Effect Of Betulinic Acid On Osteoclasts And The Molecular Mechanisms

Research background and purpose: Bone homeostasis between maintenance and osteoclasts,and osteoblasts function coordination,osteoclasts with absorption of bone tissue and bone mass,bone remodeling adjustment function,and the bone formation and bone matrix mineralization mainly by osteoblasts adjustment,when excessive activation of osteoclasts or enhancements will cause the bone absorption increase,bone destruction that cause osteoporosis,osteoarthritis,rheumatoid arthritis,bone disease,drugs currently used in the treatment of these diseases while has developed a lot of kinds,but the long-term use of adverse reaction is bigger,easy to cause damage to the body,Therefore,it is urgent to develop anti-bone loss drugs with definite efficacy and fewer adverse reactions.In recent years,with the recognition of Chinese traditional medicine in the world,Chinese traditional medicine and natural products have come into people’s field of vision and become the focus of anti-bone loss drug treatment.Betulinic acid(BA)is derived from a variety of plants such as birch bark and papyrus leaf,and belongs to pentacyclic triterpenoids.Previous studies at home and abroad have shown that BA has a variety of biological activities such as anti-tumor,antiviral,anti-inflammatory and immune regulation.But birch fatty acid in the role of bone metabolism and its molecular mechanism is unclear,the study will investigate birch fatty acid of osteoclast differentiation and bone resorption function,dig into the internal mechanism of its function,further to ovarian caused by osteoporosis by constructing mice model,to explore the birch fatty acid on mouse model of osteoporosis bone loss of protection.Therefore,this study will expound the molecular mechanism of BA regulating osteoclast differentiation and function from the above aspects,providing a new theoretical basis for the drug treatment of osteoporosis and other bone loss diseases.Experimental method: In vitro experiment: bone marrow macrophages(BMMs)were extracted from the tibia of mice,and the effect of BA on the proliferation of BMMs was determined by cck8 kit,and the effect of BA on osteoclast differentiation was further explored by TRAP staining.Then,osteoclastic cells were planted on hydroxyapatite plate to explore the effect of BA on osteoclast bone resorption function.The ROS kit was used to detect the effect of BA on the generation level of intracellular reactive oxygen species.Furthermore,RT-PCR was used to quantitatively analyze the effect of BA on the marker genes of osteoclast maturation.Finally,western blot was used to investigate the effect of BA on the molecular mechanism of osteoclasts.In vivo experiment: bilateral ovaries removed mice(OVX)osteoporosis model was constructed,10 weeks of large female C57 mice were randomly divided into blank control group,control group,the OVX + BA low-dose group,the OVX +BA high dose group,a total of four groups,each group of eight,after 4 weeks of BA or PBS collect tibia in mice after processing,Micro-CT scans and organization analysis of mice bone mass changes,HE staining and TRAP staining to observe histological morphology in mice.Results: In vitro experiments,we found that BA can inhibit osteoclast differentiation and bone resorption,inhibit the formation of actin rings in osteoclasts and the generation of intracellular reactive oxygen species,and inhibit the expression of osteoclast related genes.Its inhibition of osteoclast differentiation and function is mediated by the inhibition of MAPK and NFATc1 signaling pathways.In vivo,we found that BA had a significant protective effect in osteoporosis model mice with bilateral ovaries removed.Taken together,these results suggest that BA may have therapeutic effects on osteoporosis in vivo and in vitro by inhibiting osteoclast formation and bone resorption.Therefore,BA may be a potential drug for the treatment of osteoporosis and other bone loss diseases.The research results of this subject can provide a new theoretical basis for the clinical transformation of drugs and the development of new drugs.Conclusion: BA protected bone loss in mice with bilateral ovaries by inhibiting osteoclast differentiation and bone resorption.