Bone remodeling involves synthesis of organic matrix by osteoblasts and bone resorption by osteoclasts.Recently, anti-diabetic drug metformin has been shown to enhance the proliferation and differentiation of osteoblasts in vitro and prevent bone loss in ovariectomized (OVX) rats.However, the role of mefformin in osteoclast differentiation and the mechanisms through which metformin regulates =osteoclastogensis are not known.