@article{oai:nagasaki-u.repo.nii.ac.jp:00027771,
 author = {Koseki, Hironobu and Osaki, Makoto and Honda, Yuichiro and Sunagawa, Shinya and Imai, Chieko and Shida, Takayuki and Matsumura, Umi and Sakamoto, Junya and Tomonaga, Iku and Yokoo, Seiichi and Mizukami, Satoshi and Okita, Minoru},
 issue = {11},
 journal = {PLOS ONE},
 month = {Nov},
 note = {Purpose
Immobilization osteopenia is a major healthcare problem in clinical and social medicine. However, the mechanisms underlying this bone pathology caused by immobilization under load-bearing conditions are not yet fully understood. This study aimed to evaluate sequential changes to the three-dimensional microstructure of bone in load-bearing immobilization osteopenia using a fixed-limb rat model.
Materials and method
Eight-week-old specific-pathogen-free male Wistar rats were divided into an immobilized group and a control group (n = 60 each). Hind limbs in the immobilized group were fixed using orthopedic casts with fixation periods of 1, 2, 4, 8, and 12 weeks. Feeding and weight-bearing were freely permitted. Length of the right femur was measured after each fixation period and bone microstructure was analyzed by micro-computed tomography. The architectural parameters of cortical and cancellous bone were analyzed statistically.
Results
Femoral length was significantly shorter in the immobilized group than in the control group after 2 weeks. Total area and marrow area were significantly lower in the immobilized group than in the control group from 1 to 12 weeks. Cortical bone area, cortical thickness, and polar moment of inertia decreased significantly after 2 weeks. Some cancellous bone parameters showed osteoporotic changes at 2 weeks after immobilization and the gap with the control group widened as the fixation period extended (P < 0.05).
Conclusion
The present results indicate that load-bearing immobilization triggers early deterioration of microstructure in both cortical and cancellous bone after 2 weeks., PLoS ONE, 17(11), art. no. e0275439; 2022},
 title = {Progression of microstructural deterioration in load-bearing immobilization osteopenia},
 volume = {17},
 year = {2022}
}