Effect of oxidative stress on apoptosis of MC3T3-E1 osteoblasts induced by glucose fluctuation / 中华内分泌代谢杂志

ABSTRACT

Objective To investigate the effects of high glucose and glucose fluctuation on the apoptosis of MC3T3-E1 osteoblasts. Methods MC3T3-E1 osteoblasts cultured in vitro were divided into control, N-acetyl-L-cysteine ( NAC) group, high glucose ( HG), HG + NAC, glucose fluctuation ( GF), and GF + NAC groups. Cell proliferation was examined by CCK-8 analysis. The apoptosis rates of cells in different groups were measured by flow cytometry, which was stained with Annexin V-FITC/ PI. The protein expressions of Bax and Bcl-2 were detected by Western blot. DCFH-DA probe was used to measure reactive oxygen species (ROS) level. Results Compared with control group, the proliferation rates of cells in HG and GF groups were significantly declined(P<0. 01), especially more obviously in GF group(P<0. 05). The apoptosis rates in HG and GF groups were higher than that in control group(P<0. 05 or P<0. 01), being higher in GF group than in HG group(P<0. 01). The protein expressions of Bcl-2 were decreased in HG and GF groups compared with control group (P<0. 01) while Bax expression was raised (P<0. 05 or P<0. 01). Compared with HG group, Bcl-2 expression was lower and Bax expression was higher in GF group (P<0. 05). HG and GF promoted the production of ROS, especially the latter. NAC suppressed the production of ROS, increased Bcl-2 expression, while decreased Bax expression, and ameliorated the elevated cell apoptosis rate. Conclusion Glucose fluctuation aggravates high glucose-induced oxidative stress, which contributes to the declined proliferation and increased apoptosis of MC3T3-E1 osteoblasts.