Alvarez F, Villena A, Zapata A, Razquin B
Departamento de Biología Celular y Anatomía, Facultad de Biologiía, Universidad de Leon, Spain.
Vet Immunol Immunopathol. 1995 Jul;47(1-2):163-72. doi: 10.1016/0165-2427(94)05384-5.
A comparative analysis was made of the thymic cytoarchitecture of healthy and Saprolegnia-infected wild brown trout. In Saprolegnia-infected fish, even when the thymus was not invaded by fungal hyphae, the thymic architecture was lost without signs of regionalization. Intercellular oedema, some thymocytes, hypertrophic and degenerated epithelial cells and increased phagocytic activity were also observed. In thymi invaded by the fungus, hyphae occurred isolated or in close apposition to epithelial cells, and the thymic disorganization was more noticeable. Most thymocytes were pyknotic and both epithelial cells and macrophages contained engulfed dead cells. However, no inflammatory response to the fungal invasion was observed. These results confirm the immunodepressed condition of Saprolegnia-infected wild brown trout previously observed in peripheral lymphoid organs. We discuss the secretion of fungal products and/or the high levels of corticosteroids observed in these fish as possible origins of the condition.
对健康的和感染水霉的野生褐鳟的胸腺细胞结构进行了比较分析。在感染水霉的鱼中，即使胸腺未被真菌菌丝侵入，胸腺结构也会丧失且无区域化迹象。还观察到细胞间水肿、一些胸腺细胞、肥大和退化的上皮细胞以及吞噬活性增加。在被真菌侵入的胸腺中，菌丝单独出现或与上皮细胞紧密相邻，胸腺的紊乱更为明显。大多数胸腺细胞呈固缩状，上皮细胞和巨噬细胞都含有吞噬的死细胞。然而，未观察到对真菌侵入的炎症反应。这些结果证实了先前在外周淋巴器官中观察到的感染水霉的野生褐鳟的免疫抑制状态。我们讨论了在这些鱼中观察到的真菌产物分泌和/或高皮质类固醇水平作为这种状态可能的起因。
