Abstract
Background: High doses of local antibiotics are used to treat infected acute fractures or chronic osteomyelitis. In the U.S.A., tobramycin is one of the most commonly used antibiotics in trauma surgery. It is an aminoglycoside antibiotic with a broad spectrum of action. However, its effect on the osteogenic potential of bone marrow derived mesenchymal stem cells (MSC’s) is unknown. We hypothesised that high concentrations of tobramycin would be detrimental to the osteogenic potential of multipotent stem cells derived from the bone marrow.
Methods: MSC’s were derived in vitro from reamings obtained in patients undergoing hip hemiarthroplasties. Following subculture, these cells were exposed to various concentrations of tobramycin for 15 days, with a change of media every other day.
The amount of bone formed under each condition was assessed by solubilising the mineral content in hydrochloric acid overnight and then measuring the change in colour induced by Calcium exposed to a commercial reagent. The amount of calcium detected was then determined using a standard curve.
This experiment was repeated in cells from 3 patients.
Results: The amount of calcium formed was as follows Tobramycin concentration of 0 microg/ml
There was a statistically significant impairment in osteogenesis at a concentration of tobramycin of 400 microg/ml and above.
Conclusion: A high local dose of tobramycin affects negatively the osteogenic potential of stem cells derived from the bone marrow.
Correspondence should be addressed to Ms Larissa Welti, Scientific Secretary, EFORT Central Office, Technoparkstrasse 1, CH-8005 Zürich, Switzerland
