Metformin induced mainly apoptosis in NG and both apoptosis and necrosis in HG. (A) The percentage of early apoptotic, late apoptotic and necrotic cells detected at 24, 48, and 72 h of the culture of SKOV-3 cells in NG and HG in the presence and absence of 10 mM metformin. Results are presented as means ± S.D. of four experiments. NG—cells cultured in normoglycemia, NG + M—cells cultured in normoglycemia and treated with metformin, HG—cells cultured in hyperglycemia, HG + M—cells cultured in hyperglycemia and treated with metformin. (*) Statistically significant differences between the cells exposed to metformin in comparison to unexposed cells at the same time points, p < 0.05; (+) statistically significant differences between metformin treated cells in different time points, p < 0.05. (B) The morphological changes of SKOV-3 cells, which were cultured in NG and HG with and without exposure to 10 mM metformin for 48 h and stained with Hoechst 33258 and PI, visualized by fluorescence microscopy (Olympus IX70, Japan; bar 200 µm).