Treadmill exercise can significantly improve bone metabolism in osteoporosis / 中华物理医学与康复杂志

ABSTRACT

Objective To study the effect of treadmill exercise on the bone metabolism of osteoporotic rats and the regulatory role of Wnt/β-catenin signaling in it. Methods Thirty-two female Sprague-Dawley rats aged 2 months were randomly divided into a sham-operated quiet group ( S group ) , an ovariectomized quiet group ( O group) , a sham-operated exercise group ( ST group) and an ovariectomized exercise group ( OT group) with 8 rats in each group. The ovariectomies established a model of post-menopausal osteoporosis. The ovaries of groups O and OT were removed, while those of the S and ST groups were exposed, but not removed. All of the rats were free to move in their cages, but those in the ST and OT groups also underwent treadmill training every day for 10 weeks. All of the rats were sacrificed 24 hours after the last exercise session. Bone mineral density ( BMD) of the femur was measured using dual energy X-ray absorptiometry, while serum calcium, phosphorus and alkaline phosphatase were detected with a biochemical analyzer. Serum osteocalcin was quantified by radioimmunoassay. A three point bending test quan-tified the biomechanical properties of the femors. The expression of Wnt/β-catenin was measured through western blotting. Results After the intervention the average BMD of group O was significantly lower than that of group S, that of group ST was significantly higher than group S and that of group OT significantly higher than group O ( P≤0.05) . The relative expression of Wnt/β-catenin protein P-GSK-3βin group ST was significantly lower than in group S ( P≤0.05) . The relative expressions ofβ-catenin and cyclin D1 in group ST were significantly higher than in group S ( P≤0.05) . The relative expression of protein P-GSK-3βin group OT was significantly lower than in group O, while that of β-catenin and cyclin D1 was significantly higher (P≤0.05). Conclusion Treadmill exercise can signifi-cantly improve bone metabolism in osteoporotic rats. The mechanism may be related to activating the Wnt/β-catenin signaling pathway.