Bisphosphonate effects on capthesin K and bone resorption function during osteoclast differentiation

Dong Wei; Feng Xiao-jie; Liang Yong-qiang; Peng Hong-feng; Deng Jiu-peng; Wen Li-ming; Qi Meng-chun

doi:10.3969/j.issn.2095-4344.2014.33.008

Abstract：BACKGROUND:Studies have shown that bisphosphonates inhibit osteoclast resorption, but whether cathepsin K, a key cytokine of bone resorption, plays an effect has rarely been reported. <br> OBJECTIVE:To study the effect of bisphosphonate on capthesin K and bone resorption function during osteoclast differentiation. <br> METHODS:Osteoclasts were cultured by mouse monocyte-macrophage cellline-RAW264.7. The cells were divided into two groups:control group, treated with 100μg/L receptor activator of nuclear factorκB ligand factor;alendronate group, treated with 100μg/L receptor activator of nuclear factorκB ligand factor+10-7 mol/L alendronate. Osteoclastogenesis and resorption function of osteoclasts were examined at 7 days of culture and gene expression of capthesin K was detected by immunofluorescence method at 72 hours of culture. Western blot assay was used to detect capthesin K protein expression at 72 hours of culture. <br> RESULTS AND CONCLUSION:Tartrate-resistant acid phosphatase positive multinuclear cells were observed and resorption lacunae formed in two groups. Control group showed the higher number of tartrate-resistant acid phosphatase positive multinuclear cells and larger size of resorption lacunae than the alendronate group (P<0.01). Immunofluorescence showed expression of capthesin K was higher in the control group than the alendronate group (P<0.01);furthermore, the protein expression of capthesin K was also lower in the alendronate group than the control group (P<0.01). These findings indicate that bisphosphonates could strongly inhibit osteoclastogenesis and its resorption function by inhibiting gene expression of capthesin K.