[Zoledronate inhibits TRPV5 and NFATc1 expression during differentiation of osteoclasts].

Objective: To explore the effect of zoledronate (ZOL) on osteoclast differentiation and expressions of transient receptor potential vanilloid 5 channel (TRPV5) and nuclear factor of activated T-cells cytoplasmic 1 (NFATc1).

Methods: RAW264.7 cells were divided into two groups for treatment with RANKL for 5 days (group A) or with additional ZOL treatment in the last 2 days of RANKL treatment (group B). Osteoclastogenesis of the cells and the mRNA and protein expressions of TRPV5 and NFATc1 after the treatments were examined.

Results: In group B, the number of newly generated osteoclasts (≥ 3 nuclei), number and size of dentin resorption lacunaes were 29.0 ± 2.4, 24.8 ± 1.1, and 2 030.0 ± 165.7 µm², respectively, which were significantly lower than those in group A (56.5 ± 4.5, 49.3 ± 0.9, and 3 946.7 ± 367.5 µm², respectively, P<0.01). Fluorescent intensity of TRPV5 and NFATc1 were also significantly decreased in group B (P<0.01). Compared with those in group A, TRPV5 mRNA and protein expressions in group B were down-regulated by 50.4% and 37.8%, and those of NFATc1 by 68.0% and 48.4%, respectively (P<0.01).

Conclusion: ZOL can significantly inhibit osteoclastogenesis and bone resorption, which may be attributed, at least partly, to ZOL-induced inhibition of TRPV5 and NFATc1 expressions.