TRYPSIN-INDUCED LEUCOSTASIS - GRANULOCYTE MIGRATION INTO THE TERMINALAIRSPACES

Injection of trypsin triggers the delayed appearance of a lung emphyse ma. Classically, emphysema is attributed to elastase, more particularl y to leucocyte elastase. Indeed the acute phase of this experiment is characterized by a granulocyte sequestration within the lung microvess els in diverse species. We also found granulocytes within the terminal airspaces; this fact implies a granulocyte extravasation and directed migration. In order to evaluate this airspace invading by granulocyte s during trypsin induced-vascular leucostasis, we washed the lung in c ats since this species develop leucocytosis easily. One lobe only was washed for avoiding to harvest the cells present in the trachea and th e main bronchi. This study was designed in several parts: (I) the lung s were washed in normal condition and several months later when trypsi n was given; (2) in a kinetic experiment, 3 lavages were made consecut ively a day either in normal condition or under trypsin treatment; (3) the lung was washed one day after trypsin administration. The granulo cytes, and among them the neutrophils particularly, increased in numbe r or in percentage transiently within the terminal airspaces under try psin treatment; these granulocytes found within the airspaces are abou t 20% of the lung granulocytes.