The Effect of Prior Exercise on Bone Morphological Microstructure after Immobilization in Mice

PURPOSE The purpose of this study was to analyze the differences of bone density and structure after immobilization prior aerobic exercise and resistance exercise. METHODS Twenty four mice were randomly divided into 3 groups: CC: 4weeks control cage after 2 weeks immobolization (n=7), RT: 4 weeks resistance training after 2 weeks immobilization (n=7), AE: 4 weeks aerobic training after 2 weeks immobilization (n=7). The prior exercise was performed aerobic and resistance exercise. The body weight, muscle weight, and bone morphometric microstructure parameter including bone mineral density (BMD), bone specific surface (BS/BV), percent bone volume (BV/TV), trabecular thickness (Tb/Th), trabecular number (Tb/N), trabecular separation (Tb/Sp), structure model index (SMI), connectivity density, and cross-sectional area was evaluated using by microcomputed tomography (micro-CT). One-way repeated ANOVA was used to evaluate the differences between three groups and paired t-test analysis was applied to examine the different between immobilization leg and non-immobilization leg. RESULTS The results of this study indicated that the body weight was increased after 4 weeks, and decreased after 2 weeks immobilization. The gastronemius and soleus muscle weight was significantly decreased in immobilization leg compared to non-immobilization leg. BMD, BV/TV, BS/BV, Tb/Th, Tb/N, Tb/Sp, and Cross-sectional area in immobilization leg of CC was lower than immobilization leg of RT and AE. CONCLUSIONS These results suggest that 4 weeks prior exercise might improve the bone density and microstructure, even though 2 weeks immobilization. Especially, the prior resistance exercise has more beneficial effects on muscle weight, bone density and microstructure. 색인어: ì‚¬ì „ìš´ë™, ìœ ì‚°ì†Œ, ì €í•­, ê³ ì •, 골미세구조 Keywords: Prior exercise, Aerobic, Resistance, Immobilization, Bone microstructure