Immunohistochemistry distribution and pathological characteristics of Aeromonas hydrophila in several organs of European eel（Anguilla anguilla） after artificial infection | 嗜水气单胞菌在欧洲鳗鲡体内的免疫组织化学定位与病理观察

Chinese. 摘　　要：采用从鳗鲡分离的嗜水气单胞菌进行人工感染试验,以探讨感染后不同时期嗜水气单胞菌在欧洲鳗鲡肝脏、肾脏和肠道内的定位和由此引起的组织病理学变化。将细菌分2次对鳗鲡进行肌肉注射。第1次采用每克体质量10. -10. cfu的不同剂量注射以确定该菌的半数致死量,结果表明其半数致死量为5×10. cfu/g。第2次以每尾鱼1×10. cfu的剂量注射欧洲鳗鲡,此后分别在注射后6、24、48 h采集鳗鲡的肝脏、肾脏、肠道进行组织病理学和免疫组织化学定位研究。结果表明：3个时期的临床症状和病理变化存在一定的差别,鳗鲡早期无明显病理变化,而后期主要表现为败血症症状;鳗鲡肾脏组织的病理变化较其他脏器明显,主要表现为肾小管上皮细胞肿胀和肾小球坏死脱落;鳗鲡肝脏则主要表现为严重充血,肠道偶见肠粘膜脱落。免疫组织化学定位结果表明,感染细菌主要分布在鳗鲡肾脏内,肝脏和肠道也有感染细菌分布。

English. Eels were experimentally infected with Aeromonas hydrophila which was isolated from European eel（Anguilla anguilla） in order to evaluate the pathological changes and distribution of the bacteria in the organs at different time after the infection.First,we injected Aeromonas hydrophila into the eel muscle in five doses to determine the LD50 of this bacteria.The result showed the LD50 was 5×104 cfu/g of the eel＇s body weight.Then eels were injected the bacteria in the dose of 1×107 cfu per fish into the eel muscle.We collected liver,kidney and intestine of the moribund eels at 6,24 and 48 h after the injection,and we studied the pathological symptoms and immunohistochemistry distribution of the bacteria.The result indicated that clinical signs and pathological findings were in accordance with the blood poisoning of eels.Kidney showed more pronounced lesions including necrosis in sinusoids and peritubular capillaries in the kidney compared with the other organs.Liver lesions were hyperaemia,and abiogenetic desquamation of the plasma was in intestine.The most primary distribution of the bacteria in internal organs was kidney.The challenged bacteria were also found in liver and intestine of the eels.