牙鲆胸腺的组织学研究

A Histology Study of the Thymus of Flounder,Paralichthys olivaceus

牙鲆的胸腺位于鳃腔背面结缔组织膜上,紧贴着肾脏的头部,界限清晰,胸腺不向咽腔突出,胸腺上皮没有粘液细胞。牙鲆胸腺没有明显的外区和内区之分,胸腺细胞和巨噬细胞比较均匀地分布于整个组织中,未能观察到胸腺小体。在胸腺的细胞类型上,首次发现了大量的交错突细胞,常与淋巴细胞相伴,其特点是具有大量的”迷路样”膜结构。同时还发现,牙鲆胸腺可以不对称并存在快速退化现象,在3月龄时最易观察,而6月龄以上的牙鲆即退化消失。

The thymus of flounder, Paralichthys olivaceus lies adjacent to a connective tissue layer in the dorsolateral region of the gill chamber. The epithelial cell layer, which separates the thymus from the head-kidney, has no mucuscells. The thymus has no obvious demarcation into an outer cortex and inner cortex. Lymphocytes and the macrophages are dispersed in thethymus parenchyma equably. No Hassall＇s corpuscles are present. Interdigitating cells are observed for the first time and are characteristeristic of their complicated labyrinthine membrane-membrane structure. Meanwhile, the thymus is not always a paired organ and involutes rapidly dur- ing the first 6 months.