Du Plessis D G, Mouton Y M, Muller C J, Geiger D H
Department of Anatomical Pathology, University of Stellenbosch Medical School, Tygerberg, South Africa.
J Anat. 1996 Dec;189 ( Pt 3)(Pt 3):631-41.
Three phases of perineurial development were recognised in the chicken sciatic nerve: (1) an early primitive phase during which the embryonic perineurium appeared to organise from the surrounding mesenchyme; (2) an intermediate phase of differentiation with the formation of a multilayered cellular network around the Schwann cell-axon complexes, and (3) a final phase of maturation during which the perineurial sheath showed features correlating with those of a functional barrier. Our observations support a mesenchymal origin for the perineurium rather than a schwannian derivation with clear separation of these 2 cell populations during all stages of development. Although the embryonic perineurial cells initially showed a fibroblast-like appearance, distinctive features of perineurial differentiation were present as early as 5 1/2 days (d) (Hamburger & Hamilton stage 28 embryo). Perineurial differentiation appeared to be intimately associated with developmental events in the Schwann cell-axon complexes, particularly during the period of most active Schwann cell proliferation. It is proposed that factors released by the Schwann cell-axon complexes during this period may be responsible for perineurial differentiation and organisation from the surrounding mesenchyme. The presence of endoneurial blood vessels following the appearance of perineurial basal lamina at 17 d (stage 43) suggested the emergence of a perineurial barrier. A perineurial architecture and cytological fine structure comparable to that of the adult animal was, however, only observed in the 10 d-old-chick.
（1）早期原始阶段，在此期间胚胎神经束膜似乎从周围的间充质组织中组织形成；（2）中间分化阶段，在施万细胞 - 轴突复合体周围形成多层细胞网络；（3）最终成熟阶段，在此期间神经束膜鞘表现出与功能性屏障相关的特征。我们的观察结果支持神经束膜起源于间充质，而不是施万细胞起源，并且在发育的所有阶段这两种细胞群体都有明显的分离。尽管胚胎神经束膜细胞最初呈现出成纤维细胞样外观，但早在5.5天（哈伯格和汉密尔顿第28阶段胚胎）就出现了神经束膜分化的独特特征。神经束膜分化似乎与施万细胞 - 轴突复合体中的发育事件密切相关，特别是在施万细胞最活跃增殖的时期。有人提出，在此期间施万细胞 - 轴突复合体释放的因子可能负责神经束膜从周围间充质的分化和组织形成。在17天（第43阶段）神经束膜基底层出现后，有髓神经内血管的存在表明神经束膜屏障的出现。然而，只有在10日龄雏鸡中才观察到与成年动物相当的神经束膜结构和细胞学精细结构。
