Paraquat에 의한 백서폐의 급성기변화에 대한 연구: 기관지폐포세정액분석과 페포염의 초미세 형태학적 소견

Abstract

This study was carried out to investigate the intricate mechanisms of alveolitis of rat lungs treated with paraquat. Thirty-nine male Sprague-Dawley rats, maintained on a stock diet, weighing 200gm, average vere divided into 3 experimental groups. Group 1. Control group. Ten rats. Intraperitoneal injections of 2ㅡ4 ml normal saline only. Group w. Thirteen rats. Ten, 20, 25, 30, and 40 mg per kg of body weight was administered intraperitoneally. Animal were sacrificed 5 hours, 1, and 2 days after paraquat treatment. Group 3. Sixteen rats. Twenty, 25,30, and 40mg per kg of body weight was administered to the animal died 2ㅡ5 days after paraquat administration. Sacrificed animal lungs were examined gross, light microscopic, ultrastructural observation, along with cellular analysis of sequential bronchoalveolar lavage fluid. The results were as follows: Light microscopically, the salient features found of acute stage lungs were alvcolitis. Earliest forms of intraalveolar bud were occasionally seen. The spontaneously dead rats showed marked congestion and hyaline membrane formations along the alveolar walls. Electron microscopically, the acute stage lung revealed many neutrphils and macrophages in the alveolar spaces and wall. Foci of earliest intraalveolar bud formation were also evident, along with macrophages passing through the defect of alveolar wall. Cellular analysis of bronchoalveolar fluid lavage in acute stage lungs revealed marked increase of neutrophils, leading to the increase in the total absolute cell counts. It can be concluded, therefore: That alveolitis of the paraquat-treated lungs of the rat is probably mediated by intraalveolar migrations of the alveolar macrophages through the defects created in the epithelial lining surface to its basement membrane, which were inflicted upon the alveolar wall by the paraquat toxicity. Activated macrophages may be responsible for the migration of neutrophils into the alveolar spaces to form the neutrphilic alveolitis. Activated neutrophils may be responsible for injury to the lung parenchyma, leading to spontaneous death of rats.