Kinetics of the inflammatory reaction induced by carrageenin in the swimbladder of Oreochromis niloticus (Nile tilapia)

Abstract

The swimbladder, natural cavity of Oreochromis niloticus (Nile tilapia), weighing 100 to 150g, was used to study the carrageenin induced cell kinetics (n=42). Inoculation of 0.1ml of the irritant (0.5%) into the swimbladder determined an inflammatory reaction characterized by local congestion and edema of its wall and cell migration, mainly mononuclear, into the cavity. These phenomena began 3 hours following injection of the irritant and Reached a peak as early as 24 hours. Light and electronic microscopies of the blood cells were undertaken to characterize the inflammatory cells that might migrate to the swimbladder. Thrombocytes, predominantly, migrated into the cavity, at different time intervals, after the inoculation of the irritant. Few macrophages, lymphocytes, granulocytes and other morphofunctionally undefined cells also took part in the exudate composition.