ECTS Abstracts (2015) 1 P25

Influence of obesity on bone tissue of aged Rattus norvegicus albinus submitted to tail suspension and resistance exercise

Ronaldo A Medeiros, Bruna R S M Oliveira, Melise J P Ueno & Mario J Q Louzada

Unesp, Aracatuba, Sao Paulo, Brazil.

In this study, we evaluated the effects that obesity induced by sucrose intake provides in bone tissue of aged male Wistar rats in two opposite situations: in extreme inactivity, and performing strength exercises. Physical inactivity was induced by tail suspension, simulating situations of little or no load on the hindlimbs and the exercises were performed on adapted ladder. 54 male rats with 16 months old were studied. Upon completion 13 months old, 27 rats were randomly selected to receive sucrose-rich diet for 3 months. After this period, they were randomised into three groups: 9 were the Sucrose group (Sa), 9 Sucrose Suspended group (SaSu) and 9 Sucrose Exercise group (SAEx). The remaining 27 animals which didn’t received the sucrose-rich diet were randomly assigned at the end of these 16 months, forming 3 more groups: 9 animals were used as controls (C), 9 Suspended group (Su), and 9 Exercise group (Ex). Analyses were made with densitometer to measure bone mineral content and areal bone mineral density in the femurs and tibias; Mechanical tests of compression of the femoral head, tibial compression and compression of the cortical bone and Immunohistochemical analysis with markings for OCN and TRAP. The results showed obese animals that performed exercises had significant improvement (p<0,05) in BMC of femurs, while non-obese animals that performed exercises showed improvement in BMC of femurs and tibias, aBMD of femurs and tibias, and the maximum allowed force of tibias. The suspended animals had a significant bone quality loss (p<0.05) in all parameters analysed. We can conclude that lack of use of a bone segment in Wistar rats in old age, both obese and non-obese, leads to a rapid weakening of all bone parameters. Exercise provides moderate positive effect in non-obese animals and low positive effect in obese animals.

Disclosure: The authors declared no competing interests.

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