CONICET | Buscador de Institutos y Recursos Humanos

The aim of the present study was to characterize the gills of juvenile of Odontesthes bonariensis structurally and histochemically. The gills of 50 fishes were dissected out, fixed in 10% formaldehyde solution and embedded in paraffin wax. Sections of 2 μm were stained with haematoxylin-eosin, P.A.S., alcian blue (pH 2,5), acid orcein-Giemsa and Jones methenamine. Branchial filament stroma was composed of hyaline cartilage surrounded by a dense connective tissue with prevalence of collagen and reticular fibres. Over this a plane stratified epithelium resting on a thick basal membrane rich in reticular fibres was observed. Chloride cells (CC), rodlet cells (RC) and mucous cells were observed in this epithelium. The latter cells were located in the most superficial strata, presenting a basal euchromatin nucleus and apical vesicles containing acid mucins. CC were located in the interlamellar space in 2-3 cell clusters. They showed a polygonal shape, presenting a round euchromatin nucleus and abundant weakly basophile cytoplasm. RC revealed an outlying nucleus and abundant P.A.S. positive cytoplasmic granules. The lamellae stroma was poorly developed, represented by scarce collagens and elastic fibres surrounding capillaries distributed parallel to the lamellae base. Those vascular spaces were defined by lateral pillar cell projections. These cells showed a small heterochromatin nucleus that occupied most of the basophile cytoplasm. Both sides of the capillaries were covered by a simple flat epithelium that would improve the efficiency of gas diffusion through the water-blood barrier. The biochemical composition and general structure of gill tissues in this species are similar to those described for other teleosts and mainly for fresh water fishes.

enviar mensaje