Assessment of hepatotoxicity due to pollutants of Rio Doce through histopathological analysis in fish liver

• Grant number: 20/09297-0
• Support type: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): November 01, 2020
• Effective date (End): December 31, 2021
• Field of knowledge: Biological Sciences - Morphology - Histology
• Principal researcher: Denis Moledo de Souza Abessa
• Grantee: Kaori Onishi
• Home Institution: Instituto de Biociências (IB-CLP). Universidade Estadual Paulista (UNESP). Campus Experimental do Litoral Paulista. São Vicente , SP, Brazil

Abstract

The Doce River Basin represents a set of water bodies of high environmental and socioeconomic relevance. However, it has been historically impacted by several human activities. Studies have shown the high concentration of metals in river water and sediment, but organic pollutants that are also introduced and have been underestimated or even ignored so far. All of these substances can threat the aquatic biota, including the fish. In these organisms, the liver is a target organ for the metabolism of xenobiotics, thus it can be used as an indicator of metabolic and histopathological changes. This study aims to evaluate hepatotoxicity in fish from Doce river through the use of histopathological analysis of the liver of organisms collected in eight sampling sites along the river basin. Individuals of the species Rhamdia quelen and Pimelodus maculatus were already collected (15 animals per sampling site), weighed and sacrificed, and the livers were removed and fixed. For tissue analysis, slides will be prepared with 5 micrometer thick cuts and stained in Hematoxylin-Eosin. Afterwards, the slides will be analyzed by optical microscopy, following widely known criteria to identify and quantify the changes of different histopathological importance, classified according to the degree of reversibility of each lesion. The data obtained will be used to compare the health of individuals collected in different locations along the basin and to determine possible relationships between the pollutants levels in the Doce River and the hepatotoxic effects on fish.