Effects of voluntary running exercise on bone histology in type 2 diabetic rats

Abstract

The incidence of obesity in children and adolescents, which may lead to type 2 diabetes, is increasing. Exercise is recommended to prevent and improve diabetes. However, little is known about the bone marrow environment at the onset of diabetes in the young, and it is unclear whether exercise training is useful for maintaining bone homeostasis, such as mechanical and histological properties. Thus, this study clarified the histological properties of bone and whether exercise contributes to maintaining bone homeostasis at the onset of type 2 diabetes in rats. Four-week-old male Otsuka Long-Evans Tokushima Fatty (OLETF; n = 21) rats as a diabetic model and Long-Evans Tokushima Otsuka (LETO; n = 18) rats as a control were assigned randomly to four groups: the OLETF sedentary group (O-Sed; n = 11), OLETF exercise group (O-Ex; n = 10), LETO sedentary group (L-Sed; n = 9), and LETO exercise group (L-Ex; n = 9). All rats in the exercise group were allowed free access to a steel running wheel for 20 weeks (5–25 weeks of age). In the glucose tolerance test, blood glucose level was higher in the O-Sed group than that in the L-Sed and L-Ex groups, and was markedly suppressed by the voluntary running exercise of O-Ex rats. The energy to fracture and the two-dimensional bone volume at 25 weeks of age did not differ significantly among the groups, though the maximum breaking force and stiffness were lower in OLETF rats. However, bone marrow fat volume was greater in O-Sed than that in L-Sed and L-Ex rats, and was markedly suppressed by wheel running in the O-Ex rats. Our results indicate that exercise has beneficial effects not only for preventing diabetes but also on normal bone remodeling at an early age.

Exercise improves bone formation by upregulating the Wnt3a/β-catenin signalling pathway in type 2 diabetic mice

“…Despite such benefits, existing studies have focused on the impact of exercise on the T2DM bone phenotype (such as BMD, biomechanical indicators, and others.). After 20 weeks of voluntary running, the maximum breaking force and stiffness of bone histology indexes in type 2 diabetic rats were improved [ 42 ], and 6 weeks treadmill exercise (10 m/min, 60 min/day, 5 days/week) could improve femoral BMD [ 1 ]. There is a scarcity of studies on the effects of different kinds of exercise on the morphological structure of bone tissue in T2DM mice.…”

Long-term physical inactivity exacerbates hindlimb unloading-induced muscle atrophy in young rat soleus muscle

“…The bone mechanical strength of the right femur at midshaft was assessed with a three-point bending test, as previously described (26). Connective tissue was removed, and the bone was mounted on two support stands 10.6 mm apart.…”

Exercise Improves Bone Formation by Upregulating the Wnt3a/β-catenin Signalling Pathway in Type 2 Diabetic Mice

“…However, current studies focus on the impact of exercise on the T2DM bone phenotype (such as BMD, biomechanical indicators, etc.). After 20 weeks of voluntary running, the maximum breaking force and stiffness of bone histology indexes in type 2 diabetic rats were improved (Takamine et al, 2018), and 6 weeks treadmill exercise (10 m/min, 60 min/day, 5 days/week) could improve femoral BMD (Akagawa et al, 2018). There are few reports on the effects of different kinds of exercise on the morphological structure of bone tissue in T2DM mice.…”