Furuoka H, Mizushima M, Miyazawa K, Matsui T
Department of Veterinary Pathology, Obihiro University of Agriculture and Veterinary Medicine, Japan.
Acta Neuropathol. 1994;88(4):389-93. doi: 10.1007/BF00310385.
We report the pathological findings of the skeletal muscle and peripheral nerves from a male 14-months-old thoroughbred horse showing idiopathic knuckling. The affected animal, when in staining position, presented knuckling at the fetlock joint of both forelegs, and dragged both fore- and hindlegs when attempting forward movement. The skeletal muscles demonstrated neurogenic atrophy characterized by the scattering of single angular fibers, groups consisting of five to ten angular fibers, and multiple fascicles of atrophic and hypertrophic fibers. The severity of changes tended to be a distal gradient. While there was no evidence of fiber loss on light microscopy, a diffuse scattering of myelin ovoid, Wallerian-like degeneration and onion-bulb formations were observed in almost all peripheral nerves collected. The characteristic features in electron microscope were swollen axons, which contained accumulations of organelles, especially degenerative mitochondria and neurofilamanets. Onion-bulb formations were frequently found and were associated with Schwann cell processes and occasional collagen pockets. Other prominent feature were Büngner bands which contained myelin debris and regenerating axons or sprouts. These findings suggested that the nature of this disease was a disturbance in axonal transport and were indicative of a distal axonopathy.
我们报告了一匹14个月大的雄性纯种马的骨骼肌和周围神经的病理检查结果，该马表现为特发性指关节屈曲。患病动物在站立姿势时，两个前肢的球节出现指关节屈曲，向前移动时前腿和后腿拖地。骨骼肌显示神经源性萎缩，其特征为单个角形纤维散在分布、由五到十个角形纤维组成的群组以及萎缩和肥大纤维的多个束状结构。变化的严重程度呈远端梯度。虽然在光学显微镜下没有纤维丢失的证据，但在几乎所有采集的周围神经中都观察到髓鞘卵圆形的弥漫性散在分布、类华勒氏变性和洋葱球形成。电子显微镜下的特征性表现为轴突肿胀，其中含有细胞器聚集物，尤其是退化的线粒体和神经丝。经常发现洋葱球形成，且与施万细胞突起和偶尔的胶原囊有关。其他突出特征是含有髓鞘碎片和再生轴突或芽的Büngner带。这些发现表明，这种疾病的本质是轴突运输障碍，提示为远端轴索性神经病。
