Determination of the Area and Number of Pulmonary Alveoli through the Normal aging Process in CD1 Mouse

The aging process causes anatomical changes in the lungs, as well as a reduction in function. Some pulmonary metrics change depending on the species and strain. The mouse strain CD1 has been widely used to examine multiple aspects of the general aging process. The goal of this study was to determine the area and number of lung alveoli in CD1 mouse as they aged normally. Hematoxylin and eosin-stained paraffin-embedded sections of lungs from CD1 mice aged 2, 6, 12, 18, or 24 months were examined under a light microscope. To measure areas and count alveoli, images were taken with a camera connected to image analysis software. There was a significant difference in the alveolar area among the ages analyzed (F=87.53, Sig.=0.000). The alveolar area of the 6-, 12-, 18-, and 24-month-old mice was significantly greater (all p values < 0.001) than in mice at 2 months of age. Also, the alveolar number was significantly different among the ages tested (F=3.21, Sig.=0.023). When compared to 6-, 12-, and 18-month-old mice, the number of alveoli in 2 month-old mice was larger than in all other age groups, attaining statistical significance (p values of 0.044, 0.014, and 0.002, respectively). As a result of the aging process, we noticed a rise in alveolar area and a decrease in alveolar number. This knowledge could help researchers better understand the pathologic alterations that underpin aged people's susceptibility to chronic lower respiratory tract disorders.