Kinetics of pleural exudation and cellular alterations induced by antigen in actively sensitized rats

ABSTRACT

This study was undertaken to characteize the different phases of the allergic pleurisy induced by ovalbumin in actively sinsitized rats. The reaction was triggered by the intrathoracic injection of ovalbumin (12 microng/cavity) into animals sensitized 14 days before. The challenge caused, at 30 mjin, a drastic mast cell degranulation and exudation which peaked within 4h. At this time, an intense pleural leucocyte recruitment also occurred, accounted for by an increase in the mononuclear cell counts and by a predominant influyx of neutrophils. After 24h, the mast cell counts stated to reover, accompanied by a long-lasting (96 h) accumaltion of pleural eosinophils. Forty-eight hour later, the exudation and neutrophils were at basal levels, whereas mast cell counts increased progressively to reach control values at 120 h. This study describes the time course of the exudatory and cellular alterations observed during pleural inflammation induced by low antigen concentrations