Cordymin alleviates osteoporosis induced by hindlimb unloading via regulating the gut - microelements -bone axis --for non-clinical studies

INTRODUCTION: The purpose of this study was to evaluate the protective effects of cordymin on osteoporosis induced by hindlimb unloading(HLU) in rats and whether cordymin can prevent bone loss from HLU. MATERIALS AND METHODS: We employed the hindlimb suspension rats model to mimic physiological changes concomitant with space travel.The mechanical strength in the femoral neck,cancellous bone volume, gut microbiota structure,serum calcium and phosphorus contents, bone mineral content and bone mineral content can be changed after hindlimb unloading. Oral cordymin was administered for 4 weeks,cordymin treatment significantly increased the mechanical strength through elevated bone volume/tissue volume (BV/TV), trabecular number (Tb. N), trabecular thickness (Tb. Th) and decreased trabecular separation (Tb. Sp). RESULTS: Importantly, 16 S rRNA sequencing showed cordymin treatment regulated the various genera that were imbalanced in hindlimb unloading rats. At the same time,The plasma total calcium and inorganic phosphate concentrations in hindlimb unloading rats decreased and bone mineral content in the lumbar vertebrae and femur increased after treatment with cordymin. CONCLUSION: These data indicate that the cordymin might exert bone protective effects indirectly via modulating the complex relationship between gut microbiota, microelements and bone loss.