Vaccine-associated granulomatous inflammation and melanin accumulation in Atlantic salmon, Salmo salar L., white muscle

The purpose of this study was to investigate the nature of variably sized pigmented foci encountered in fillets of farmed Atlantic salmon, Salmo salar L. The material was sampled on the fillet production line and on salmon farms from fish with an average size of 3 kg from various producers. The fish had been routinely vaccinated by injection. Gross pathology, histology, immunohistochemistry using antisera against major histocompatibility complex (MHC) class II beta chain and transmission electron microscopy (TEM) were used to characterize the changes. Macroscopically, melanized foci were seen penetrating from the peritoneum deep into the abdominal wall, sometimes right through to the skin, and also embedded in the caudal musculature. Histological investigation revealed muscle degeneration and necrosis, fibrosis and granulomatous inflammation containing varying numbers of melano-macrophages. Vacuoles, either empty or containing heterogeneous material, were frequently seen. The presence of abundant MHC class II+ cells indicated an active inflammatory condition. TEM showed large extracellular vacuoles and leucocytes containing homogeneous material of lipid-like appearance. The results showed that the melanized foci in Atlantic salmon fillet resulted from an inflammatory condition probably induced by vaccination. The described condition is not known in wild salmon and in farmed salmon where injection vaccination is not applied.     

人工养殖圆口铜鱼头肾组织学特征及操作胁迫对其影响

采用石蜡切片和组织涂片技术,对人工养殖圆口铜鱼(Coreius guichenoti)在正常和操作胁迫下头肾的组织、细胞形态结构及细胞数目进行研究,并探讨了其在操作胁迫后0.1、4、24 h 的变化特征.石蜡切片观察发现,圆口铜鱼头肾实质中无肾单位,主要由淋巴组织、造血组织、血管、肾间组织及黑色素巨噬细胞组成.各组织及细胞结构形态正常,分布规则.在操作胁迫后0.1、4 h 时,头肾中黑色素巨噬细胞数量较正常组显著增多,形成黑色素巨噬细胞中心,同时肾间组织增生,肾间细胞面积、核面积和核直径均有不同程度增大;在操作胁迫后24 h 时,黑色素巨噬细胞数量和肾间细胞面积、核面积、核直径均减小,并均低于正常组.组织涂片观察发现,正常圆口铜鱼头肾中主要有6类细胞:红细胞、淋巴细胞、单核细胞、嗜中性粒细胞、嗜碱性粒细胞、血栓细胞.应激后不规则红细胞增多,红细胞、嗜中性粒细胞数量和嗜碱性粒细胞持续减少;淋巴细胞和单核细胞数量在应激后0.1 h短暂增多,随后持续降低;血栓细胞数量持续增加.研究表明,圆口铜鱼头肾组织和细胞在应激后较短时间(0.1、4 h)内发生显著变化,部分组织的生物功能在24 h 时逐渐恢复正常.本研究可为圆口铜鱼及其他硬骨鱼类头肾的组织学研究、养殖与驯化过程中的健康监测等方面提供参考依据.     

Melano-macrophage centres and their role in fish pathology

Melano-macrophage centres, also known as macrophage aggregates, are distinctive groupings of pigment-containing cells within the tissues of heterothermic vertebrates. In fish they are normally located in the stroma of the haemopoietic tissue of the spleen and the kidney, although in amphibians and reptiles, and some fish, they are also found in the liver. They may also develop in association with chronic inflammatory lesions elsewhere in the body and during ovarian atresia. In higher teleosts, they often exist as complex discrete centres, containing lymphocytes and macrophages, and may be primitive analogues of the germinal centres of lymph nodes. Melano-macrophage centres usually contain a variety of pigments, including melanins, and these increase in range and volume in older fish or in the presence of cachectic disease. Melano-macrophage centres act as focal depositories for resistant intracellular bacteria, from which chronic infections may develop. Iron capture and storage in haemolytic diseases appears to be a primary function, but antigen trapping and presentation to lymphocytes, sequestration of products of cellular degradation and potentially toxic tissue materials, such as melanins, free radicals and catabolic breakdown products are among other functions that have been ascribed. Recent work suggests that they are a site of primary melanogenesis rather than mere storage. Melano-macrophage centres increase in size or frequency in conditions of environmental stress and have been suggested as reliable biomarkers for water quality in terms of both deoxygenation and iatragenic chemical pollution.     

欧鳗脾和肾中黑色素巨噬细胞中心的形态学与细胞化学研究

应用组织化学与电镜技术对欧鳗脾脏和肾脏中黑色素巨噬细胞中心(MMCs)进行研究。结果表明:脾脏和肾脏中均存在MMCs,它们呈圆形、卵圆形或不规则形状;脾脏MMCs有邻血管分布的特点,而肾脏MMCs的分布无此特点;脾脏和肾脏中的MMCs均含有铁血黄素、黑色素及脂褐质3种色素,但脾脏MMCs以铁血黄素为主,肾脏以黑色素和脂褐质为主;脾脏MMCs中存在色素颗粒和细胞碎片。初步推测,欧鳗脾脏MMCs与肾脏MMCs的功能有可能是不相同的。     

棘胸蛙脾脏的进化水平分析与血脾屏障的组成及功能

为明确棘胸蛙脾脏的进化水平及血脾屏障的组成与功能,采用组织学与电镜技术,酸性α-乙酸萘酚酯酶、酸性磷酸酶及碱性磷酸酶染色,并结合活体注射台盼蓝染液对棘胸蛙脾脏进行了研究。结果显示,棘胸蛙脾脏出现了红髓与白髓的分化,但边界不清,无边缘区结构,未形成动脉周围淋巴鞘与生发中心;椭球体少量分布于红髓与白髓的边界区,未形成椭球周围淋巴鞘。由黑色素巨噬细胞聚集而成的黑色素巨噬细胞中心分散在白髓内部,或包裹于白髓四周。脾脏内细胞对酸性α-乙酸萘酚酯酶染色呈阴性。超微结构观察与台盼蓝活体染色实验结果显示,棘胸蛙的血脾屏障由脾索中的网状细胞及游离的巨噬细胞组成,吞噬过程中酸性磷酸酶呈现出规律性的变化。研究表明,棘胸蛙脾脏的进化处于中等水平,脾脏内已具备血脾屏障结构保障着白髓内环境的稳定。实验结果完善了棘胸蛙脾脏结构与功能的相关研究资料,为深入探索无尾类两栖动物的免疫应答机制提供了依据。