大菱鲆早期发育过程中免疫器官的发生

应用组织切片研究了大菱鲆(Scophthalmus maximus)初孵仔鱼至60 日龄幼鱼免疫器官的发育过程。结果表明, 免疫器官原基出现的先后顺序是头肾、脾脏和胸腺。1 日龄仔鱼可以观察到头肾原基, 包含未分化的造血干细胞。5 日龄时, 脾脏原基出现, 其淋巴化开始于27 日龄且发育速度较慢。13 日龄时, 大菱鲆仔鱼胸腺原基出现, 且发育速度较快, 分为外区和内区。在大菱鲆早期发育过程中, 胸腺和头肾之间出现细胞迁移现象。免疫器官淋巴化的顺序是胸腺、头肾和脾脏。在免疫器官发育后期, 脾脏和头肾中均发现了黑色素-巨噬细胞中心(MMCs), 脾脏中较丰富, 但在胸腺中尚未发现。在大菱鲆仔鱼早期发育阶段, 免疫器官尚未发育完善, 非特异性防御机制起着重要的免疫作用。

Ontogeny of immune organs during early developmental stages of turbot

A histological study was performed to investigate the development of immune organs in turbot Scophthalmus maximus from hatching to 60 days after hatching (DAH). The temporal sequence of the appearance of immune organ anlages was head kidney, spleen, and thymus. At 1 DAH, head kidney anlage and primordial stem cells were observed. Spleen anlage was present at 5 DAH, became lymphoid at 27 DAH, and developed slowly. Progenitor thymus appeared at 13 DAH, and grew quickly. An outer zone and an inner zone in the thymus were observed. Cell migration occurred between thymus and head kidney. The first functional lymphoid organ was thymus, being followed by head kidney and spleen. During the posterior developmental period of the immune organs, the melano-macrophage centers (MMCs) were not found in thymus, but was found in spleen and head kidney, with higher abundance in spleen. During the early developmental stages of turbot larvae, before the maturity of immune organs, non-specific systems might play an important role in the immunocompetence mechanisms.