Watanabe Takafumi, Hosaka Yoshinao, Yamamoto Etsuko, Ueda Hiromi, Sugawara Kenji, Takahashi Heishichiro, Takehana Kazushige
Department of Veterinary Anatomy, School of Veterinary Medicine, Rakuno Gakuen University, Hokkaido, Japan.
J Vet Med Sci. 2005 Sep;67(9):855-60. doi: 10.1292/jvms.67.855.
The distribution pattern of collagen fibril diameter in the equine superficial digital flexor tendon (SDFT) is known to differ in central and peripheral areas of some regions. This study reports the essence of collagen fibril differences among different regions of the equine SDFT by transmission electron microscopic (TEM) and high-voltage electron microscopic observations and biochemical analysis. The distribution of large collagen fibrils increased but the density of collagen fibrils decreased from the proximal metacarpal region to the distal metacarpal region. Large collagen fibrils with an irregular cross-sectional profile were found more frequently in the middle metacarpal region than in other regions. Three-dimensional reconstruction of images of irregularly shaped collagen fibrils revealed that these fibrils are formed through fusion of small collagen fibrils with large ones. The amount of decorin, which reportedly inhibits the lateral fusion of collagen fibrils, decreased in the direction of the distal metacarpal region. On the other hand, the size of decorin gradually increased in the direction of the distal metacarpal region. These results suggest that regional differences in collagen fibril distribution and density of collagen fibrils in the SDFT are due, at least in part, to fusion of collagen fibrils and the concomitant regional differences in the amount and size of decorin.
已知马的指浅屈肌腱（SDFT）中胶原纤维直径的分布模式在某些区域的中央和周边有所不同。本研究通过透射电子显微镜（TEM）、高压电子显微镜观察及生化分析，报告了马SDFT不同区域之间胶原纤维差异的本质。从掌骨近端区域到掌骨远端区域，大胶原纤维的分布增加，但胶原纤维的密度降低。在掌骨中部区域比其他区域更频繁地发现具有不规则横截面轮廓的大胶原纤维。对不规则形状胶原纤维图像的三维重建显示，这些纤维是通过小胶原纤维与大胶原纤维融合形成的。据报道，可抑制胶原纤维横向融合的核心蛋白聚糖的量在掌骨远端区域方向上减少。另一方面，核心蛋白聚糖的大小在掌骨远端区域方向上逐渐增加。这些结果表明，SDFT中胶原纤维分布和胶原纤维密度的区域差异至少部分归因于胶原纤维的融合以及核心蛋白聚糖的量和大小的伴随区域差异。
