AGE-RELATED-CHANGES IN THE STATIC AND DYNAMIC-MECHANICAL PROPERTIES OF MOUSE LUNGS

To investigate the effects of aging on pulmonary mechanical properties in mice, we devised a new experimental apparatus to measure the respi ratory impedance of excised lungs in mice and examined age-related cha nges in both static and dynamic properties. In an accelerated senescen ce-resistant strain of mice, SAMR1 (Takeda, T., Y. Fukuchi, Y. Uejima, K. Teramoto, T. Oka and H. Orino, J. Am. Geriatr. Sec. 39: 911-919, 1 991), ranging from 3 to 24 months of age, static compliance (Cst) as w ell. as total lung capacity increased significantly with age, whereas specific compliance and the K value, as determined by exponential anal ysis, showed no significant change. In the dynamic study, dynamic comp liance (Cdyn) increased significantly with age, whereas the frequency dependence of Cdyn (Cdyn/Cst) did not vary with age. From these result s we concluded that lung elasticity, normalized to lung volume, remain ed constant with age and that the effects of aging on pulmonary mechan ics might be solely derived from increases in lung volume in the SAMR1 strain of mice.