[The mechanism of age-related change in lung elastic recoil pressure].
To investigate the mechanism of age-related change in lung elastic recoil, golden syrian hamsters were divided into three age groups (11-wk group, n = 20; 24-wk group, n = 25; 60-wk group, n = 15). Pressure-volume curves in isolated lungs, length-tension properties of alveolar wall, surface tensions by modified Wilhelmy balance, and collagen and elastin concentrations in the lung tissue were measured. Light and electron micrographs and morphometry were studied. Age-related change was not observed in lung elastic recoil in hamsters. However, old hamsters significantly increased a mean linear intercept and the elasticity constant of alveolar wall. On one hand, a surface tension was increased in old hamsters, associating with the decrease in the number of lamellar body of alveolar type 2 cells. These findings suggested that the reduction in lung elastic recoil which should be caused by both the increase in air space and the decrease in extensibility of alveolar wall would be compensated by the increase in surface tension in old hamsters, which may account for the no age-related change in elastic recoil in hamster lungs.
Kato
S
S
First Department of Internal Medicine, Yamagata University School of Medicine, Japan.
Takahashi
K
K
D000375:Aging / Q000502:physiology*; D000818:Animals; D003094:Collagen / Q000378:metabolism; D006224:Cricetinae; D004548:Elasticity; D004549:Elastin / Q000378:metabolism; D066298:In Vitro Techniques; D008168:Lung / Q000378:metabolism / Q000502:physiology*; D008647:Mesocricetus; D011650:Pulmonary Alveoli / Q000502:physiology; D013500:Surface Tension
D003094:Collagen; D004549:Elastin