新型低频动态交变磁疗对维甲酸诱导骨质疏松大鼠骨代谢及骨微结构的影响OA

BACKGROUND:The application of low-frequency magnetotherapy in the field of osteoporosis has gradually attracted attention.Some animal experiments and preliminary clinical studies have shown that low-frequency magnetotherapy may help improve bone mineral density and bone microstructure.However,there is still a lack of clinical evidence and standardized protocols regarding the optimal parameters,long-term efficacy,and safety evaluation of magnetotherapy in the treatment of osteoporosis,and its specific mechanism of action has not yet been fully elucidated. OBJECTIVE:To investigate the effects of a novel low-frequency alternating dynamic magnetotherapy device on bone microstructure and bone metabolism in a retinoic acid-induced osteoporotic rat model. METHODS:Forty Sprague-Dawley rats,weighing body mass 200-250 g,were randomly divided into normal control group,model group,magnetotherapy treatment group,and positive control group,with 10 rats in each group.The normal control group received intragastric administration of normal saline.The other three groups received 100 mg/kg retinoic acid by continuous intragastric administration for 14 days to establish osteoporosis models.After successful modeling,the magnetotherapy treatment group received low-frequency magnetotherapy intervention,30 minutes per day,6 times per week,for 4 weeks.The positive control group received intragastric administration of alendronate sodium at 2 mg/(kg·d),3 times per week,for 4 weeks.After intervention,serum and femoral samples were collected.Micro-CT was used to analyze bone microstructure parameters(bone volume fraction,trabecular thickness,and trabecular spacing).Serum levels of osteocalcin,bone alkaline phosphatase,and C-terminal telopeptide of type Ⅰ collagen were detected by ELISA.Hematoxylin-eosin staining and tartrate-resistant acid phosphatase staining were used to observe bone tissue morphological changes and osteoclast activity. RESULTS AND CONCLUSION:(1)Compared with those in the normal control group,rats in the model group showed obvious osteoporotic manifestations,including decreased bone mineral density,thinning and fracture of bone trabeculae,and enhanced osteoclast activity.(2)The magnetotherapy treatment group showed that low-frequency alternating dynamic magnetotherapy intervention could significantly increase bone mineral density,improve bone microstructure parameters(increased bone volume fraction,increased trabecular thickness,and decreased trabecular spacing),promote osteoblast activity(increased osteocalcin and bone alkaline phosphatase levels),and inhibit osteoclast-mediated bone resorption(decreased C-terminal telopeptide of type Ⅰ collagen level and reduced tartrate-resistant acid phosphatase-positive cells)in osteoporotic rats.Overall,these findings suggest that low-frequency alternating dynamic magnetotherapy can effectively ameliorate retinoic acid-induced osteoporosis by promoting osteoblast proliferation and differentiation and inhibiting osteoclast activity,thereby exerting a bidirectional regulatory effect on bone metabolism,providing new insights and experimental evidence for non-pharmacological treatment of osteoporosis.