Mechanisms by which high-intensity interval training influences bone health in a rat model of postmenopausal osteoporosis / 中国组织工程研究

ABSTRACT

BACKGROUND:Resistance training and weight-bearing exercise are recommended modes for patients with osteoporosis to improve bone health.High-intensity interval training is a high-impact weight-bearing exercise with obvious time-efficient characteristics;however,little attention has been paid to its impact on bones. OBJECTIVE:To observe the effect of high-intensity interval training on the bone health of ovariectomized rat models. METHODS:Thirty-six female Sprague-Dawley rats were randomly divided into sham group,model group and model exercise group(n=12 per group).Bilateral ovariectomy was used to prepare an osteoporosis rat model in the latter two groups.Six weeks after modeling,the model exercise group was subjected to a high-intensity interval training on an electric treadmill at 90%peak running speed for 2 minutes and 50%peak running speed for 1 minute as one session,a total of nine sessions,3 days per week,for 6 weeks.Rats in the sham and model groups were raised quietly in the mouse cage during the same period.The relevant indexes were tested 48-72 hours after the final training. RESULTS AND CONCLUSION:Compared with the sham group,bone mineral density,maximal load,stiffness,elasticity,trabecular volume fraction,and trabecular number decreased(P<0.05),while trabecular separation increased(P<0.05);the level of irisin in the serum,gastrocnemius and femur decreased(P<0.05);the expression of peroxisome proliferator-activated receptor γ coactivator-1α protein and fibronectin type Ⅲ domain-containing protein 5 mRNA and protein in the gastrocnemius muscle decreased(P<0.05);the expression of type I collagen,Osterix,and Runx2 mRNA in the femur decreased(P<0.05);and the expression of anti-tartrate acid phosphatase,receptor activator of nuclear factor κB ligand,and osteoclast-associated receptor mRNA increased in the model group(P<0.05).Compared with the model group,bone mineral density,fracture load,maximal load,stiffness,elasticity,average trabecular thickness,and trabecular number increased(P<0.05),and trabecular separation decreased(P<0.05);the level of irisin in the serum,gastrocnemius and femur increased(P<0.05);the expression of peroxisome proliferator-activated receptor γ coactivator-1α protein and fibronectin type Ⅲ domain-containing protein 5 mRNA and protein in gastrocnemius increased(P<0.05);the expression of type I collagen,Osterix,and Runx2 mRNA in the femur increased(P<0.05);and the expression of anti-tartrate acid phosphatase,receptor activator of nuclear factor κB ligand,and osteoclast-associated receptor mRNA decreased in the model exercise group(P<0.05).To conclude,short-term high-intensity interval training may improve bone health of ovariectomized rats through up-regulating the irisin level.