Abstract:

Objective  To investigate the types of melanocortin receptor (MCR) of the primary osteoblasts, and the effect of α-melanocyte stimulating hormone (α-MSH) on the expressions of osteoprotegerin (OPG) and receptor activator of nuclear factor-kappa B ligand (RANKL) mRNA in  mouse osteoblasts. Methods  Calvarial osteoblasts were separated and cultured in vitro by the mechanical separation and enzyme digestion method. The primary osteoblasts were divided into groups A, B and C, which were treated with 10-7, 10-8 and 10-9 mol/L α-MSH respectively for 12 h; the primary osteoblasts were divided into groups D, E and F, which were treated with 10-7 mol/L α-MSH for 6, 12 and 24h respectively. Control group was set up at the same time. The expressions of OPG and RANKL mRNA were detected by Real-Time PCR. MCR subtypes in the primary osteoblasts were measured by RT-PCR. Results  MC1R, MC2R, MC4R and MC5R were expressed in primary cultured osteoblasts.The expressions of OPG and RANKL mRNA significantly increased after incubation with α-MSH (P<0.05). Conclusion  α-MSH might promote the expressions of OPG and RANKL mRNA in the primary osteoblasts through MCR system.

Key words: Osteoprotegerin, Recetor activator nuclear factor-kappa B ligand, Melanocortin receptor, α-melanocyte stimulating hormone