Dynamics of Leucocytic Inflammatory Responses in Carp

Abstract

Sequential changes of leucocytes infiltration were studied quantitatively in orbital inflammation of carp caused by injection of 30% gum arabic solution (0.25ml/each orbit). Inflammatory exudates together with orbital tissues were collected and treated with 5 mg of collagenase (125-200 U/mg) to prepare leucocytes suspension. The volume of the suspension was made up for 1ml by adding Hanks solution, then the total number of leucocytes was counted with a hemocytometer. Number of each type of leucocyte was calculated as the product of percentage of the leucocyte type on a smear and the total number. Differential leucocytes counts in the peripheral blood were estimated on the smear preparations. From stamp preparation of head-kidney, ratio of three maturational stage of neutrophils i.e. mature, immature type I and type II was also estimated. The latter two may be comparable with myelocytes and promyelocytes.
Infiltration of neutrophils into the orbital tissue occurred rapidly within one day after the injection of the gum arabic. In advance of the migration, neutrophils showed acute increase in the peripheral blood and decrease in the head kidney. These results indicate that neutrophils stored generally in the head kidney are released to the peripheral blood before the migration to the inflamed lesion. Migrations of monocytes, basophils and lymphocytes were not so active as neutrophils and reached a maximum in about 4 to 6 days. Together with them, blood monocytes and basophils showed some increase, although blood lymphocytes decreased markedly in 6 hours.