Säämänen A M, Tammi M, Jurvelin J, Kiviranta I, Helminen H J
Department of Anatomy, University of Kuopio, Finland.
J Orthop Res. 1990 Nov;8(6):863-73. doi: 10.1002/jor.1100080612.
The distribution of proteoglycans (PGs) at 11 sites on the knee (stifle joint) cartilage of young female beagle dogs was studied following cast immobilization for 11 weeks in 90 degrees flexion and after a subsequent remobilization for 15 weeks. Immobilization induced a reduction in PG uronic acid at all sites (mean of -38%), but the greatest depletion (-64%) occurred at the anterior and posterior extremes of the femoral condyles, i.e., at locations where the immobilized cartilage lost contact to the opposing cartilage. Following remobilization, the content of uronic acid remained lower than in the age-matched controls (-18% on average), particularly at the minimum contact sites most affected by immobilization (-33%). The chondroitin-6-sulfate to chondroitin-4-sulfate ratio was reduced by immobilization in most locations (average of -14%) and returned to control values after remobilization. There was no consistent change in the percentage of aggregating PGs observed in Sephacryl S-1000 gel filtration after immobilization or remobilization. However, following remobilization, the aggregating PGs showed an enhanced proportion of the slower mobility band in agarose gel electrophoresis, indicative of a larger monomer size. In the contralateral, load-bearing knee joint, both the uronic acid content and PG monomer type distribution were identical to those observed in the experimental joint, suggesting that the state reached after the remobilization period was due to factor(s) influencing both sides. The results suggest that contact forces between articulating surfaces are required to maintain normal PG content and that the control mechanism works locally at each cartilage site. Restriction of joint mobility and loading in young animals is concluded to cause persistent changes in cartilage matrix. Furthermore, the use of the contralateral joint as the sole control in this kind of studies, although experimentally convenient, seems not to be appropriate.
对年轻雌性比格犬的膝关节（ stifle关节）软骨上11个位点的蛋白聚糖（PGs）分布进行了研究，这些犬在90度屈曲位石膏固定11周后，随后再活动15周。固定导致所有位点的PG糖醛酸减少（平均减少38%），但最大的减少（-64%）发生在股骨髁的前后两端，即固定的软骨与相对软骨失去接触的部位。再活动后，糖醛酸含量仍低于年龄匹配的对照组（平均低18%），特别是在受固定影响最大的最小接触位点（-33%）。在大多数部位，固定使硫酸软骨素-6-硫酸盐与硫酸软骨素-4-硫酸盐的比例降低（平均降低14%），再活动后恢复到对照值。在固定或再活动后，通过Sephacryl S-1000凝胶过滤观察到的聚集PGs百分比没有一致变化。然而，再活动后，聚集PGs在琼脂糖凝胶电泳中显示出迁移较慢条带的比例增加，表明单体尺寸更大。在对侧负重膝关节中，糖醛酸含量和PG单体类型分布与实验关节中观察到的相同，这表明再活动期后达到的状态是由影响两侧的因素导致的。结果表明，关节表面之间的接触力是维持正常PG含量所必需的，并且控制机制在每个软骨位点局部起作用。得出结论，限制幼年动物的关节活动和负荷会导致软骨基质持续变化。此外，在这类研究中使用对侧关节作为唯一对照，虽然在实验上方便，但似乎不合适。
