Yamada M, Narita M, Nakamura K, Tsuboi T, Kawashima K
National Institute of Animal Health, Kannondai, Tsukuba, Ibaraki, 305-0856, Japan.
J Comp Pathol. 2003 Feb-Apr;128(2-3):140-5. doi: 10.1053/jcpa.2002.0618.
Three calves aged 1 week (group 1), three aged 6 weeks (group 2) and three aged 6 weeks (having been pretreated with dexamethasone) (group 3) were infected endobronchially with bovine adenovirus type 3 (BAV-3). All calves had received colostrum. The histopathological, immunohistochemical, ultrastructural and TUNEL features were examined on post-inoculation day (PID) 3, 5 and 7. Viral replication and intranuclear inclusions were frequently observed in groups 1 and 3, but not in group 2. The lesions became progressively severe on PID 5 and 7 in group 1. In group 3, however, the cellular injury caused by BAV-3 was of short duration and the lesions began to resolve at PID 7. Numerous apoptotic cells were seen in the PID 3 calves of all three groups, and in the PID 7 calves of groups 2 and 3; however, the PID 5 and 7 calves of group 1 showed only a few apoptotic cells in the alveolar septa. The results indicated that (1) the durability of BAV-3 infection in the lung was closely related to apoptosis, and (2) the host defence mechanism that induced apoptosis in infected cells was age-related.
选取3头1周龄的犊牛（第1组）、3头6周龄的犊牛（第2组）以及3头6周龄且已用 dexamethasone 预处理过的犊牛（第3组），通过支气管内接种3型牛腺病毒（BAV - 3）进行感染。所有犊牛均已摄入初乳。在接种后第3天、第5天和第7天检查组织病理学、免疫组织化学、超微结构和TUNEL特征。在第1组和第3组中经常观察到病毒复制和核内包涵体，但在第2组中未观察到。在第1组中，接种后第5天和第7天病变逐渐加重。然而，在第3组中，BAV - 3引起的细胞损伤持续时间较短，病变在接种后第7天开始消退。在所有三组接种后第3天的犊牛以及第2组和第3组接种后第7天的犊牛中均可见大量凋亡细胞；然而，第1组接种后第5天和第7天的犊牛在肺泡间隔中仅显示少数凋亡细胞。结果表明：（1）BAV - 3在肺内感染的持续时间与细胞凋亡密切相关；（2）诱导受感染细胞凋亡的宿主防御机制与年龄有关。
