Morphological investigation of respiratory tract in rats affected by nitrogen dioxide

Abstract

The study was performed in 120 Wistar male rats. Animals were exposed to nitrogen dioxide for 15, 30, 60 or 90 days. Ten intact rats were as controls for each exposed group. Histological examination was performed using immunohistochemistry and morphometry. Pathological changes developed simultaneously in all lung structures. After 15-day exposition with nitrogen dioxide, acute changes have been observed, such as oedema, mucosal thickening and inflammation, enhanced bronchial secretion. In 30 days, morphological features reflected a subacute stage. In 60 days of exposition, inflammation became chronic with sclerosis of bronchial wall followed by worsening of the pathology and occurrence of panacinar emphysema if exposition was prolonged to 90 days.