.Results Both high glucose and high glucose fluctuation inhibited the proliferation of MG63 cells,and the effect of high glucose fluctuation was significantly higher than that in high glucose(P0.05).Both high glucose and high glucose fluctuation blocked cell cycle,increased the percentage of G1 phase,decreased the percentage of S phase and induced apoptosis.The effect of high glucose fluctuation was obviously stronger than that in high glucose(P0.05).The mRNA expressions of TRAIL and OPGL in MG63 cells significantly increased and the expression of OPG mRNA decreased under high glucose environment(P0.05).The mentioned effects were obviously power in FG group than that in HG group.Conclusion High glucose fluctuation could not only inhibit the proliferation,block cell cycle,induce apoptosis,and also lead to the increasing expressions of TRAIL and OPGL,but the decreasing expression of OPG in osteoblasts,which may be one of the key pathogenetic factors of diabetic osteoporosis.