Rat pleurisy induced by kaolin or croton oil: time course of fluid accumulation and white cell migration.

Rat pleurisy was induced by intrapleural injection of 0.1 ml of 1% kaolin or 1% croton oil, and the time courses of pleural fluid accumulation and white cell migration were examined. Peak pleural fluid accumulation was observed at respectively 5 and 16 h after the inciter injection. Migration of white cells into the pleural cavity showed a peak at respectively 7 or 24 h after each inciter. Polymorphonuclear leukocytes were predominant in pleural cells of kaolin pleurisy at 3 h, while in croton-oil pleurisy the major white cells were mononuclear cells and lymphocytes at 3 h, and polymorphonuclear leukocytes appeared later around 16 h. Pretreatment with several agents modified both types of induced pleurisy. Kaolin pleurisy at 3 h was suppressed by indomethacin, mefenamic acid, paramethasone, bromelain and soy-bean trypsin inhibitor, while croton oil pleurisy at 3 h was suppressed significantly by indomethacin and paramethasone.