Morphofunctional changes in liver melanomacrophages of fish and amphibians induced by the contaminant benzo [a] pyrene

Author(s)

Lara Zácari Fanali

• Document type: Doctoral Thesis
• Press: São José do Rio Preto. 2020-07-02.
• Institution: Universidade Estadual Paulista (Unesp). Instituto de Biociências Letras e Ciências Exatas. São José do Rio Preto
• Defense date: 2020-03-27
• Advisor: Classius de Oliveira

Abstract

Fish and amphibians are vulnerable to various pollutants. Benzo[a]pyrene (BaP) is a contaminant with toxic properties. Metabolized by the enzyme P450 (CYP1A1) produces toxic byproducts. Known as a CYP1A1 inhibitor, α-naphtoflavone (aNF) prevents BaP metabolism and the generation of toxic metabolites. aNF is an exogenous compound and is not known for its effect on organs and tissues. The liver is the major source of catalyzing enzymes for biotransformation reactions. The susceptibility of the organ to damage by chemical agents is a consequence of its role in metabolism. However, animals have developed mechanisms to detect and respond to these chemicals. Melanomacrophages (MMs) are involved in this process due to their detoxification function. Thus, our objectives were to evaluate the effects of BaP and/or aNF on MMs and genotoxic effects of compounds. The animals were exposed to 2mg/kg BaP and/or 20mg/kg aNF for 48 hours and 7 days. After the experiments, the procedures for light microscopy, fluorescence, spectrophotometry and genotoxic analysis were followed. In fish, after 7d there was a decrease in melanin area, due to a inhibition of BaP in the melanogenic pathway; melanosome aggregation by interference in actin filaments; and increased frequency of micronucleus by the genotoxic potential of the compound. In anurans, at 48h, there was an increase in melanin production in BaP treatments, due to the antioxidant role of melanin; decreased phagocytosis by interfering with this function; decreased melanin synthesis in the BaP + aNF group, caused by the toxicity of both compounds; and reduction of abnormalities, by remaining in the blood only the least damaged erythrocytes. At 7d, there was no change, as the organisms have a maximum tolerance level of response to xenobiotics. (AU)

• FAPESP's process: 17/07971-2 - Morphofunctional changes in hepatic melanomacrophages of Physalaemus cuvieri (Anura: Leptodactylidae) induced by the contaminant benzo[alpha]pyrene.
• Grantee: Lara Zácari Fanali
• Support Opportunities: Scholarships in Brazil - Doctorate