Chronic lung inflammation in aging mice.

To determine whether aging is associated with a pro-inflammatory shift in the lung, inflammation and inflammation-related gene expression in the lungs of 12-week-old and 24-month-old Balb/c mice were studied. cDNA microarray and quantitative reverse transcription-polymerase chain reaction analyses showed that eight inflammation-related genes, including CD20, Burkitt lymphoma receptor 1, CXCR-3, provirus integration site for Moloney murine leukemia virus-2, CD72, IL-8RB, C-Fgr, and CD8beta, were upregulated in the aged mice. Immunohistochemistry showed that the lungs of the aged mice contained increased numbers of CD4 cells, CD8 cells, B cells and macrophages. These results suggest that a pro-inflammatory shift occurs in the lungs of mice with aging.