Short-time middle-load treadmill exercise affects the bone mineral density of hyperlipidemia male rats / 中国组织工程研究

ABSTRACT

BACKGROUND:Some studies have shown that hyperlipidemia can lead to osteoporosis in rats, and exercise can increase the bone mineral density of rats. But the effect of short-time exercise on the bone mineral density of hyperlipdemia induced osteoporosis male rats is unclear yet. OBJECTIVE:To investigate the effect of short-time middle-load treadmil exercise on the bone mineral density of hyperlipidemia male rats. METHODS:Twenty-six male Sprague Dawley rats were randomly divided into three groupscontrol group (n=8), hyperlipidemia group (n=9) and exercise intervention group (n=9). The rats in the control group were fed with normal diet, and the rats in the other two groups were fed with high-fat diet and lasted for 4 weeks to establish the hyperlipidemia models. The rats in the exercise intervention group received treadmil exercise 5 days per week for 4 weeks according to the fol owing schedule15 m/min for 15 minutes in the 1st week, 15 m/min for 20 minutes in the 2nd week, and then 20 m/min for 20 minutes in the last 2 weeks. Slope grade of the treadmil was adjusted at 0°. At the end of experiment, the rats were sacrificed, and the bone mineral density of the right femur, the morphological change of tibia, the level of plasma alkaline phosphates and calcium content were examined. RESULTS AND CONCLUSION:Compared with the control group, the distal femur bone mineral density in hyperlipidemia group was significantly decreased (P<0.05);histological analysis of the proximal tibia showed thinning and loss of bony trabeculae arrangement, the gap was widened, and a large amount of fat cel s infiltration or integration into vacuoles in the marrow was observed, the plasma alkaline phosphates was significantly increased (P<0.01). Compared with the hyperlipidemia group, distal femur bone mineral density in the exercise intervention group was increased (P<0.05). After adjust body weight, the whole femur bone mineral density was significantly greater in exercise intervention group compared to hyperlipidemia group (P<0.05). The histological analysis of the proximal tibia showed that the spaces of bone trabeculae decreased and the structure of bone trabeculae compacted, the alkaline phosphates activities were increased (P<0.01). There were no significant differences in serum calcium and phosphates levels between groups. The results show that short-time middle-load treadmil exercise can increase the bone mineral density of hyperlipidemia male rats.