PRRSV感染致断奶仔猪肺脏和外周免疫器官的病理损伤

Histopothological study on progressive injury of lung and peripheral immune organs of weaned piglets infected with PRRSV

用PRRSV ATCC VR-2332株感染8头28日龄仔猪,同时设立2头健康对照猪。PRRSV单独感染猪分别于感染后7,17,25 d各剖杀2,3,3头,对照组于17,25d各剖杀1头。剖杀后采集脾脏、肺脏和全身主要淋巴结(颌下淋巴结、肺门淋巴结、腹股沟淋巴结和肠系膜淋巴结)等免疫器官,用甲醛溶液固定,组织石蜡切片以观察显微病理变化。试验组猪的抗体和抗原检测结果均表明,感染后7 d血清PRRSV抗体和免疫器官组织PRRSV抗原部分呈阳性;剖检和石蜡切片结果均显示,试验猪于攻毒后,随着病程的发展,发生了不同程度的间质性肺炎及相应的显微病变,PRRSV单独感染能引起免疫器官以淋巴细胞及巨噬细胞变性坏死为特征的急性炎症变化,造成免疫损伤,进而引起免疫抑制。

Using the PRRSV ATCC VR-2332 strain to infect with eight 28-day-old piglets,and two healthy piglets as control.Two,three and three piglets monoinfected by PRRSV were killed on the 7th day,17th day and 25th day after infectionon respectively,while the uninfected two piglets were killed on the 17th day and 25th day,respectively.Then collected the spleen,lung and the main peripheral lymphoid nodes of the test piglets,including submandibular lymph nodes,hilar lymph nodes,inguinal lymph nodes and mesenteric lymph nodes,fixed with formaldehyde to make paraffin sections observed microscopic pathological changes.Detecting PRRSV antibody and antigen of experimental group revealed that serum PRRSV antibody and antigen in part of immune tissues were positive on the 7th day,indicating that the artificial infection with PRRSV was successful.With the development of the disease,necropsy findings and dynamic histopathological changes showed that different degrees of interstitial pneumonia and the corresponding micro-lesions occurred in the piglets of post-infection,and monoinfection caused by PRRSV could give rise to acute inflammation of immune organs,which was characterized by degeneration and necrosis of lymphocyte and macrophage and could induce immun injury and immunosuppression.