A morphometric and morphological study of the lungs of rabbits after unilateral pneumonectomy.

, 406-417. A study was made to determine the changes occurring in the contralateral lung of adult rabbits as a result of left pneumonectomy. Stereological procedures for light microscopy and for electron microscopy were used to quantitate the changes. Lungs from control rabbits, ranging in body weight from 1·0 to 9·0 kg, were also analysed. Resin corrosion casts of left and right lungs were prepared. Left pneumonectomy causes the volume of the right lung to increase to the total paired lung volume in about four weeks. Total surface area, while increasing directly with lung volume in control rabbits, increased as two-thirds of the lung volume after pneumonectomy. In some right lungs there appeared to be an increase in the number of alveoli. Mean linear intercepts for control lungs were fairly constant, but the volume density of alveolar ducts increased with age. In pneumonectomised animals, mean air-space diameter of the right lung increased by about 25% and the volume density of alveolar ducts by 22-33%. The volume density of alveolar wall tissue decreased by about 30%. The average number of alveoli/cm for whole lungs was 2·31±0·46×10, whereas for right lungs eight weeks or more after pneumonectomy it was significantly less (1·70±0·38×10). Morphometry by electron microscopy revealed slight changes in the components of the alveolar septum and a reduction in the thickness of the air-blood barrier. The overall effect of left pneumonectomy was mainly one of a compensatory increase in the volume of the right lung with dilatation of alveoli and of alveolar ducts.