MG63 cells were exposed to various concentrations of alendronate. Cell proliferation and cytotoxicity were evaluated by water-soluble tetrazolium-1 and lactate dehydrogenase, respectively. MG63-mediated collagen degradation was assessed utilising Type I collagen assays. Conditioned media and membrane extracts were collected for Western blot analyses of select MMPs and TIMPs. Gelatin zymography gels were incubated with alendronate to assess its effects on MMP-2 activity.
Alendronate affected MG63 proliferation and cytotoxicity at concentrations equal to/or greater than 10鈭? M (all p < 0.05). There were no significant differences in the collagen degrading ability of treated cells at non-toxic levels vs. untreated cells. Alendronate had no effects on the expression of MMP-2 or MT1-MMP (membrane type-1 MMP) in the conditioned media or membrane extracts, and of MMP-1 or TIMP-2 in the conditioned media. TIMP-2 in the membrane extracts was not detectable. MMP-2 activity in the zymograms was inhibited by 10鈭? and 10鈭? M alendronate.
Alendronate at 10鈭? M or higher was toxic to the cells. Alendronate at 10鈭? to 10鈭? M did not alter the expression of MMP-1, MMP-2, MT1-MMP or TIMP-2, as well as did not alter collagen degradation. Alendronate inhibited MMP-2 activity at 10鈭? and 10鈭? M in the zymograms. In conclusion, non-toxic levels of alendronate (10鈭? to 10鈭? M) did not alter MMP expression in MG63 cells or inhibit MMP-2 activity.