The osteogenic effects of swimming on bone mass, strength, and microarchitecture in rats with unloading-induced bone loss

Abstract

The effect of nonweight-bearing exercise on osteoporotic bones remains controversial and inconclusive. The purpose of this study was to evaluate the effects of swimming on osteoporotic tibias of rats submitted to hindlimb suspension. Initially, 20 Wistar rats were used to confirm a significant bone loss following 21 days of unloading. Thirty rats were then divided into 3 groups and followed during 51 days: CON (nonsuspended rats), S + WB (suspended rats for 21 days and then released for regular weight-bearing) and, S + Swim (suspended rats for 21 days and then released from suspension and submitted to swimming exercise). We observed that swimming exercise was effective at fully recovering the bone deterioration caused by suspension, with significant increments in BMD, bone strength and bone volume. On the other hand, regular weight-bearing failed at fully restoring the bone loss induced by unloading. These results indicate that swimming exercise may be a potential tool to improve bone density, strength, and trabecular volume in tibias with bone loss induced by mechanical unloading in suspended rats. We conclude that this modality of activity could be beneficial in improving bone mass, strength, and architecture in osteoporotic individuals induced by disuse, such as bed rest or those exposed to microgravity, who may not be able to perform weight-bearing exercises.

Influence of high-fat diet on bone tissue: An experimental study in growing rats

“…The distance between the points was 25 mm, and a pre-load of 5 N for 30 seconds was used based on the recommendations found in [22][23][24].…”

Compromised Exercise Capacity and Mitochondrial Dysfunction in the Osteogenesis Imperfecta Murine (oim) Mouse Model

“…In young and mature rodents, treadmill/voluntary wheel‐running exercise improved BMD, bone microarchitecture, and biomechanical strength, and was protective against estrogen‐deficiency‐induced bone loss . Non‐weight‐bearing‐swimming exercise also prevented bone loss associated with ovariectomy or hindlimb suspension . In the following study, we investigated the effect of weight‐bearing (voluntary wheel‐running) and non‐weight‐bearing‐ (swimming) physical activity on musculoskeletal mass and strength in wild type (WT) and homozygous OI murine ( oim/oim ) mice.…”

“…(19,20) Non-weightbearing-swimming exercise also prevented bone loss associated with ovariectomy or hindlimb suspension. (21)(22)(23) In the following study, we investigated the effect of weight-bearing (voluntary wheel-running) and non-weight-bearing-(swimming) physical activity on musculoskeletal mass and strength in wild type (WT) and homozygous OI murine (oim/oim) mice. Gentry and colleagues were the first to identify an intrinsic muscle pathology in OI by demonstrating that oim/oim mice have reduced specific muscle contractile function (described as the peak tetanic force normalized to myofiber cross sectional area) as compared with WT littermates.…”

Effects of aerobic, anaerobic, and concurrent training on bone mineral density of rats

“…In addition, exercise promotes metabolic and hormonal alterations that also stimulate the synthesis of calcium in bone tissue [15][16][17] . Thus, the aquatic exercise-induced increase in mineral density (ET8 group) could be explained by the mechanical stress caused by the tendon traction on the bones during muscle contraction, together with the metabolic and hormonal alterations caused by exercise.…”

“…Therefore, it is suggested that this type of exercise can be used in conditions of severe loss of bone mass as a method of treatment, especially in cases with a high-risk of fractures, as the reduced impact on the bones from this exercise modality makes practitioners less susceptible to bone fractures 12,17 . With respect to the anaerobic training, it presented higher osteogenic potential than aerobic training (swimming) since after just four weeks, it was able to significantly increase BMD with respect to the aerobic swimming training groups (ET4) and the group without training (BL), and the same occurred with concurrent training.…”