Author(s): CARIATI, I., BONANNI, R., ROMAGNOLI, C., DARCANGELO, G., ANNINO, G., TANCREDI, V., Institution: UNIVERSITY OF ROME TOR VERGATA, Country: ITALY, Abstract-ID: 2117

INTRODUCTION:
The aging process compromises bone tissue integrity and predisposes to the onset of diseases, such as osteoporosis, characterized by a progressive impairment of bone microarchitecture associated with increased oxidative stress and altered expression of bone growth regulators. In this context, appropriately designed whole body vibration (WBV) protocols are known to significantly improve bone quality in 4-month-old young mice by increasing the expression of irisin, a myokine with osteoinductive power produced by skeletal muscle in response to exercise. In contrast, little is known about the effects of WBV on bone health in adult and elderly rodents, suggesting that further studies are needed to determine its efficacy in preventing and counteracting age-related bone loss. Based on this evidence, the aim of this study was to investigate skeletal adaptations to WBV in young, adult and old mouse models, assessing any differences in terms of structural, ultrastructural and metabolic changes.
METHODS:
4-, 12- and 24-month-old mice were sacrificed after a three-weekly training with a WBV protocol characterized by three series of mechanical vibrations of 2.30 min, interspersed with a 2.30-min recovery period. Bone tissue samples from the spine were taken from each animal for histological and immunohistochemical analysis, measuring the main morphometric parameters of the bone and investigating the expression of some important markers of bone health, such as fibronectin type III domain-containing protein 5 (FNDC5), NADPH Oxidase 4 (NOX4) and sirtuin 1 (SIRT1). Groups of mice of the same age were maintained under sedentary conditions and sacrificed at the same time as the intervention group mice.
RESULTS:
Mice subjected to WBV were characterized by significantly better bone parameters than the corresponding sedentary mice. Particularly, vibratory training promoted an increase in bone volume and trabecular thickness in association with a reduction in trabecular separation, preserving the ultrastructural characteristics of bone tissue. Interestingly, FNDC5 and SIRT1 were more highly expressed in mice exposed to WBV, while a reduction in the levels of NOX4, an indicator of oxidative stress, was found in the bone tissue of all trained groups, with differences according to age group.
CONCLUSION:
An appropriate WBV protocol could represent a valid alternative strategy to prevent and counteract bone mass loss in adults and the elderly by reducing oxidative stress and positively regulating myokines with osteoinductive power.