Toxicological Comparison of Mancozeb and Zoxamide Fungicides at Environmentally Relevant Concentrations by an In Vitro Approach

• Main Authors: Gabriele Lori, Roberta Tassinari, Laura Narciso, Ion Udroiu, Antonella Sgura, Francesca Maranghi, Sabrina Tait
• Format: Article
• Language: English
• Published: MDPI AG 2021-08-01
• Series: International Journal of Environmental Research and Public Health
• Subjects: gene expression; genotoxicity; pesticides; reactive oxygen species; risk assessment
• Online Access: https://www.mdpi.com/1660-4601/18/16/8591

Mancozeb (MZ) and zoxamide (ZOX) are fungicides commonly used in pest control programs to protect vineyards. Their toxic and genotoxic potential were investigated in vitro on HepG2 and A549 cell lines at environmentally relevant concentrations. Cytotoxicity, apoptosis, necrosis and intracellular reactive oxygen species (ROS), comet assay and a micronucleus test with CREST immunofluorescence were used. The expression of a panel of genes involved in apoptosis/necrosis (<i>BAX/BCL2</i>), oxidative stress (<i>NRF2</i>), drug metabolism (<i>CYP1A1</i>) and DNA repair (<i>ERCC1/OGG1</i>) was evaluated by real-time PCR. Both fungicides were cytotoxic at the highest tested concentrations (295.7 and 463.4 µM, respectively); MZ induced necrosis, ZOX did not increase apoptosis but modulated <i>BAX</i> and <i>BCL2</i> expression, suggesting a different mechanism. Both compounds did not increase ROS, but the induction of <i>CYP1A1</i> and <i>NRF2</i> expression supported a pro-oxidant mechanism. The comet assay evidenced MZ genotoxicity, whereas no DNA damage due to ZOX treatment was observed. Positive micronuclei were increased in both cell lines treated with MZ and ZOX, supporting their aneugenic potential. <i>ERCC1</i> and <i>OGG1</i> were differently modulated, indicating the efficient activation of the nucleotide excision repair system by both fungicides and the inhibition of the base excision repair system by MZ. Overall, MZ confirmed its toxicity and new ZOX-relevant effects were highlighted.