Little C B, Ghosh P, Rose R
Raymond Purves Bone and Joint Research Laboratories, Royal North Shore Hospital, St. Leonards, NSW, Australia.
Osteoarthritis Cartilage. 1997 May;5(3):161-72. doi: 10.1016/s1063-4584(97)80011-8.
Articular cartilage degeneration in the middle carpal joint is a common problem in racing horses. This study evaluated the effect of exercise on the in-vitro synthesis of the large aggregating proteoglycans (aggrecan) and two small proteoglycans, biglycan and decorin, in articular cartilage taken from three weight bearing regions of the third carpal bone of horses which were subjected to moderate or strenuous exercise. Twelve Standardbred horses free from clinical and radiographic disease of the middle carpal joint were subjected to an 8 week moderate exercise program. The horses were then randomly assigned to two groups: group A--continued moderate exercise and group B--strenuous exercise for 17 weeks. Horses were then rested for 16 weeks. Full-depth articular cartilage explants from the dorsal radial facet (DRF), dorsal intermediate facet (DIF) and palmar condyle (PC) of the third carpal bone were collected and cultured. Cartilage proteoglycan content and release into culture media were measured. Newly synthesized proteoglycans were labeled with 35SO4(2-) for 48 h and analyzed by size exclusion and hydrophobic chromatography, sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis (PAGE) and autoradiography. Histologic sections of adjacent osteochondral regions were evaluated for evidence of arthritic change. No histologic abnormalities or differences in proteoglycan content were detected in any of the articular cartilage regions examined. There was however, a significant reduction (P < 0.05) in aggrecan synthesis and a concomitant increase in decorin synthesis (P < 0.05) in articular cartilage from the DRF of group B animals. There was no change in biglycan synthesis, aggrecan hydrodynamic size or ability to aggregate in any articular cartilage region. This study has demonstrated that strenuous exercise in horses can lead to a disturbance in the biosynthesis of proteoglycans in articular cartilage regions subjected to high contact stresses (DRF). These metabolic abnormalities, which persisted for 16 weeks after cessation of exercise, could have deleterious effects on the biomechanical properties of the tissue. We suggest that the observed alteration in articular cartilage metabolism in CRF cartilage of strenuously exercised horses could represent a predisposing factor for cartilage degeneration and osteoarthritis at a later stage.
腕中关节的关节软骨退变是赛马中常见的问题。本研究评估了运动对取自经历适度或剧烈运动的马第三腕骨三个负重区域的关节软骨中大型聚集蛋白聚糖（聚集蛋白聚糖）以及两种小型蛋白聚糖（双糖链蛋白聚糖和核心蛋白聚糖）体外合成的影响。12匹无腕中关节临床和影像学疾病的标准赛马接受了为期8周的适度运动计划。然后将这些马随机分为两组：A组——继续适度运动，B组——剧烈运动17周。之后让马休息16周。收集并培养取自第三腕骨桡侧背侧小面（DRF）、中间背侧小面（DIF）和掌侧髁（PC）的全层关节软骨外植体。测量软骨蛋白聚糖含量以及释放到培养基中的情况。用35SO4(2-)对新合成的蛋白聚糖进行48小时标记，并通过尺寸排阻色谱法、疏水色谱法、十二烷基硫酸钠（SDS）聚丙烯酰胺凝胶电泳（PAGE）和放射自显影进行分析。评估相邻骨软骨区域的组织学切片以寻找关节炎变化的证据。在所检查的任何关节软骨区域均未检测到组织学异常或蛋白聚糖含量差异。然而，B组动物DRF的关节软骨中聚集蛋白聚糖合成显著减少（P < 0.05），同时核心蛋白聚糖合成增加（P < 0.05）。双糖链蛋白聚糖合成、聚集蛋白聚糖流体力学大小或在任何关节软骨区域的聚集能力均无变化。本研究表明，马的剧烈运动可导致承受高接触应力的关节软骨区域（DRF）中蛋白聚糖生物合成紊乱。这些代谢异常在运动停止后持续16周，可能对组织的生物力学特性产生有害影响。我们认为，在剧烈运动的马的CRF软骨中观察到的关节软骨代谢改变可能是后期软骨退变和骨关节炎的一个易感因素。
