Study of experimental chronic bronchitis in the rat

Abstract

An experimental pattern is discussed, based on the inducement of bronchiectasis in rat, for the study of drugs with action on several pathologic States of the respiratory system. Therefore, the experimental animáis are subjected to an atmosphere contain- ing O2S (300 p.p.m.) for 150 hours (5 hours/day and 6 days/week). For the quantitative determination of the lesión in the anaesthetized animal, a polygraphic recording of expansibility and pulmonary resistance is performed altogether with another parameters representing the respiratory dynamics. Parallelwise, the histopathologic study in trachea is performed, in order to observe the experimented alterations (Hematoxylin Eosine staining) and the location of mucoproteins (P.A.S. staining). The polygraphic recording has revealed the changes that were expected in a pathologic State of this kind, that is to say, a decrease of expansibility and an increase of the pulmonary resistance; both changes have resulted significative in a statistical way. The histopathologic alterations found, confian the changes observed in the mentioned respiratory parameters, that is to say, disapearance of the cilium band, partial atrophy of the tracheal epithelium and cartilage, as well as hyperplasia of the mucosecretor elements.