Inflammation reduces osteoblast cytotoxicity induced by diclofenac: An in vitro study

BACKGROUND Diclofenac and other NSAIDs are routinely used in the postoperative period. Their effect on fracture healing remains unclear and controversial. OBJECTIVE The primary outcome was to assess the potential cytotoxicity of clinically relevant concentrations of diclofenac on human osteoblasts. DESIGN Laboratory in vitro study. SETTING Institute of Physiology, Zurich, Center for Integrative Human Physiology, University of Zurich. MATERIALS Monolayers of human osteoblasts. INTERVENTIONS Exposure of human osteoblast monolayers to several concentrations of diclofenac, for different periods of time, with and without an artificially induced inflammatory process. MAIN OUTCOME MEASURES Cell count, cell viability, cell proliferation and apoptosis. RESULTS A concentration-mediated, time and exposure dependent cytotoxic effect of diclofenac-mediated apoptosis was observed. Stimulated inflammatory conditions seemed to reduce toxic effects. CONCLUSION Cytotoxic effects of diclofenac are exposure, time and concentration dependent. Simulating aspects of inflammatory conditions seems to increase resistance to diclofenac cytotoxicity, especially in the presence of higher concentration and longer exposure time