Melatonin At Pharmacological Concentrations Suppresses Osteoclastogenesis Via The Attenuation Of Intracellular ROS

Objective:Osteoporosis is a bone-related disease that is caused by multiple causes of impaired bone formation and / or excessive bone resorption.Melatonin has been clinically recommended for the treatment of osteoporosis because of its ability to promote osteoblastic differentiation.However,the direct effect of melatonin on the production of osteoclasts from bone marrow mononuclear cells(BMMs)remains unknown.The purpose of our study was to see if physiologically or pharmacologically melatonin affects osteoclast differentiation,and the molecular mechanism.Methods:BMMs were isolated from the tibia and femur of C57 BL / 6 mice and induced BMMs to differentiate into multinucleated osteoclasts.Melatonin at physiologic concentrations(0.01 to 10 nM)or pharmacological concentrations(1 to 100 ?M)is then added during the induction of differentiation,and after a period of incubation of the BMMs,tartrate-resistant acid phosphatase(TRAP)staining is used to label the number of TRAP-positive multinucleated osteoclasts and the expression of some osteoclast-specific genes were detected to observe the effect of different concentrations of melatonin on osteoclastogenesis.Exploring the potential mechanism and the role of Silent information regulator type 1(SIRT1)and reactive oxygen species(ROS).Results:Our study found that pharmacological concentrations of melatonin could significantly inhibit osteoclastogenesis and with increasing the concentration of melatoninthe inhibitory effect gradually increased.But the physiological concentration of melatonin could not inhibit osteoclastogenesis.We found a significant reduction in the number of markers of osteoclast-associated specific gene expression in TRAP-positive osteoclasts,which is produced by BMMs at the pharmacological concentrations of melatonin.Melatonin was also found could inhibit osteoclastogenesis by inhibiting the activation of the nuclear factor kappa light chain enhancer B cell(NF-?B)signaling pathway.However,we found that melatonin inhibits osteoclastogenesis was not through the SIRT1 signaling pathway and that the effect of melatonin on osteoclastogenesis can not be affected by SIRT1 inhibitors.However,we review that supplementation of exogenous hydrogen peroxide(H2O2)could partially restore the effect of melatonin on osteoclastogenesis.conclusion:Pharmacological concentrations of MT significantly inhibited the differentiation of BMMs into OC by decreasing intracellular ROS.The effect of MT inhibited osteoclast differentiation was not associated with SIRT1-related signaling pathways.