Pead M J, Suswillo R, Skerry T M, Vedi S, Lanyon L E
Department of Anatomy, Royal Veterinary College, (University of London), UK.
Calcif Tissue Int. 1988 Aug;43(2):92-6. doi: 10.1007/BF02555153.
Both ulnas of skeletally mature roosters (Gallus domesticus) were deprived of functional load bearing by proximal and distal submetaphyseal osteotomies. Twenty-four hours later the animals were injected with 1.5 mCi of 3H-uridine and the ulna on one side was subjected to a single period of a cyclical load engendering physiological strain levels at 1 Hz for 6 min. Twenty-four hours after loading the animals were killed. Autoradiographic examination of comparable regions of cortex in sections from the bone's midshafts showed that in the loaded bones, 72 +/- 2.7% of osteocytes were labeled compared with 12 +/- 3.5% in the corresponding areas of their contralateral nonloaded pair (P less than 0.001). The number of grains per labeled osteocyte was also higher in the loaded side (6 +/- 0.5 compared with 4 +/- 0.5, P less than 0.01). There was no obvious correlation between the longitudinal strain distribution during artificial loading and the distribution of labeled osteocytes throughout the bone cross-section. However, previous long-term experiments using a similar loading preparation had consistently shown the site of most periosteal new bone formation to also not be directly related to the local strain magnitude. Perhaps it is significant that the greatest percentage of labeled cells were found in the cortex where the long-term experiments had shown most new bone formation to subsequently occur.
对骨骼成熟的公鸡（家鸡）的双侧尺骨，通过近侧和远侧干骺端下截骨术使其失去功能性负重。24小时后，给这些动物注射1.5毫居里的3H-尿苷，然后对一侧的尺骨施加一个周期的循环负荷，频率为1赫兹，持续6分钟，产生生理应变水平。负荷后24小时将动物处死。对取自骨干中部的切片中皮质的可比区域进行放射自显影检查显示，在加载负荷的骨骼中，72±2.7%的骨细胞被标记，而在其对侧未加载负荷的相应区域中这一比例为12±3.5%（P<0.001）。加载侧每个被标记骨细胞的银粒数也更高（分别为6±0.5和4±0.5，P<0.01）。人工加载过程中的纵向应变分布与整个骨横截面上被标记骨细胞的分布之间没有明显的相关性。然而，以前使用类似加载准备的长期实验一直表明，大多数骨膜新骨形成的部位也与局部应变大小没有直接关系。也许值得注意的是，在皮质中发现标记细胞的比例最高，而长期实验表明随后大多数新骨形成都发生在该部位。
