Strocchi R, Leonardi L, Guizzardi S, Marchini M, Ruggeri A
J Anat. 1985 Jan;140 ( Pt 1)(Pt 1):57-67.
An investigation was carried out on the sheaths which envelop rat tail tendons. The samples were processed for observation by light and electron microscopy. In the case of electron microscopy, thin sections of specimens embedded in epoxy resin and replicas of freeze etched samples were used. On the basis of histological and ultrastructural observations, four distinct connective tissue sheaths have been detected. The paratendineum is a thick fibrous sheath that covers externally the four groups of tendons arranged around the vertebrae of the tail; the epitendineum is a distinct fibrous sheath surrounding each tendon group; the peritendineum is composed of concentric cellular laminae enveloping each tendon; lastly, the endotendineum is made up of one cellular lamella which adheres to the fibres of the tendon, projecting trabeculae between the individual tendon fascicles. In the para- and epitendineum, thick bundles of collagen fibrils, running parallel to the fibres of the tendon, were visible. The collagen fibrils had a wide variability of diameters (from 35 to 220 nm) and, when examined in replica, their microfibrillar arrangement appeared to be straight. In the peri- and endotendineum, thin bundles of collagen fibrils were visible between the cellular laminae, parallel to the main axis of the tendon. Among these collagen bundles, elastic fibres and numerous glycoproteins containing microfibril-like filaments were visible. The collagen fibrils were small and of uniform diameter (50 nm) and, when observed on replica, showed a helicoidal microfibrillar arrangement. The cell layers of the peri- and endotendineum were made up of flattened fibroblasts which were connected by specialised junctions and which contained numerous micropinocytotic vesicles. A thin layer of granular electron-dense material, with ultrastructural characteristics similar to those of a basement membrane, was visible on the surface of the most external cellular layer of the peritendineum and on the outer surface of the cellular lamella of the endotendineum. Due to their morphological characteristics it is supposed that the four tendon sheaths are involved in different and special functions. Moreover, collagen Type I and collagen Type III, demonstrated by means of immunofluorescence techniques in previous investigations, show respectively a close similarity in distribution to the thick collagen fibrils, with a straight microfibrillar arrangement, of the two external sheaths, and to the thin collagen fibrils, with a helicoidal microfibrillar arrangement, of the two internal sheaths.
对包裹大鼠尾腱的腱鞘进行了一项研究。对样本进行处理，以便用光镜和电镜观察。在电镜观察中，使用了嵌入环氧树脂的标本薄片和冷冻蚀刻样品的复制品。基于组织学和超微结构观察，已检测到四种不同的结缔组织鞘。腱旁组织是一层厚厚的纤维鞘，从外部覆盖围绕尾椎排列的四组肌腱；腱外膜是围绕每组肌腱的一层明显的纤维鞘；腱周组织由包裹每条肌腱的同心细胞层组成；最后，腱内膜由一层附着在肌腱纤维上的细胞层组成，在各个肌腱束之间伸出小梁。在腱旁组织和腱外膜中，可以看到与肌腱纤维平行排列的粗大胶原纤维束。胶原纤维的直径变化很大（从35到220纳米），在复制品中观察时，它们的微原纤维排列似乎是直的。在腱周组织和腱内膜中，在细胞层之间可以看到与肌腱主轴平行的细胶原纤维束。在这些胶原束中，可以看到弹性纤维和许多含有微原纤维样细丝的糖蛋白。胶原纤维细小且直径均匀（50纳米），在复制品上观察时，显示出螺旋状微原纤维排列。腱周组织和腱内膜的细胞层由扁平的成纤维细胞组成，这些细胞通过特殊的连接相连，并含有许多微吞饮小泡。在腱周组织最外层细胞层的表面和腱内膜细胞层的外表面，可以看到一层薄的颗粒状电子致密物质，其超微结构特征与基底膜相似。由于它们的形态特征，推测这四种肌腱鞘具有不同的特殊功能。此外，在先前的研究中通过免疫荧光技术证实的I型胶原和III型胶原，分别在分布上与两个外部鞘中具有直微原纤维排列的粗大胶原纤维以及与两个内部鞘中具有螺旋状微原纤维排列的细小胶原纤维密切相似。
