Multibiomarker assessment in zebrafish Danio rerio after the effects of malathion and chlorpyrifos.

Object: Nowadays, organophosphates appear to be among the most used pesticides all over the world. Their amounts and amounts of their metabolites in surface water are expected to increase in the near future. In the light of potential organelles impairment, this work aims to investigate the effects of chlorpyrifos and malathion in environmentally relevant concentration on morphological and functional traits of zebrafish mitochondria and lysosomes. Methods: Adult zebrafish were exposed to widely used organophosphate pesticides namely malathion (5 and 50 µg L⁻¹) and chlorpyrifos (0.1 and 3 µg L⁻¹) for 14 days. The comprehensive set of biochemical markers that reflect oxidative/carbonyl/nitrosative stress and cytotoxicity (mitochondria swelling, lysosomal membrane stability, and cell damage) was determined in fish liver. Results: Chlorpyrifos and malathion in both concentrations were found to affect mitochondria and lysosome membranes: They caused a substantial decline in neutral red retention and an increase in mitochondria swelling. Also, the concentration-dependent enhancement of lactate dehydrogenase in blood was depicted. Even low pesticide concentrations were able to promote apoptosis and stimulated overproduction of methylglyoxal as reactive carbonyl species. We also revealed that reactive nitrogen species were sparked by organophosphates. This effect occurs only in animals treated with higher insecticides concentration. Moreover, the pesticides induced oxidative stress response measured by increasing of reactive oxygen species level (only after chlorpyrifos), as well as by variation in total antioxidant capacity with signs of deeper injury after chlorpyrifos exposure. The integrative biomarker response (IBR) index calculation supports the hypothesis that chlorpyrifos was significantly more toxic to zebrafish than malathion. Conclusion: Our study suggests that zebrafish markers can serve as a sensitive transferential model for evaluating mitochondrial and lysosomal toxicity of pesticides and extrapolating results to mammalian and human. [ABSTRACT FROM AUTHOR]