Figure 2. The sulfate group is required for biological effects of chondroitin sulfate. Palatal fibroblasts were cultured for 8 hrs in normal culture medium, medium supplemented with 30 mmol/L chlorate, or medium with 30 mmol/L chlorate plus (A) 10 mmol/L sulfate or (B) 100 ng/mL chondroitin-6-sulfate (C6S). The number of adherent cells varied among treatment groups (one-way ANOVA; p < 0.0001), with fewer adherent cells in the chlorate-alone-treated group compared with the control group (Tukey’s test; p < 0.001 in both panels). Fibroblasts treated with chlorate plus exogenous sulfate or chondroitin-6-sulfate showed significantly greater adhesion than those treated with chlorate alone (p < 0.001 in each case). (C) In the cell proliferation assay, continuous chlorate treatment also led to reduced cell numbers after a seven-day culture period (p < 0.001). This reduction was significantly blocked by the addition of 100 ng/mL chondroitin-6-sulfate to the culture medium (p < 0.001). Values represent mean ± SEM of 3 experiments.