Morphological and cytochemical observations of blood cells of Caiman crocodilus yacare (Daudin, 1802) (Reptilia, Crocodilia)

Abstract

Samples of peripheral blood were collected from 10 healthy Caiman crocodilus yacare and stained with Leishman, for morphological analysis, or submitted to the following cytochemical methods: PAS, Sudan black B, o-toluidine and mercury bromophenol blue. Seven types of cells were identified: erythrocytes, thrombocytes, heterophils, eosinophils, basophils, lymphocytes and azurofilic monocytes. Erythrocytes were elliptical and positive for bromophenol blue. Some mitotic figures were noted. Spindle-shaped thrombocytes showed large nucleus with striking indentation. The cytoplasm was attenuated at one or both poles into knob-like projections containing glycogen. Heterophils revealed round eccentric nuclei and cytoplasm containing glycogen and many polymorphic granules. These granules showed partial positive reaction for Sudan and activity for myeloperoxidase. Eosinophils showed eccentrically located lenticular-shaped nuclei and numerous round granules stained positive with myeloperoxidase and Sudan. Basophils revealed a round central nuclei and cytoplasm with few basophilic round granules. Lymphocytes appeared as polygonal or irregular cells with thin cytoplasm forming bleb-like protrusions. Azurophilic monocytes were round with eccentrically located nuclei and basophilic cytoplasm containing numerous azurophilic granules.