Leptin can promote mineralization and up-regulate RANKL mRNA expression in osteoblasts from adult female SD rats.

Osteoblast-related bone formation is an indispensable part of bone remodeling. Osteoblasts can regulate osteoclast activity through the OPG/RANK/RANKL system. Therefore, studies focus on osteoblast proliferation, differentiation, mineralization, and regulation of osteoclasto genes are important. Leptin is a polypeptide encoded by the obesity gene. In the past, regulatory roles of leptin on sugar and lipid metabolism have been extensively studied. In recent years, leptin has been found to have multiple effects on bone metabolism. However, its role in osteoblasts has not been clarified. In order to investigate the effects of leptin on osteoblasts of adult female SD rats, primary cultured osteoblasts were passaged and divided into control and leptin groups. The effects of leptin on osteoblast proliferation, differentiation, mineralization, and OPG and RANKL mRNA expression were observed. Leptin significantly promoted mineralization of osteoblasts in adult female SD rats, and the mineralized area gradually increased with the increase of leptin concentration. When the concentration of leptin was 100 ng/ml, the mineralized area was the highest (P = 0.001). The expression of RANKL mRNA was also elevated by 10 ng/ml leptin. However, leptin had no significant effect on osteoblast proliferation, secretion of ALP, and expression of OPG mRNA in adult female SD rat osteoblast. IJCEP