In Vitro Evidence for Effects of Magnesium Supplementation on Quinolone-treated Horse and Dog Chondrocytes
2001
Egerbacher, M. | Wolfesberger, B. | Gabler, C.
Quinolones and magnesium deficiency cause similar lesions in joint cartilage of young animals. Chondrocytes cultivated in the presence of quinolones and in Mg-free medium show severe alterations in cytoskeleton and decreased ability to adhere to the culture dish. We investigated whether Mg²⁺ supplementation can prevent quinolone-mediated effects on chondrocytes in vitro. Chondrocytes cultivated in Dulbecco's modified Eagle's medium/HAM's F-12 medium were treated with ciprofloxacin (80 and 160 μg/ml) and enrofloxacin (100 and 150 μg/ml). Mg²⁺ was added at a concentration of 0.0612 mg/ml (MgCl) and 0.0488 mg/ml (MgSO₄) or a triple dose. In addition, cells were cultivated in Mg-free medium and accordingly treated with Mg²⁺ supplementation. After 5 days in culture, the number of adherent cells per milliliter was determined. The number of chondrocytes in quinolone-treated groups decreased to 12-36% that of the control group within the culture period. With Mg²⁺ supplementation, the number of attached cells increased to 40-70% that of control cells. The threefold dose of Mg²⁺ led to better results than did the single dose. Cell proliferation tested by immunohistochemical staining with Ki67 (clone MIB5) decreased from 70% in control groups to 55%, 48%, and 30% in enrofloxacintreated groups in a concentration dependent manner (50, 100, and 150 μg/ml). Addition of Mg²⁺ did not increase the rate of cell proliferation. These results suggest that a great part of quinolone-induced damage is due to magnesium complex formation, as Mg²⁺ supplementation is able to reduce the effects in vitro. However, quinolone effects on cell proliferation seem to be an independent process that is not influenced by magnesium supplementation.
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