EFFECTS OF 1α,25(OH)_2D_3 ON THE EXPRESSION OF RECEPTOR ACTIVATOR OF NF-КB LIGAND AND OSTEOPROTEGERIN IN RAT OSTEOBLASTS IN VITRO

Objective To investigate the effect of 1α,25-dihy-droxyvitamin D3 (1α,25(OH)2D3) on the expression of receptor activator of NF-КB ligand (RANKL),osteoprotegerin (OPG) and RANKL mRNA,OPG mRNA,of rat osteobalsts (OB). Method The expression of RANKL and OPG was detected by the method of Immunohistochemistry and ELISA. RANKL mRNA and OPG mRNA were determined through FQ-PCR. Results Compared with the control group and the group with 1 nmol/L 1α,25(OH)2D3,10 and 100 nmol/L 1α,25(OH)2D3 can significantly induce the expression of RANKL and RANKL mRNA. 1,10 nmol/L 1α,25(OH)2D3 can stimulate the expression of OPG and OPG mRNA significantly,while 100 nmol/L 1α,25(OH)2D3 can inhibit the expression of OPG mRNA significantly. There were no difference in the rate of RANKL/OPG and RANKL mRNA/OPG mRNA between the control group and the group with 1 nmol/L 1α,25(OH)2D3,however the rate of RANKL/OPG and RANKL mRNA/OPG mRNA in the group with 10,100 nmol/L were higher than the control group and the group with 1 nmol/L 1α,25(OH)2D3. Conclusion Lower dosage of 1α,25(OH)2D3 (1 nmol/L) had no significant effect on bone turnover,but higher dosage of 1α,25(OH)2D3 (10,100 nmol/L) can enhance bone turnover through facilitating the formation and activity of osteoclasts via enhancing RANKL mRNA/OPG mRNA and RANKL/OPG..