间歇性高糖对胰岛β细胞生长及细胞周期进程的影响

背景：间歇性高糖可阻滞胰岛β细胞生长，增加β细胞的凋亡，但具体作用机制尚不清。 目的：观察间歇性高糖对大鼠胰岛素细胞增殖、凋亡及对细胞周期进程的影响。 方法：实验对大鼠胰岛素细胞进行培养，分为正常糖对照组，恒定性高糖组和间歇性高糖组，分别含葡萄糖5.5，30，30和5.5 mmol/L间歇换液。采用细胞计数试剂盒检测细胞增殖活性，流式细胞仪测定细胞周期，Annexin-V/PI双标流式细胞术检测细胞凋亡，应用Western blot检测细胞周期调控蛋白Cyclin D1的表达水平。 结果与结论：与正常糖对照组相比，恒定性高糖组及间歇性高糖组均明显抑制大鼠胰岛素细胞细胞的生长(P < 0.01)，增加大鼠胰岛素细胞的凋亡(P < 0.01)，明显抑制细胞周期进程，使大鼠胰岛素细胞的细胞周期更多滞留在G0/G1期(P < 0.01)，能显著减弱细胞周期调控蛋白Cyclin D1的表达(P  < 0.01)。与恒定性高糖组相比，间歇性高糖以上各指标作用均更显著(P  < 0.01)。结果证实，间歇性高糖能够抑制大鼠胰岛素细胞的生长，增殖和诱导凋亡，其机制可能是通过降低Cyclin D1的活性，使细胞阻滞在G0/G1期，抑制细胞周期进程，从而减弱细胞的增殖活性。

Effect of intermittent high glucose on growth and cycle progression of islet beta cells

BACKGROUND:Intermittent high glucose can block the growth of islet β cells and increase the apoptosis rate of β-cell, but the specific mechanism is not fully understood. OBJECTIVE:To investigate the effect of intermittent high glucose on proliferation, apoptosis and cell cycle progression of rat insulin-secreting (INS-1) cells. METHODS:INS-1 cells were cultured and randomly divided into the control, intermittent and constant high glucose groups, which was treated by 5.5, 30, 30 and 5.5 mmol/L glucose intermittently. Cell viability was evaluated by cell counting kit and the cell cycle was determined by flow cytometry. Annexin-V/PI double-labeled cell apoptosis detection kit was used to monitor cell apoptosis. Cell cycle related protein Cyclin D1 expression was detected by Western blot. RESULTS AND CONCLUSION:Both intermittent and constant high glucose significantly inhibited the growth of INS-1 cells, compared with the normal glucose (P  < 0.01), increased apoptosis in INS-1 cells (P < 0.01), inhibited the cell process, arrested G0/G1 cell cycle (P  < 0.01), as well as decreased the level of cell cycle related protein Cyclin D1 (P < 0.01). Compared with the constant high glucose group, all the effects of intermittent high glucose were more notably (P < 0.01). Intermittent high glucose affect INS-1 cell growth and proliferation, it also induce cell apoptosis, probably by decreasing the level of Cyclin D1 in the cells, which result in arresting in progression through the G1 phase to the S phase, and thus impair cell proliferation.