Effects of psoralen on the expressions of receptor activator of nuclear factor-κB ligand and osteoprotegerin in murine osteoblasts in vitro

Objective To investigate the role of psoralen on the differentiation of murine osteoblasts(OB),and to observe the expressions of receptor activator of nuclear factor-κB ligand(RANKL) and osteoprotegerin(OPG)in vitro.Methods The calvarial OB of newborn BALB /c mice were cultured in MEM medium containing 10 % NCS.Psoralen was supplemented into the culture medium of osteoblast at 0.1,1 and 10 μmol/L respectively.MTT was used to observe the proliferation and the growth curve was obtained.The osteoblasts alkaline phosphatase(ALP) activity assays were performed by PNPP method,and mRNA expressions of OPG and RANKL were determined by RT-PCR.Results The growth curve showed that the OB quantities of each group had increased accompanied with time.Higher and middle concentration of psoralen significantly increased the ALP activity in OB in vitro,up-regulated the mRNA expressions of RANKL and OPG,increased the ratio of OPG/ RANKL.Conclusions Lower dosage of psoralen(0.1 μmol/L)has no significant effect on bone turnover,but higher and middle dosage of psoralen(1,10 μmol/L) can enhance bone turnover through facilitating the formation and activity of OB via up-regulating the expressions of RANKL and OPG and increasing the ratio of OPG/RANKL.