Fig. 2

Metformin enhanced the osteogenic differentiation of PDLSCs under high glucose. A ALP staining and ALP activity assay of PDLSCs when they were cultured in normal (CON), high glucose (HG) or high glucose with metformin addition (HG + MET) following a 7-day osteogenic induction (scale bar = 200 µm). B Alizarin Red staining and quantitative analysis of the stained calcium deposits formed by PDLSCs when they were cultured in normal (CON), high glucose (HG) or high glucose with metformin addition (HG + MET) following a 21-day osteogenic induction (scale bar = 200 µm). C Expression of osteoblast differentiation-related genes (ALP, RUNX2, BMP2 and OCN) in PDLSCs when they were cultured in normal, high glucose or high glucose with metformin addition following a 14-day osteogenic induction (mRNA expression levels detected by qRT-PCR). D Expression of osteoblast differentiation-related proteins (ALP, RUNX2, BMP2 and OCN) in PDLSCs when they were cultured in normal, high glucose or high glucose with metformin addition following a 14-day osteogenic induction (protein expression levels detected by Western blot analysis). The displayed bands were cropped from the corresponding original blots. HG, high glucose. Met, metformin. Experiments for P4 cells from three different donors were repeated independently for at least 3 times, and data are presented as the means ± SD (n = 3). p value was based on one-way analysis of variance (one-way ANOVA). *p < 0.05, **p < 0.01, and ***p < 0.001 represent significant differences between the indicated columns, while NS represents no significant difference