Document Type : Original Article
MARINE BIOLOGY DEPARTMENT, FACULTY OF NATURAL RESOURCES AND MARINE SCIENCE OF INTERNATIONAL CAMPUS OF TARBIAT MODARES UNIVERSITY, NOOR, IRAN
Objective: cortisol is the major corticosteroid in fish osmoregulation and Persian sturgeon is one of the endangered and economical species of the Caspian Sea sturgeons; this study is one of the first to investigate the effects of cortisol on one species of the Acipenserids species.
Materials and Methods: Samples were fixed in Bouin’s solution dehydrated embedded with paraplast and subsequently sectioned. Immunohistochemical studies were performed by using IgGα5 and flourescin isothiocyanate conjugated (FITC) antibodies through fluorescence light microscopy. Measurements of the chloride cells were examined by Image Tools (2.0) image analysis software.
Results: In the cortisol treatment there were 492 chloride cells per mm2 of the gill epithelium which was significantly (p = 0.01) higher than the control group (289 chloride cells). The lengths of chloride cells were 13.9325 ± 0.5 μm and 16.0935 ± 0.5 μm in the cortisol and control groups respectively; as reported the length was significantly smaller in the cortisol group (p = 0.02). The widths of the chloride cells were 7.718 ± 0.3 μm and 7.922 ± 0.4 μm in the cortisol and control groups which were without any significant differences. Both the dispersion and numbers of chloride cells in four locations (on the filament basement of the lamellae interlamellar region and on the lamellae) were significantly different (p = 0.01) between the two experimental groups.
Conclusion: exogenous cortisol can cause significant cellular and morphometric changes in gills of the Persian sturgeon fry for their adaptation to salinity.