Haematology of swordtail, Xiphophorus helleri. III. Ultrastructural characterization and peroxidase activity localization of blood cells in kidney and spleen of Xiphophorus helleri

The morphology of blood cells in the kidney and spleen of Xiphophorus helle ri was characterized by electron microscopy. Erythrocytes, thrombocytes, ly mphocytes, granulocytes and monocytes/macrophages were identified. Thromboc ytes were elongate and contained bundles of microtubules and a canalicular system. Lymphocytes were heterogeneous in morphology. Granulocytes were div ided into two types, based on the light microscopic results, which were ext ended by the present electron microscopic study. Neutrophils and eosinophil s differed in abundance, cell shape, morphology of the nucleus and granula. Neutrophils displayed a spherical to three-lobulated nucleus and different types of granula. Several intermediate forms of granula were observed. The complement of granules displayed a different composition in the cells. The se findings suggest a maturation process of a single type of granulum rathe r than several types. Eosinophils also contain different types of granula, described as G1-G4. The cell shape was variable and nuclei were small and e ccentric. Monocytes and macrophages frequently showed autophagocytotic figu res. A peroxidase reaction was observed only in the granula of neutrophils.