Effect of clindamycin on human osteoblasts treated with zoledronate: An in vitro study

The objective of this study was to determine the effects of combined treatment with clindamycin and zoledronate on the growth and differentiation of cultured human osteoblasts.

Human osteoblasts, obtained by primary culture from mandibular bone fragments, were cultured in the presence of 50 μM zoledronate, 150 μg/mL clindamycin, or the combination of both (zoledronate + clindamycin). The effect on cell proliferation was evaluated at 24 h by the MTT colorimetric method, using a spectrophotometer at 570 nm. The effect on differentiation was examined by measuring alkaline phosphatase (ALP) activity, and mineralization by the osteoblast was studied by staining with alizarin red. Real-time polymerase chain reaction (RT-PCR) was performed for gene expression analysis. Data were expressed as means±standard deviation, and analysis of variance was performed, applying Bonferroni correction when interactions were significant.

Treatment of osteoblasts with 50 μM zoledronate significantly reduced cell proliferation and differentiation and the gene expression of certain markers versus controls (p < 0.001). However, treatment with 150 μg/mL clindamycin significantly increased cell proliferation and differentiation and the gene expression of certain markers (p < 0.05). The combination of 150 μg/mL clindamycin and 50 μM zoledronate partially counteracted the loss of osteoblast proliferative and differentiation capacity caused by zoledronate.

Treatment with low-dose clindamycin can reverse the negative impact of zoledronate on osteoblast proliferation and differentiation. Follow-up animal studies and clinical trials are needed before topical clindamycin can be considered as a possible therapeutic resource for BP-treated patients who require a GBR procedure.