pH effects on experimental wound healing of human fibroblasts in vitro

The aim of the present study was to examine to what extent pH affects human fibroblast repopulation of an experimental wound in vitro laying special emphasis on cell migration, DNA synthesis, and alterations in cell morphology. Wounds were simulated in vitro by partially scraping off monolayers of human embryonic diploid lung fibroblast and human periodontal ligament fibroblast-like cells respectively. The wounded monolayers were cultured at pHs ranging from 7.2 to 8.4. The experiments were evaluated by autoradiography as well as light and scanning electron microscopic techniques. A significant, approximately linear, decrease was noted both in cell migration into and DNA synthesis in the experimental wounds as a result of pH increase. The surviving cells in the wounds showed cytoplasmatic vacuoles and blebbing at pH levels above 7.8. Clinical implications of these results for endodontic calcium hydroxide treatment are that hydroxyl ions, diffusing through root dentin, may interfere with vital cell functions necessary for healing on the root surface.