[Early changes of postpneumonectomy lung growth in premature rats].
Following pneumonectomy in animals, the contralateral lung increases in volume, weight, collagen content, protein, and cell number, reaching levels approximate to those of both lungs of control animals. The volume and weight response in quicker and more complete in young animals compared to old animals. The increase in the amount of DNA was found to be greater in young rats compared to old ones. However, little is known about the effects of pneumonectomy in immature animals, in which combined effects of normal and the compensatory lung growth may be expected. The present studies were aimed at elucidating early changes in terms of morphology and biochemistry in the contralateral lung following pneumonectomy in premature rats. Male Sprague-Dawley rats (2 week-old) were subdivided into 3 groups. Group P, underwent left pneumonectomy, group S was sham operated, which group C was matched by age, sex, and weight with group P. Morphological studies consisted of light microscopic morphometry and immunohistochemistry using anti-bromodeoxyuridine (BrdU) were performed. Biochemical studies included measurement of DNA polymerase activity, DNA and RNA content, collagen and elastin content. The wet lung weight in group P after one week reached approximately the same as that of bilateral lungs of groups S and C. The fixed lung volume of group P reached that of group S or group C at three weeks. The activity of DNA polymerase and BrdU positive alveoli were increased only during the early period following pneumonectomy. DNA content in group P reached the same range as group S and C at 4 weeks, suggesting the occurrence of cellular hyperplasia.(ABSTRACT TRUNCATED AT 250 WORDS)
Mizuuchi
T
T
Pulmonary Division, Tokyo Metropolitan Geriatric Hospital, Japan.
Kida
K
K
Taguchi
T
T
Seyama
Y
Y
D000818:Animals; D003094:Collagen / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism; D004549:Elastin / Q000378:metabolism; D008168:Lung / Q000254:growth & development* / Q000378:metabolism / Q000502:physiology; D008297:Male; D011013:Pneumonectomy; D012313:RNA / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
D012313:RNA; D003094:Collagen; D004247:DNA; D004549:Elastin; D004259:DNA-Directed DNA Polymerase