Morphological and cytochemical characterization of thrombocytes and leukocytes in hatchlings of three species of Amazonian freshwater turtles

Abstract

The aim of this paper was to characterize the morphological and cytochemical aspects of thrombocytes and leukocytes in hatchlings of Podocnemis expansa, P. unifilis and P. sextuberculata from the lower Purus River, Amazonas State, Brazil. Blood smears were submitted to staining by Periodic Acid-Schiff (PAS), Peroxidase (PER), Toluidine Blue (TB), Sudan Black B (SBB) and Bromophenol Blue (BB). Only the lymphocytes did not present a positive-PAS reaction, while heterophils of P. unifilis showed a weak positive reaction. Azurophils, heterophils and eosinophils had a weak positive reaction for PER, with the exception of heterophils in P. expansa which stained intensely. Positive staining with BB was observed in granules of heterophils, eosinophils and basophils of P. expansa, P. unifilis and P. sextuberculata, but this was weak in basophils of P. sextuberculata. Sudanophilia was observed in heterophils granules and in eosinophils of P. expansa, P. unifilis and P. sextuberculata. Metachromasia was demonstrated in basophils of these three species. In these turtle hatchlings, heterophils and eosinophils are the most frequent leukocytes and both have a similar role in defense, since the granules of these granulocytes present glycogen, sudanophilia, peroxidase and basic proteins.