小鼠感染猪圆环病毒2型的超微结构病变观察

Ultra-microscopic lesion in mice experimentally inoculated with type 2 of porcine circovirus

为探讨猪圆环病毒2型(PCV2)对小鼠超微结构的病理损伤及其病毒在细胞内的复制,20只6周龄的昆明小鼠随机平均分成2组(即A组和B组),A组小鼠经腹腔注射PCV2细胞培养物0.1mL/只(含病毒1 000TCID50),B组以同样的方式和剂量注射无菌细胞培养液作为对照。于PCV2感染后14d,处死所有小鼠,取其组织做电镜观察和PCV2PCR检测。结果显示,在电镜下,所有PCV2感染鼠的超微结构病变基本一致,主要表现为淋巴器官、心脏、肝脏、肺脏、肾脏、脑、肠等脏器实质细胞凋亡或坏死,细胞内线粒体水肿、内质网扩张,间质毛细血管淤血、炎症细胞浸润,并在脾脏、胸腺、淋巴结的淋巴细、巨噬细胞,以及肝细胞,肾足细胞,脑神经细胞的胞浆或胞核内发现病毒包涵体。同时通过PCR检测,所有PCV2感染鼠的组织均可检出PCV2DNA。B组(对照组)小鼠除在淋巴结可见极少数淋巴细胞凋亡外,其他组织均无任何超微结构病变;同时,所有组织也未检出PCV2DNA。由此说明PCV2可在昆明小鼠多脏器实质细胞内复制,并诱导细胞凋亡。

In order to explore the ultra-microscopic lesions and viral replication in Kunming mice infected with type 2 of porcine circovirus（PCV2）,20 mice random equally divided into 2 groups,namely group A and group B.Mice in group A were injected intraperitoneally with 0.1 mL of viral cell cultures（containing virus 1 000 TCID50） per mouse,and group B were injected with equal volume of cell cultures without virus as same method.Tissues from all euthanatized mice were collected at 14 dpi for preparation of transmission electron microscopy（TEM） and PCR.The results showed that ultra-microscopic lesions in PCV2-infected mice in group A were similar,and characterized by apoptosis or cytonecrosis of parenchymal cells of lymphoid organ,heart,liver,lung,kidney,brain and intestine,and mitochondrion edema,endoplasmic reticulum dilatation within these cells,and capillary congestion,inflammatory cells infiltration in interstitial tissues.Inclusion bodies of PCV2 in lymphocytes and macrophages of lymphoid organ,as well as in hepatocyte,podocyte and neurocyte could be seen,and PCV2 DNA could be determined by PCR in all of tissue of PCV2-infected mice.But not any ultra-microscopic lesion in tissues of 10 sham-infected mice in group B could be seen except lymph node had very small number of lymphocytes apoptosis,and neither PCV2 inclusion body nor PCV2 DNA could be tested out as well.PCV2 can replicate in parenchymal cells of most organs of Kunming mice,and induce cells apoptosis.