Studies on acute inflammation in the chicken using mesentery as a test system.

An acute inflammatory response was produced in the chicken by the intraperitoneal injection of turpentine and vascular permeability was assessed by the technique of carbon labelling. This revealed a biphasic pattern of increased permeability which comprised an immediate transient reaction and a delayed more prolonged response. In both phases, the increased permeability remained confined to venules only. The vascular permeability was dissociated in time from leucocyte emigration. The pattern of leucocyte emigration revealed that heterophils and monocytes emigrated concurrently. Participation of basophils in significant numbers in the early stages indicated their possible role in avian inflammation. Examination of mast cells revealed morphological changes of degranulation and disruption. There was a coincident reduction in the population of these cells. It was thought likely that vasoactive amines released from the degranulated mast cells and the basophils might initiate the early vascular changes by acting on the venules.