Figure 1.

Potassium gluconate inhibits fibroblast proliferation. (A-D) Representative images of fibroblasts cultured in (A) 0, (B) 40, (C) 60, and (D) 80 mM of exogenous potassium gluconate for 3 days. Arrowheads indicate representative Ki67 positive cells. Scale: 100 μm. (E) Quantification of the percentage of Ki67 positive fibroblasts. (F) Quantification of the density of fibroblasts cultured for 3 days in increasing concentrations of potassium gluconate. (G) Quantification of the metabolic activity of fibroblasts grown for 3 days in increasing concentrations of potassium gluconate. Data were normalized to the metabolic activity of control fibroblasts (black bar). (H) Quantification of the metabolic activity of fibroblasts cultured for 3 days with (constant) or without (late) potassium gluconate. After 3 days, fibroblasts were switched to differentiation medium with potassium gluconate. As controls, fibroblasts were not cultured in potassium gluconate either without differentiation medium (white bar, negative control), or with differentiation medium (green bar, positive control). Data were normalized to the metabolic activity of the negative control. * (p<0.05), ** (p<0.01), *** (p<0.001) and brackets indicate significance from other surfaces as determined by one-way ANOVA with Holm-Sidak post hoc analysis (n=5 independent experiments).