Lane N E, Kaneps A J, Stover S M, Modin G, Kimmel D B
Rossalind Russell Research Laboratory, Division of Rheumatology, Department of Medicine, Box 0868, University of California at San Francisco, San Francisco, California 94143, USA.
Calcif Tissue Int. 1996 Nov;59(5):401-6. doi: 10.1007/s002239900147.
The purpose of this experiment was to study changes in bone mass, structure, and turnover in the canine forelimb after unilateral immobilization and recovery. The right forelimbs of 14 adult mongrel dogs were immobilized for 16 weeks. Six dogs served as controls. Seven immobilized and three control dogs were euthanized at the end of the immobilization period. Recovery consisted of 16 weeks of kennel confinement followed by 16 weeks of treadmill exercise. Seven once-immobilized and three control dogs were euthanized at the end of the recovery period. Bone mineral density of both the proximal (PBMD) and central (CBMD) radius was determined by dual X-ray absorptiometry. Standard histomorphometric endpoints for bone mass and turnover were determined in the cancellous bone of the proximal radius. After immobilization, PBMD, CBMD, and trabecular thickness were lower in the immobilized limb than in either the contralateral or control limbs (P < 0.05). Only CBMD remained significantly lower (P < 0.05) after recovery. At the end of immobilization, bone formation endpoints were significantly higher in the immobilized limb than both the contralateral and control limbs. Bone turnover was also significantly lower in the contralateral limb than in the immobilized and control limbs. After recovery, all differences in bone turnover had resolved. Immobilization of 16 weeks duration caused an elevation in cancellous bone formation rate and reduced bone density in both cortical and cancellous bone. After 32 weeks of recovery, turnover abnormalities disappeared, cancellous bone normalized, but cortical bone mass remained low. Recovery of cortical bone from immobilization takes longer than recovery of cancellous bone.
本实验的目的是研究单侧固定及恢复后犬前肢骨量、结构和骨转换的变化。14只成年杂种犬的右前肢被固定16周。6只犬作为对照。7只固定的犬和3只对照犬在固定期结束时实施安乐死。恢复过程包括16周的犬舍饲养，随后是16周的跑步机运动。7只曾被固定的犬和3只对照犬在恢复期结束时实施安乐死。通过双能X线吸收法测定桡骨近端（PBMD）和中部（CBMD）的骨密度。在桡骨近端的松质骨中确定骨量和骨转换的标准组织形态学终点。固定后，固定侧肢体的PBMD、CBMD和小梁厚度低于对侧或对照肢体（P<0.05）。恢复后只有CBMD仍显著较低（P<0.05）。在固定结束时，固定侧肢体的骨形成终点显著高于对侧和对照肢体。对侧肢体的骨转换也显著低于固定侧和对照肢体。恢复后，骨转换的所有差异均消失。16周的固定导致松质骨形成率升高，皮质骨和松质骨的骨密度降低。经过32周的恢复，骨转换异常消失，松质骨恢复正常，但皮质骨量仍较低。皮质骨从固定状态恢复所需的时间比松质骨长。
