ABSTRACT
It is important to identify therapeutic compounds with no adverse effects for use in the chemotherapy of patients with bone-related diseases. The aim of this study was to identify a new compound that inhibits osteoclast differentiation and bone resorption. Herein, we examined the effects of 1',2'-dihydrorotenone on osteoclast differentiation and bone resorption in vitro and in vivo. 1',2'-dihydrorotenone inhibited receptor activator of NF-kappaB ligand (RANKL)-induced osteoclast differentiation of cultured bone marrow macrophages (BMMs) in a dose-dependent manner. However, 1',2'-dihydrorotenone did not exert cytotoxic effect on BMMs. 1',2'-dihydrorotenone suppressed the expression of c-fos and NFATc1 as well as osteoclast-specific genes in BMMs treated with RANKL. Treatment with RANKL inhibited the expression of inhibitors of differentiation/DNA binding (Id)1, 2, and 3; however, in the presence of 1',2'-dihydrorotenone, RANKL did not suppress the expression of Id1, 2, and 3. Furthermore, 1',2'-dihydrorotenone inhibited bone resorption and considerably attenuated the erosion of trabecular bone induced by lipopolysaccharide treatment. Taken together, these results suggest that 1',2'-dihydrorotenone has the potential to be applied in therapies for bone-related diseases.