Abstract
Histological studies were carried out on experimental lung injury in rats. Wistar rats were injected intratracheally with suspension of zymosan, a particulate activator of the alternative complement pathway, and were sacrificed in groups at intervals of : 6 hr, 24 hr, 5 days and 14 days. Histological findings on lungs in the 6-hr after injection group showed polymorphonuclear cell infiltration in the alveolar walls and in the peribronchiolar tissues. In the 24-hr after injection group, the reaction was more marked, and, in the 5-day after injection group, diffuse lymphocytic infiltration, macrophagic accumulation and granuloma-like changes were observed. The response at 14 days was essentially that of 5 days. It was suggested that zymosan-induced lung injury may be activation of alternative complement pathway-dependent and may have some relation to zymosan's particulate nature. Effects of 4 drugs on the zymosan-induced injury at 5 days were investigated. Intra-alveolar lymphocytic infiltration and granuloma-like changes were suppressed by administration of gold sodium thiomalate and Cu-chlorophyllin, but were not suppressed by prednisolone or ketoprofen. Macrophagic accumulation was suppressed by administration of gold sodium thiomalate and prednisolone, but was not by ketoprofen or Cu-chlorophyllin.
