Department of Life Sciences and Biotechnology, University of Ferrara, St. Borsari 46, 44121Ferrara, Italy.
Department of Cellular and Environmental Biology, University of Perugia, St. Elce di sotto 5, 06123Perugia, Italy.
Parasitology. 2021 Apr;148(5):612-622. doi: 10.1017/S0031182021000032. Epub 2021 Jan 13.
The swimbladder functions as a hydrostatic organ in most bony fishes, including the European eel, Anguilla anguilla. Infection by the nematode Anguillicoloides crassus impairs swimbladder function, significantly compromising the success of the eel spawning migration. Swimbladders from 32 yellow eels taken from Lake Trasimeno (Central Italy) were analysed by histopathology- and electron microscopy-based techniques. Sixteen eels (50%) harboured A. crassus in their swimbladders and intensity of infection ranged from 2 to 17 adult nematodes per organ (6.9 ± 1.6, mean ± s.e.). Gross observations of heavily infected swimbladders showed opacity and histological analysis found a papillose aspect to the mucosa and hyperplasia of the lamina propria, muscularis mucosae and submucosa. Inflammation, haemorrhages, dilation of blood vessels and epithelial erosion were common in infected swimbladders. In the epithelium of parasitized swimbladders, many empty spaces and lack of apical junctional complexes were frequent among the gas gland cells. In heavily infected swimbladders, we observed hyperplasia, cellular swelling and abundant vacuolization in the apical portion of the gas gland cells. Numerous mast cells and several macrophage aggregates were noticed in the mucosal layer of infected swimbladders. We found more nervous and endocrine elements immunoreactive to a panel of six rabbit polyclonal antibodies in infected swimbladders compared to uninfected.
大多数硬骨鱼类的鳔具有液压器官的功能，包括欧洲鳗 Anguilla anguilla。鳗线科 Anguillicoloides crassus 的寄生虫感染会损害鳔的功能，严重影响鳗的产卵洄游成功。通过组织病理学和基于电子显微镜的技术分析了来自特拉西梅诺湖（意大利中部）的 32 条黄鳗的鳔。16 条（50%）鳗鱼的鳔中寄生了 A. crassus，每个器官中的感染强度范围为 2 至 17 条成年线虫（6.9 ± 1.6，平均值 ± s.e.）。严重感染的鳔的肉眼观察显示不透明，组织学分析发现黏膜呈乳头状，固有层、黏膜肌层和黏膜下层增生。受感染的鳔中常见炎症、出血、血管扩张和上皮侵蚀。在寄生的鳔上皮中，许多气腺细胞中经常出现空泡和缺乏顶端连接复合体。在严重感染的鳔中，我们观察到气腺细胞的顶端部分增生、细胞肿胀和大量空泡化。在感染的鳔黏膜层中发现了许多肥大细胞和几个巨噬细胞聚集。与未感染的鳔相比，我们在感染的鳔中发现了更多对一组 6 种兔多克隆抗体呈免疫反应的神经和内分泌元件。
