Jpn. J. Infect. Dis., 65 (5), 383-391, 2012
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Nilton Akio Muto1, Yuji Sunden2, Tomoe Hattori3,4, Daisuke Fujikura5, Yosuke Nakayama6, Tadaaki Miyazaki6,8, Mitsuo Maruyama7, Takashi Kimura1, and Hirofumi Sawa1,8*
1Division of Molecular Pathobiology, 3Division of Bioresource, and 5Division of Infection and Immunity, Research Center for Zoonosis Control, Hokkaido University, Sapporo 001-0020; 2Laboratory of Comparative Pathology, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818; 4Graduate School of Life Science, Hokkaido University, Sapporo 060-0810; 6Institute for Genetic Medicine, Hokkaido University, Sapporo 060-0815; 7National Center for Geriatrics and Gerontology, Obu-city 474-8511; and 8Global COE Program, Hokkaido University, Research Center for Zoonosis Control, Sapporo 001-0020, Japan
(Received April 25, 2012. Accepted June 6, 2012)
*Corresponding author: Mailing address: Division of Molecular Pathobiology, Research Center for Zoonosis Control, Hokkaido University, N20, W10, Kita-ku, Sapporo 001-0020, Japan. Tel: +81-11-706-5185, Fax: +81-11-706-7370, E-mail: このメールアドレスはスパムボットから保護されています。閲覧するにはJavaScriptを有効にする必要があります。
SUMMARY: This study examined pathological changes in the lung tissues of young and aged mice infected with influenza virus. Young mice inoculated with influenza virus showed body weight loss at 4 days post-infection (dpi), meanwhile body weight decrease started from 9 dpi in the aged mice. We histopathologically examined the lungs of these mice. Immunohistochemical examination revealed that viral antigen-positive bronchiolar and alveolar epithelial cell numbers at 3 dpi were significantly higher in young mice than in the aged ones. Further, viral antigen-positive cells were observed at 9 dpi in the aged mice, but not in the young ones. Diffuse and severe bronchointerstitial pneumonia characterized by the accumulation of polymorphonuclear leukocytes (PMNs) was observed in young mice at 6 dpi. Histopathological changes in the aged mice were milder than those in the young mice. Moreover, T cell and macrophage accumulation in the lungs was significantly higher in the young mice than in the aged mice at 9 dpi. These results suggest that there may be a correlation between the relatively low level of infiltration of PMNs, macrophages, and T lymphocytes and the delayed body weight loss and longer lasting infections observed in the lungs of the aged mice. These findings provide detailed insights into the age-specific course of infection in young and aged populations with associated differences in lung pathology.
