Effect of interleukin-10 on gene expression of osteoclastogenic regulatory molecules in the rat dental follicle.

The aim of this study was to determine the effect of interleukin-10 (IL-10) on the gene expression of osteoclastogenic regulatory molecules in rat dental follicle cells. Interleukin-10 is an anti-inflammatory cytokine that inhibits alveolar bone resorption, but the molecular basis for this is unknown. Alveolar bone resorption is required for tooth eruption and the dental follicle functions to regulate the osteoclastogenesis needed for eruption. It does this by regulating its expression of receptor activator of nuclear factor-kappa B ligand (RANKL), colony-stimulating factor-1 (CSF-1), and osteoprotegerin (OPG). In this study, dental follicle cells were treated with IL-10, and the effect on gene expression of CSF-1, RANKL, and OPG was measured by reverse transcription-polymerase chain reaction (RT-PCR). Interleukin-10 enhanced the expression of OPG and down-regulated the expression of RANKL and CSF-1. Laser capture microdissection was carried out to detect IL-10 gene expression in the dental follicle. Knockdown of the IL-10 gene expression in the follicle cells was accomplished using a short interfering RNA (siRNA) targeting IL-10 mRNA. In these knockdowns, RANKL expression was increased and OPG expression was decreased. All of these results suggest that IL-10 inhibits bone resorption by up-regulating OPG expression while down-regulating expression of RANKL and CSF-1.