研究利用免疫组织化学方法对产毒性大肠杆菌（ETEC）感染豚鼠小肠组织中ETEC肠毒素的定位进行了研究。本研究结果表明，发病豚鼠从空肠到回肠明显充血、肿胀，但盲肠、结肠和直肠外观与对照组差别不明显。光镜下见到发病动物肠组织病变主要出现在空肠和回肠，以回肠最为严重。主要病理改变为水肿、炎症细胞浸润和充血。病变部位可以出现在粘膜层、粘膜下层、肌层和浆膜层。取回肠组织切片作免疫组织化学显示ETEC不耐热肠毒素（LT）和耐热肠毒素（ST），可见回肠粘膜表层、粘膜肌层、肌层及浆膜层均呈LT和ST阳性反应，分布弥漫。空白对照和正常豚鼠回肠组织均呈阴性结果。本研究表明，ETEC主要作用于空肠和回肠，尤其是回肠；回肠组织各层都有病变，且与肠毒素的分布一致，证明毒素的作用并不仅限于肠粘膜细胞。%Using immunohistochemical method， distribution of enterotoxins ofenterotoxigenic Escherichia coli( ETEC) in small intestine of the guinea pig infected with ETEC. The results showed t hat the jejunum and ileum of guinea pig infected were obviously hyperemia and ed ema. But no obvious changes were found in the cecum, colon and rectum between i nfecting animals and controls. Under light microscope, pathogenic changes were s een mainly in the jejunum and ileum. The changes mainly were edema, hyperemia an d inflammatory cell infiltration. The sections of ileum were detected by labi le heat enterotoxin(LT) and stable heat enterotoxin(ST) of ETEC. LT and ST were positive on the surface of mucous membrane, muscularis mucosa, tunica muscula ris and fibrosa in infecting guinea pig. The distribution of enterotoxins wer e diffuse and consistent with the histological lesions. No positive reaction was found in normal guinea pig and controls. The present results indicate that the locations of ETEC action were mainly in jejunum and ileum, mostly in the latter. The enterotoxins of ETEC not only act in mucousa of ileum, but other hi stology of ileum were affected.
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