Effects of resistance exercise training on bone physical and mineral properties in rats submitted to growth hormone intervention

Purpose: To investigate the effects of applying growth hormone (GH) and performing a strength training protocol on mineralization, rigidity, and crystallinity on the bone tissue of Wistar rats. Method: In total, 40 male animals, 60 days old, of the Wistar lineage were used, distributed into four groups: control (C) [n = 10], control and application of GH (GHC) [n = 10], resistance training (T) [n = 10], and resistance training and application of GH (GHT) [n = 10]. The training period lasted four weeks and consisted of four sets of 10 jumps in a liquid medium. The amount of 0.2 IU per kilogram of body mass (0.2 IU/Kg) of GH was administered in the GHC and GHT groups. After the experimental period, samples of the tibia were collected and analyzed using Raman Spectroscopy (633 nm), Bone Densitometry - dual-energy x-ray absorptiometry (DXA), and Mechanical Assay (F-max). Results: The GHT group presented an increase for the variable Amide II (1544 cm-1) and decrease for the variable Proline (727 cm-1) from the Raman Spectroscopy analysis (p < 0.05). In addition, an increase was observed for the variables bone mineral density (BMD) and bone mineral content (BMC) (p < 0.05). Finally, no statistically significant differences were observed for the variables mineralization, crystallinity, phosphate carbonate types A and B, and bone rigidity (p > 0.05). Conclusion: It is concluded that GH added to RT resulted in an increase in the mineral Amide II (1544 cm-1) and a decrease in Proline (727 cm-1). Furthermore, an increase in BMD and BMC was observed only in the GHT group. Finally, no alterations were observed in crystallinity and rigidity in the different groups of animals.