Inhibitory effect of 1,25-dihydroxyvitamin D3 on Porphyromonas gingivalis-induced inflammation and bone resorption in vivo

Abstract

ObjectiveTo investigate whether intragastric administration of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) could inhibit the bone resorption and inflammation in a mouse calvarial model infected by Porphyromonas gingivalis (P. gingivalis). DesignLive P. gingivalis ATCC 33277 was injected once daily for 6days into the subcutaneous tissue overlying the calvaria in mice. At the same time, 1,25(OH)2D3 (50μg/kg per day) was administered by gavage for 9days, starting 3d before the infection. Mice were killed under ether anesthesia 8h after the last injection of P. gingivalis. Micro-computed tomography scanning was used to evaluate calvarial bone loss. Tartrate-resistant acid phosphatase was used to detect osteoclast activity. Real-time PCR was used to assess the mRNA expressions of OPG, RANKL, c-Fos, NFATc1, CTSK and TRAP in calvarial bone and IL-6, IL-10, IL-1β, IL-12p40 and TNF-α in soft tissue. The levels of serum IL-6, IL-10 were determined by ELISA. Results1,25(OH)2D3 treatment apparently attenuated bone resorption in P. gingivalis-induced mouse calvarial model and markedly reduced the number of osteoclasts. The expression levels of RANKL and osteoclast-related genes such as c-Fos, NFATc1, CTSK and TRAP were also decreased by 1,25(OH)2D3. Besides, 1,25(OH)2D3 inhibited the expression of pro-inflammatory cytokines IL-6, IL-12p40 and TNF-α and enormously elevated the expression of anti-inflammatory cytokine IL-10. Conclusion1,25(OH)2D3 may decrease bone resorption in vivo via suppressing the expression of osteoclast-related genes and its anti-inflammatory properties.