牦牛源鲍氏志贺菌人工感染BALB/c小鼠的组织病理学观察

Histopathological Observation in BALB/c Mice Experimentally Infected with Shigella boydii from Yak

为了解牦牛源鲍氏志贺菌对实验动物除肠道外的心、肝等的快速致病性损伤,本研究以牦牛源鲍氏志贺菌感染SPF小鼠,剂量为0.5mL·只-1(2×109 CFU·mL-1),感染后6、18、30、42、54、66h剖杀、取样并对剖解进行详细观察,在每个安排的时间点平行采集3只小鼠的脑、心、肝、脾、肺、肾、小肠、大肠和胰腺等组织,制备组织切片,通过HE染色和免疫组化染色,对感染小鼠的组织病理学变化和细菌定位进行观察,收集小鼠血液进行乳酸脱氢酶、尿素、肌酐、α-淀粉酶、甘油三酯、总蛋白、白蛋白、磷酸激酶、CO2结合力、P、血糖、白细胞数等血液生化指标检测。试验结果表明,小鼠除小肠上皮细胞损伤外,心外膜下出现凝固性坏死病灶,肝组织有炎性细胞浸润及肉芽肿形成,肺泡壁炎性细胞浸润,胰腺上皮细胞肿胀,细胞质溶解,细胞核固缩或碎裂等;心肌细胞、肝细胞、肺泡壁、肾小管细胞、胰岛细胞、肠上皮细胞细胞质内均有待检菌体抗原阳性反应;生化指标除甘油三酯外均有一定变化。试验证实病变的严重程度与菌体抗原检出量成正相关,分离株能在实验动物体内进行大面积侵嗜,心、肝、肺、胰腺、肾也是牦牛源鲍氏志贺菌分离株的主要靶器官。生化指标和病理损伤的特征性变化对该病诊断与研究拓展具有重要价值。

The objective of this study was to research the fast pathogenic damage of Shigella boydii from yak in BALB/c mice organs except intestine.The 4-week-old mouse were given 0.5mL of Shigella boydii isolate（2×10^9 CFU·mL^-1）by gavage.Tissue samples of cerebrum,heart,liver,spleen,lung,kidney,intestine and pancreas were taken from the infected mouse after being infected for 6,18,30,42,54 and 66h,and ever since for every 12 hours to make tissue biopsies,which were then stained with haematoxylin and eosin（H.E）and immunohistochemistry to observe the changes of histopathology and the bacterial antigen localization in experimentally infected ducklings.Mouse serum were collected for biochemical indicators detection including lactate dehydrogenase,urea,creatinine,αamylase,triglyceride,total protein,albumin,phosphokinase,CO2 binding force,P,blood glucose and white blood cell count.The HE staining results showed a series of pathologic changes,not only the pathological damage in intestine epithelial cell as reports inother references,but also coagulation necrosis under the epicardium,cellular infiltration and granuloma in hepatic cells,inflammatory cells infiltrating in alveolar wall,pancreas epithelial cell swelling and cytoplasm dissolving and karyopyknosis or fragmentation.Immunochemistry staining results showed that positive bacterial antigen signals were found in cytoplasm of cardiac muscle cell,hepatocyte,alveolar wall,renal tubular epithelium cell,islet cell and intestinal epithelial cell.Pathological damages,heart and hepatic necrosis of Shigella boydii from yak experimentally infecting mice was first reported in this study.Eleven kinds of blood biochemical indexes of experimental mice changed apparently in each infected time point except triglyceride.This study verified that the severity of the pathology was positively correlated with the Shigella boydii antigen distribution.It was concluded that the isolate was the pantropic bacteria injuring most tissues and cells in mouse,and as well as intestinal,heart,liver,lung,pancreas and kidney were the principal target organs.