Morphological and enzymecytochemical study of leucocytes in juveniles of Argentinian silverside (Odontesthes bonariensis)

VIGLIANO, F.A.; BERMÚDEZ, R.; QUIROGA, M.I.; NIETO, J.M.

Foz do Iguaçu, Brasil/Puerto Iguazú, Argentina

Congreso; XV Pan American Congress of Anatomy; 2004

Pan American Association of Anatomy

The structure and function of leucocytes vary widely between fish species. Due to the importance of their knowledge to understand the morphology of haema-lymphopoietic organs and immune response, the aim of this study was to characterize the structure and enzyme activity of blood leucocytes from juveniles of Argentinian silverside (Odontesthes bonariensis). Ten healthy fish were used. After sacrifice blood was withdrawn by section of caudal peduncle. Blood smears were stained with panoptic dye and enzymecytochemical assays for peroxidase (PX) and acid phosphatase (ACP) were performed. Four mature cell types were observed: lymphocytes, granulocytes, monocytes and thrombocytes. Lymphocytes were small and rounded. They showed a high nucleus-cytoplasm ratio and an irregular outline due to the presence of superficial projections. Granulocytes were larger than lymphocytes with a euchromatic, pleomorfic, and peripherally located nucleus. Their cytoplasm was weakly basophilic with a large amount of PX and ACP-positive granules. Monocytes were the largest cell, with a euchromatic and oval to kidney-shaped nucleus and a basophile cytoplasm with light vacuoles. Thrombocytes showed a long shape and a large heterochromatic nucleus. Inside their acidophile cytoplasm small ACP-positive granules were seen. The present study allowed to know the morphology of blood leucocytes of the Argentinian silverside. The presence of granules positives to the enzymecytochemical techniques employed suggests a possible phagocytic function in granulocytes and thrombocytes in this specie.