Ellagic Acid Protects Ovariectomy Induced Bone Loss In Mice By Inhibiting Osteoclast Differentiation And Bone Resorption

Research background and purpose: As society gradually enters the aging stage,age-related diseases are increasingly becoming a burden on society.Among them,osteoporosis is one of the diseases that mainly endanger human health.In recent years,the incidence of osteoporosis has been increasing year by year.Osteoporosis is a systemic bone disease characterized by a reduction in bone mass,destruction of bone tissue microstructure,resulting in decreased bone strength,increased bone fragility and fracture.Osteoporotic fractures are more harmful,which can lead to the majority of patients unable to take care of themselves,the quality of life is significantly reduced,and even die from various serious complications.The existing osteoporosis treatments present certain side effects,which limits their clinical application,and the treatment of osteoporosis with high efficiency and low side effects has become an urgent problem to be solved.The balance of bone metabolism is mainly the balance between the bone resorption of osteoclasts and the bone formation of osteoblasts,and osteoporosis is mainly caused by this balance being broken,and often due to the formation of osteoclasts.The number of osteoclasts is increased,or the bone resorptionfunction is enhanced,so finding a drug that can effectively inhibit osteoclast formation or bone resorption function becomes a method for treating osteoporosis.In this topic,our previous experiments found that the plant extract ellagic acid can inhibit the differentiation of osteoclasts,and further explore the prevention and treatment of ellagic acid on osteoporosis.Ellagic acid is a natural phenolic antioxidant present in fruits,including plants such as blackberries and raspberries.Previous studies have confirmed that ellagic acid has many effects such as anti-proliferation and anti-oxidation,anti-tumor,anti-inflammatory and anti-ultraviolet effects.However,the role and molecular mechanism of ellagic acid in bone metabolism is still unclear.This study will explore the formation and bone-resorption function of ellagic acid and its molecular mechanism,and further explore the model of osteoporosis caused by ovariectomized mice,and explore the effect of ellagic acid on osteoporosis,and provide new ideas for the treatment of osteoporosis and osteolytic diseases.Experimental method: in vitro experiment: by extracting bone marrow macrophages(BMMs)from mouse tibia,the effect of ellagic acid on the proliferation of BMMs was determined by cck8 kit.The effect of ellagic acid on osteoclast differentiation was further explored by TRAP staining,the osteoclast-like cells were seeded on the hydroxyapatite plate to investigate the effect of ellagic acid on the bone resorption function of osteoclasts,and the effect of ellagic acid on the marker genes of osteoclast was further quantitatively analyzed by RT-PCR.Finally,western blot was used to explore the effect of ellagic acid on the molecular mechanism of osteoclasts.In vivo experiment:mouse ovariectomized(OVX)osteoporosis model: 12-week-old male C57 mice were randomly divided into 4 groups,sham operation group,OVX + ellagic acid high-dose group,OVX + ellagic acid low-dose group,mouse samples werecollected after 7 weeks.Micro-CT scan and tissue analysis were performed on mouse bone mass changes.H&E staining and CTSK staining were used to observe the histological morphology of the mice.Results: In this study,we began to discover that the plant extract ellagic acid inhibits the expression of NF-?B transcription factors by the fluorescent protein reporter gene,which is an important signaling pathway in osteoclast.In further studies,we found that ellagic acid inhibited osteoclast differentiation and bone resorption in vitro and inhibited the expression of osteoclast marker genes.We found that ellagic acid inhibited osteoclast differentiation by inhibiting NF-?B and NFAT signaling pathways.In in vivo experiments,we found that ellagic acid has a significant preventive effect in the osteoporosis model caused by ovariectomy in mice.Taken together,these results indicate that ellagic acid can effectively prevent and treat osteoporosis by inhibiting the formation of osteoclasts and bone resorption.Therefore,ellagic acid may be a potential drug for the treatment of osteoporosis and may be able to treat other osteolytic diseases associated with osteoclasts.The research results of this subject can provide a theoretical basis for the clinical development of new drugs.Conclusion: Ellagic acid can protect osteoporosis caused by ovariectomy in mice by inhibiting osteoclast differentiation and bone resorption.