Bioscience Journal (Jul 2012)

Free activity in the cage associated with body weight gain restores bone structural and mechanical properties in growing rats after hindlimb unloading

  • Adelton Andrade Barbosa,
  • Ricardo Junqueira Del Carlo,
  • Simone Rezende Galvão,
  • Mário Jefferson Quirino Louzada,
  • Frederico Souzalima Caldoncelli Franco,
  • Bárbara Braga Fernandes,
  • Miguel Araújo Carneiro-Junior,
  • Regiane Maria Soares Ramos,
  • Lucas Rios Drummond,
  • Antonio Jose Natali

Journal volume & issue
Vol. 28, no. 4

Abstract

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We investigated the importance of daily free activity in the cage and body weight gain during the recovering of bone structural and mechanical properties in growing rats after hindlimb unloading. Eight-week-old male Wistar rats were randomly divided into control (CG, n=24) and suspended (SG, n=24) groups. Animals from SG underwent a four-week hindlimb unloading period by tail-suspension. Animals from CG and those from SG after release were kept in collective cages and sacrificed at the age of 12, 16 and 20 weeks. Both femurs were removed and its area, bone mineral density (BMD), resistance to failure and stiffness were determined. Four-week hindlimb unloading decreased (p0.05) the body weight (CG, 472.75 ± 14.11 vs. SG, 444.75 ± 18.91 g), BMD (CG, 0.24 ± 0.01 vs. SG, 0.22 ± 0.01 g/cm2), bone resistance to failure (CG, 195.73 ± 10.06 vs. SG, 178.45 ± 8.48 N) and stiffness (CG, 0.56 ± 0.02 vs. SG, 0.47± 0.03 N/m) of SG animals. Body weight correlated strongly with bone structural and mechanical properties (p

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