Studies on the cellular response in avian inflammation using a simple subcutaneous pouch model.

A subcutaneous pouch model was developed and used for examination of cellular events in the local acute inflammatory response in the chicken. The model involved insertion of a pair of coverslips-dipped in the irritant-into the prepared subcutaneous pouch, and their replacement with plain coverslips at frequent intervals. The model was simple to operate, caused minimal distress to the experimental bird, and permitted multiple continual sampling of emigrating cells. The cytological features and migratory sequence of inflammatory cells produced by non-immunological and immunological stimuli were studied over a period of 48 h. The initial migration of leukocytes comprised heterophils and monocytes. This was soon followed by emigration of basophils. The basophilic reaction was pronounced in response to Escherichia coli endotoxin. Lymphocytes were prominent in the later stages. Also, in the later stages the monocytes apparently coalesced, formed syncytia and even what appeared to be distinct multinucleated giant cells. The results obtained by the present model corroborated the findings of earlier investigators recorded through the use of tissue sections and impression smears. It is suggested that the subcutaneous pouch model may offer an excellent system in avian inflammation research.