Effects of citric acid on cultured human osteoblastic cells

We investigated the effects of citric acid (CA) on cultured human osteoblastic (HOB) cells by evaluating cell adhesion, proliferation, and cytotoxicity. H-3-Thymidine-labeled HOB cells were incubated in culture medium supplemented or not with 4%, 6%, 8%, or 10% CA for 1 minute. After incubation, cell morphology was evaluated by Nomarski interferential light microscopy, cell proliferation was accessed by measurements of H-3-thymidine associated to the cells, and cell lysis was monitored by measuring the amount of H-3-thymidine released by cells. We observed that most of the CA-treated cells presented numerous atypical vacuoles, and such cells were also highly polymorphic, exhibiting round-shaped cells. Nonetheless, CA at all concentrations assayed did not yield cytotoxicity as measured by H-3-containing DNA release, although significant decrease in cell proliferation was observed (P > .05). Furthermore, cells which were treated with CA at the lowest concentration assayed (4%) restored normal proliferation rates 3 days after treatment. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010; 110: 665-669)