Effects of high‐impact exercise on the physical properties of bones of ovariectomized rats fed to a high‐protein diet

Abstract

The aim of this study was to evaluate the effects of high-impact physical exercise as a prophylactic and therapeutic means in osteopenic bones of rats submitted to ovariectomy and protein diet intake. A total of 64 Wistar rats were divided into eight groups (n = 8 each), being: OVX, ovx, standard diet and sedentary; OVXE, ovx, standard diet and jump; OVXP, ovx, high-protein diet and sedentary; and OVXEP, ovx, high-protein diet and jump; SH, sham, standard diet and sedentary; SHE, sham, standard diet and jump; SHP, sham, high-protein diet and sedentary; and SHEP, sham, high-protein diet and jump. OVX surgery consists of ovariectomy, and sham was the control surgery. The jumping protocol consisted of 20 jumps/day, 5 days/week. The bone structure was evaluated by densitometry, mechanical tests, histomorphometric, and immunohistochemical analyses. A high-protein diet resulted in increased bone mineral density (P = .049), but decreased maximal load (P = .026) and bone volume fraction (P = .023). The benefits of physical exercise were demonstrated by higher values of the maximal load in the trained groups compared to the sedentary groups (P < .001). The sham groups had decreased immunostaining of osteocalcin (P = .004) and osteopontin (P = .010) compared to ovx groups. However, the high-protein diet (P = .005) and jump exercise (P = .017) resulted in lower immunostaining of osteopontin compared to the standard diet and sedentary groups, respectively. In this experimental model, it was concluded that ovariectomy and a high-fat diet can negatively affect bone tissue and the high-impact exercise was not enough to suppress the deleterious effects caused by the protein diet and ovariectomy.

Aerobic Exercise Increases the Damage to the Femoral Properties of Growing Rats with Protein-Based Malnutrition

“…The main consequence of such diet was that it impaired femoral mechanical and densitometric properties. The bone tissue is composed of around one third of proteins [23], which influences bone mineral content [9]. Indeed, while a protein-based diet has been positively associated with bone quality [24][25][26][27], the reduction of protein intake has been associated with increased risk for osteoporosis [26,28].…”

“…Physical exercise has been indicated for the prevention and non-pharmacological treatment of osteopenia and osteoporosis, as it generates necessary mechanical osteogenic stimuli with few side effects 9. Studies have demonstrated that systematic physical exercises can improve bone properties such as strength, bone mineral content and density [9,10]. Furthermore, it is indicated that physical activities performed in the childhood and adolescence favor the accumulation of minerals in the bones and contribute to the bone health in the adulthood [11].…”

Doxycycline reduces osteopenia in female rats

“…The left femora were submitted to densitometric analysis using “dual-energy” x-ray densitometer equipment, Alpha, Lunar DPX ® (Lunar, Madison, WI, United States) installed at the School of Medicine of Ribeirao Preto. Adapted for measurement small animals with the PIXImus software (Lunar, Madison, WI, United States) 49,50 . The image acquisition is proceeded with the femurs (distal portion of the femur) position with ROI of 9 mm² (Fig.…”

“…The software used for statistical analysis was SPSS 20.0 (IBM, New York, NY, USA) and the samples were submitted to the general linear model test, and all comparisons were submitted to Bonferroni adjustment 24,49 . Analysis of TRAP were subjected to normality test and then it was subjected to nonparametric test with Kruskal Wallis as analysis of variance, with a post-test of Dunn that was held to specify these differences.…”