Differential effect of treadmill exercise on three cancellous bone sites in the young growing rat
Authors: J F Aloia
J Iwamoto
J K Yeh
Journal: Bone (1999)
Discipline: CLINICAL MEDICINE
Keywords: cancellous bone; exercise; skeletal sites; young growing rat; treadmill running

Abstract:  The aim of the present study was to examine cancellous bone changes induced by exercise on three different skeletal sites, the lumbar vertebra, the proximal, and the distal tibia, in the young growing rat. Forty 4-week-old female Sprague-Dawley rats were randomized into 4 groups of 10 animals each; 8 weeks exercise (8EX), 8 weeks sedentary control (8CON), 12 weeks exercise (12EX), and 12 weeks sedentary control (12CON). The exercise regimen consisted of treadmill running at 24 m/min 1 hr per day 5 days a week. After each period of exercise, the proximal and distal tibial metaphyses (PTM and DTM, respectively) and the fifth lumbar (L5) vertebral body were processed for histomorphometry of the cancellous bone (secondary spongiosa) and cortical periosteum. Eight and twelve weeks of exercise significantly increased the mineral apposition rate and bone formation rate in the PTM and DTM, and 12 weeks of exercise significantly increased the labeled perimeter in the DTM, compared with the age-matched controls. Eight and twelve weeks of exercise significantly increased cancellous bone volume in the PTM (mean +/- standard deviation, 8EX; 19.1 +/- 2.9% vs 8CON; 14.3 +/- 3.1%, P &lt; 0.05 and 12EX; 18.8 +/- 3.5% vs 12CON; 15.2 +/- 3.3%, P &lt; 0.05), and 12 weeks exercise significantly increased cancellous bone volume in the DTM, compared with age-matched control (12EX; 32.5 +/- 7.7%, 12CON; 22.2 +/- 4.8%, P &lt; 0.05). The increase in cancellous bone volume by 12 weeks exercise was higher in the DTM than that in the PTM (43.4% and 24.0%, respectively). On the other hand, the exercise did not significantly affect cancellous bone volume and bone formation in the L5 vertebral body, although the cortical periosteal bone formation rate and the L5 vertebral bone mass were increased. These findings suggest that cancellous bone adaptation to treadmill exercise is site specific, and the effect may be influenced by factors such as mechanical loading and metaphyseal bone architecture in the young growing rat. 

Retracted: No

PubPeer comments:
 2019 expression of concern. https: www.sciencedirect.com science article pii S8756328219303084 Expression of concern regarding Iwamoto J, Yeh JK, Aloia JF. Differential effect of treadmill exercise on three cancellous bone sites in the young growing rat. Bone. 1999;24(3); 163u2013169, 10.1016 S8756-3282(98)00189-6 The editors of BONE issue this expression of concern regarding the above paper for the following reasons: 1. We are now aware of significant scientific overlap between this paper and a subsequent paper in the Journal of Bone and Mineral Research (Iwamoto J, Yeh JK, Aloia JF. Effect of deconditioning on cortical and cancellous bone growth in the exercise trained young rats. J Bone Miner Res. 2000;15(9):1842u20131849). 2. Despite an estimated 62% of the data in the Journal of Bone and Mineral Research paper being already reported in the BONE paper, there are substantial discrepancies in statistical testing and conclusions of individual experiments between the two papers which cannot be resolved at this time. ,