Histological and histochemical study of Spleen in Argyrosomus hololepidotus

Argyrosomidae family and the species Argyrosomus hololepidotus due to having high protein levels, are among the most valuable aquatics in the Persian Gulf, Oman Sea and the coasts of Khuzestan. Lymphoid tissues are of the most important tissues in fish which their evaluation is important in health and disease investigation. Unlike mammals, fish lack lymph nodes and also there is not hematopoietic tissue in their bone marrows, so hematopoiesis is done in their spleen and kidney. In this study, 6 Argyrosomus hololepidotus were provided from the Persian Gulf. Tissue samples from the spleen with 5mm thickness were prepared and fixed in 10% buffered formalin. Then tissue sections were prepared in 5-6 μ and after H&E staining, the structures of the capsule and parenchyma of spleen were studied histologically. In order to confirm the results and findings of this staining, some other specific stainings such as PAS, Masson trichrome and silver staining were used. Microscopic results showed that tissue structure of spleen parenchyma was consisted of white pulp, red pulp, melano-macrophage centers and ellipsoid capillaries. Much of the red pulp is occupied by sinusoidal capillaries full of erythrocyte, which indicates the spleen in Argyrosomus hololepidotus serves as a source of blood reservoir.