Birch H L, Bailey A J, Goodship A E
Veterinary Basic Sciences, Royal Veterinary College, North Mymms, Hatfield, UK.
Equine Vet J. 1998 Nov;30(6):534-9. doi: 10.1111/j.2042-3306.1998.tb04530.x.
Injuries to the superficial digital flexor tendon are common in horses required to gallop and jump at speed. Partial rupture of this tendon usually occurs in the central core of the midmetacarpal region and may be preceded by localised degenerative changes. Post mortem examination of apparently normal equine flexor tendons has revealed an abnormal macroscopic appearance in the central core, characterised by a reddish discolouration. We have previously shown that there is also physical damage to the collagen fibres. In the present study we tested the hypothesis that the abnormal appearance is accompanied by changes in the composition of the extracellular matrix of the tendon. Biochemical analysis of the extracellular matrix demonstrated an increase in total sulphated glycosaminoglycan content, increase in the proportion of type III collagen and decrease in collagen linked fluorescence in the central core of 'degenerated' tendons relative to tissue from the peripheral region of the same tendon. Dry matter content and total collagen content were not significantly different between tendon zones or normal and 'degenerated' tendons. These changes suggest a change in cell metabolism and matrix turnover in the central core of the tendon and are likely to contribute to a decrease in mechanical properties in this part of the tendon, predisposing to the characteristic partial rupture of the tendon.
在需要快速奔跑和跳跃的马匹中，指浅屈肌腱损伤很常见。该肌腱的部分断裂通常发生在掌骨中部区域的中央核心部位，且可能在局部退行性改变之前出现。对看似正常的马屈肌腱进行尸检发现，中央核心部位有异常的宏观外观，其特征为发红变色。我们之前已经表明，胶原纤维也存在物理损伤。在本研究中，我们检验了这样一个假设，即这种异常外观伴随着肌腱细胞外基质成分的变化。对细胞外基质的生化分析表明，相对于同一肌腱周边区域的组织，“退化”肌腱中央核心部位的总硫酸化糖胺聚糖含量增加、III型胶原比例增加以及胶原交联荧光减少。肌腱不同区域之间或正常与“退化”肌腱之间的干物质含量和总胶原含量没有显著差异。这些变化表明肌腱中央核心部位的细胞代谢和基质更新发生了改变，并且可能导致该部位肌腱力学性能下降，从而易引发该肌腱特有的部分断裂。
