Abstract:

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.