Bone toxicity of locally applied aminoglycosides.
The effect of tobramycin on osteoblasts was studied. Osteoblast-like cells from the MG-63 human osteosarcoma cell line were grown in antibiotic-free media and exposed to concentrations of tobramycin: first at order of magnitude intervals between 0 and 10,000 micrograms/ml, and then at closer intervals between 100 and 1,000 micrograms/ml to more accurately define toxic levels. Cell number and 3H-thymidine incorporation at 0, 24 and 72 h were determined. Similarly, primary cultures of rat osteoblasts were exposed to the same concentrations of tobramycin to confirm the validity of the MG-63 cell line as a model for nontransformed cells. The results of this study demonstrate that local levels of tobramycin of < or = 200 micrograms/ml have little or no effect on osteoblast replication. Concentrations of 400 micrograms/ml significantly decreased cell replication, and concentrations of 10,000 micrograms/ml caused cell death. Results obtained with primary rat osteoblast cultures were similar to those obtained from the MG-63 cultures at the tested tobramycin concentrations.
Miclau
T
T
University of California at San Francisco, Department of Orthopaedic Surgery, San Francisco General Hospital 94110, USA.
Edin
M L
ML
Lester
G E
GE
Lindsey
R W
RW
Dahners
L E
LE
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002452:Cell Count; D016923:Cell Death; D004305:Dose-Response Relationship, Drug; D006801:Humans; D010006:Osteoblasts / Q000187:drug effects*; D012516:Osteosarcoma; D051381:Rats; D014031:Tobramycin / Q000008:administration & dosage / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
D000900:Anti-Bacterial Agents; D014031:Tobramycin