Figure 2

Inactivation of Notch1 caused beta cell apoptosis.

INS-1 cells were treated with low glucose (5.5 mmol/l glucose, control), or high glucose (11.1, 25, 33.3 mmol/l glucose) for 60 h, followed by PI staining and flow cytometry analysis (A). INS-1 cells were treated with low glucose (5.5 mmol/l glucose, control, white bar), or high glucose (25 mmol/l glucose, black bar) for the indicated times, followed by PI staining and flow cytometry analysis (B). After transient transfection with vector (white bar) or an NICD (black bar) plasmid for 24 h, INS-1 cells were treated with glucose for 24 h when the protein levels of cleaved Notch1 were analyzed (C) and for 72 h the INS-1 cells were stained with propidium iodide (PI) and analyzed by flow cytometry (D). Data shown are means ± SEM and representative of three separate experiments. (A,B) **p < 0.01 vs. control. (D) **p < 0.01 vs. Vector +5.5 mmol/l glucose, and ^##p < 0.01 vs. Vector +25 mmol/l glucose.