Respiratory mechanics in the aging rat.
1. Mechanical behavior of the respiratory system and pulmonary histopathology were investigated in young (8 months) and old (18 months) adult Wistar rats. 2. Respiratory mechanics were studied under static conditions and during both relaxed and forced expiration. Morphological studies consisted of descriptive light microscopy analysis of intratracheally-fixed, paraffin-embedded pulmonary tissue. 3. Old animals exhibited morphological emphysema and chronic bronchitis, decreased respiratory system (2.40 vs 3.42 cm H2O/ml) and lung (1.32 vs 2.30 cm H2O/ml) elastances, forced vital capacity (13.00 vs 14.32 ml), forced expiratory mean flows between 50 and 75% (35.67 vs 60.50 ml/s) and 75 and 100% (6.67 vs 17.67 ml/s) of forced vital capacity, and an increased respiratory system time constant (0.114 vs 0.082 s) in relation to young rats. 4. These results indicate that old animals suffer from a chronic obstructive pulmonary disease that resembles human pulmonary emphysema.
Saldiva
P H
PH
Laboratório de Poluição Atmosférica Experimental and Instituto do Coração, Faculdade de Medicina, Universidade de São Paulo, Brasil.
Caldeira
M P
MP
Zin
W A
WA
D000375:Aging / Q000502:physiology*; D000818:Animals; D005540:Forced Expiratory Flow Rates; D005541:Forced Expiratory Volume; D008171:Lung Diseases / Q000503:physiopathology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012143:Respiratory Physiological Phenomena