P426

HERGET, J., R. HOLUŠA, F. PALEČEK (Dept. Pathol. Physiol., Fac. Paediat., Charles Univ,. Inst. Hyg. Epidemiol., Prague). Development of Experimental Pulmonary Hypertension. Physiol. bohemoslov., 23(6): 527--537, 1974.

A model lung disease characterized by pulmonary hypertension and later also by pulmonary emphysema was induced in 30-day-old male rats by tracheoconstriction and the repeated instillation of aqueous bean (Phaseolus vulg.) extract. At the age of 60 and 150 days, tidal volume, rate of breathing, the lung compliance and resistance and functional residual lung capacity were determined in a body plethysmograph. The pulmonary artery was then catheterized in closed chest rats and, after determining the b1ood pressure in the right ventricle, the maximal, minimal and mean blood pressure in the pulmonary artery were measured. The left and right ventricle and the interventricular septum were weighed and the right-left heart index was calculated. The lungs were treated histologically and were evaluated both quantitatively and qualitatively. The pulmonary blood vessel morphology was evaluated separately.

Thirty days after beginning of the experiment, pulmonary hypertension characterized by an increase in the mean blood pressure in the pulmonary artery from 16±1 torr (mean ± S.E.) in the controls to 24±1 torr was found in all the experimental animals. No further progression of pulmonary hypertension occurred and after 120 days the mean blood pressure in the pulmonary artery was 16±0.8 torr in the controls and 26±2 torr in the experimental animals. On the 30th day the functional residual lung capacity was increased, while only dilatation of the alveolar ducts was found morphologically. Functional and morphological signs of vesicular pulmonary emphysema were not found until the 120th day of the experiment. Functional changes in lung circulation were not accompanied by morphological changes in the pulmonary blood vessels during the given observation period.