Selective inhibition of collagen synthesis by fluoride in human pulp fibroblasts in vitro

Human dental pulp cells were cultured in fluoridated mediums (0, 1, 10, 25 ppm) in order to study the biological effect of the ion regarding the cellular metabolism: cell growth, alkaline phosphatase (ALP) activity, and protein synthesis. The results indicated a decrease of the cell growth at 25 ppm and a dose-dependent decrease of the ALP activity. Type I collagen immunoperoxidase staining, radioimmunoassay quantitation, and analysis of type I and III collagens mRNA levels showed an inhibition of collagen production and gene expression. In contrast, fibronectin production and gene expression were not affected by fluoride. The treatment did not influence the qualitative pattern of the different mRNA species. Of the three collagen chains, the alpha 1(I) was the most affected. These data suggest that fluoride does not exert a general depletive effect on human dental pulp cells but rather a selective inhibition on collagen production.