Exfoliative liver cytology in Oreochromis mossambicus as a bio-assessment tool for aquatic pollution

Abstract

The use of exfoliative cytology as a bio-assessment tool was evaluated to (1) identify and describe different cell types of normal liver cytology of Oreochromis mossambicus, (2) identify and describe changes in the cell types after exposure to cadmium and zinc, and (3) determine if non-imaging-guided fine-needle aspiration (FNA) cytology can be performed without sacrificing the fish. All fish used in the aspiration experiment recovered and survived. Livers of O. mossambicus exposed to cadmium and zinc showed excess numbers of exfoliated red blood cells, loss of cellular cohesion, regenerative hyperplasia, pale and weak cytoplasm staining, pronounced vacuolation and degeneration. Cadmium and zinc exposure induced pathological cellular changes. Exfoliative cytology is thus a safe, cost-effective and reliable bio-assessment tool.