EFFECT OF CIPROFLOXACIN ON THE PROLIFERATION OF OSTEOBLAST-LIKE MG-63HUMAN OSTEOSARCOMA CELLS IN-VITRO

Locally applied antibiotic therapy is gaining popularity for the treat ment of infections associated with open fractures and posttraumatic os teomyelitis. With use of local techniques? ciprofloxacin levels as hig h as 1,300 mu g/ml, or over 200 times the bone levels achieved with in travenous administration, have been reported. To study the possible ef fects of ciprofloxacin on bone, osteoblast-like cells from the MG-63 h uman osteosarcoma cell line were studied. The cells were grown in anti biotic-free media and exposed to concentrations of ciprofloxacin at 0, 10, 100, 200, and 1,000 mu g/ml to establish an initial dose-response curve. Media containing the appropriate dose of ciprofloxacin were ch anged every 24 hours. Cell number and [H-3]thymidine incorporation per cell were determined at 0, 24, and 72 hours. A second dose-response c urve was performed at concentrations of 0, 10, 20, 40, and SO mu g/ml. Three experiments, each with four observations, were performed. The r esults of this study demonstrated that ciprofloxacin caused significan t decreases (p < 0.05) in cell number at 40 mu g/ml at 24 hours and 20 mu g/ml at 72 hours. [3H]thymidine incorporation per cell decreased s ignificantly at levels of SO mu g/ml at 24 hours and 20 mu g/ml at 72 hours. The authors conclude that reported local levels of ciprofloxaci n seen in vivo inhibit the proliferation of human osteoblast-like cell s in vitro.