Effects of different intensities of treadmill running on bone composition in rats / 中华创伤骨科杂志

ABSTRACT

Objective To evaluate the effects of different intensities of treadmill running on changes in tibial bone composition in a rat model.Methods A total of 24 female Wistar rats were randomly assigned into 4 even groups (n =6) of free movement (FM),low-intensity running (LR),medium-intensity running (MR),and high-intensity running (HR).Rats in LR,MR,and HR groups underwent treadmill running with respective intensities (15 m/min and a 0° gradient,20 m/min and a 5° gradient,25 m/min and a 10° gradient) for 8 weeks (1 h/d and 5 d/week).FM group were taken as controls.The cortical and trabecular bone at the left tibial metaphysis was harvested after 8 weeks in each group for Raman spectroscopy to analyze mineral-matrix ratio,carbonate-phosphate ratio and crystallinity.Results In MR group,the mean mineral-matrix ratio was 4.883 ± 0.128 for cortical bone and 4.216 ±0.213 for trabecular bone,both significantly higher than those in FM group (4.113 ±0.132 and 3.773 ±0.122) (P ＜ 0.05).The mean mineral-matrix ratio was 3.222 ± 0.329 for trabecular bone in HR group,significantly lower than that in FM group (P ＜ 0.05).In MR group,the mean carbonate-phosphate ratio was 0.166 ± 0.013 for trabecular bone,significantly lower than that in FM group (0.177 ± 0.011) (P ＜ 0.05).In HR group,the mean carbonate-phosphate ratio was 0.195 ± 0.012 for cortical bone and 0.187 ± 0.010 for trabecular bone,both significantly higher than those in FM group (0.183 ± 0.014 and 0.177 ± 0.011) (P ＜ 0.05).In HR group,the mean crystallinity was 0.0521 ± 0.0012 for cortical bone and 0.0522 ± 0.0017 for trabecular bone,both significantly higher than those in the other 3 groups (P ＜ 0.05).Conclusions Running with medium intensity may increase bone mineralization and turnover,thus enhancing bone quality.However,running with high intensity may decrease bone mineralization and thus bone quality.