A comprehensive approach to health assessment of fish population using head kidney derived macrophages (HKM) and macrophage aggregates (MA) from rohu (Labeo rohita) and tilapia (Oreochromis sp.): the potentially sensitive biomarkers of contaminant exposure and several environmental stressors
*Srikanta Guria
Post Graduate Department of Zoology, Barasat Govt. College, Barasat, Kolkata-700124 (India) *Corresponding author: Dr. Srikanta Guria, Assistant Professor E-mail: guriasrikanta@gmail.com, srikantaguria81@gmail.com
ABSTRACT
Macrophages are key cells in both the innate and the adaptive immune system. The head kidney in teleost fish is a primary hematopoietic organ and act like bone marrow. Among head kidney leukocytes (HKL) only macrophages show the unique property of adherence on slides. The aim of the present study was to investigate the head kidney macrophages (HKM) morphology and phagocytic behavior in teleosts. Tissues from head kidney were removed and mashed in (0·1) M phosphate buffer saline (pH 7·2) in presence of trypsin- EDTA and tryton X 100. From cell suspension, adherent macrophages were stained by Giemsa. Presence of lysosomes was indicated using neutral red staining. Activated charcoal particles in normal saline (0·9% NaCl) was used for phagocytosis study. Light microscopy observations showed numerous macrophages as free macrophages or in aggregates (MAs). Formation of pseudopodia, attachment of charcoal particle on macrophage surface, tendency of cell fusion was noticed. Some cell also exhibited small vacuoles in cytoplasm. Macrophage aggregates (MAs), morpho-functional alteration of macrophages can be used as bio indicator to several environmental stressors which should be of great value as a first-line indicator early warning system of environmental pollution.