Oxidative effects of the acute exposure to a pesticide mixture of cypermethrin and chlorpyrifos on carp and zebrafish - A comparative study.

The use of commercial pesticides combinations increases the risk of intoxication in non-target aquatic organisms. Here, we investigate the potential of a commercial pesticide formulation containing (CYP) plus chlorpyrifos (CPF) to induce oxidative damage on two fish species (common carp and zebrafish). Carp and zebrafish were exposed for 96 h under laboratory conditions. Fish were divided in three different groups: CTL, 0.3 µg L-1 or 0.6 µg L-1 of CYP and 0.5 or 1 µg L-1 of CPF in commercial formulation. Both carp and zebrafish showed an increase in lipid peroxidation (LPO) and glutathione-S-transferase (GST) activity when compared to control group. Other oxidative parameters responded differently to exposure in carp and zebrafish. There were an increase in ascorbic acid (ASA) levels and decrease in catalase (CAT) activity and non-protein thiols (NPSH) levels in treated groups of carps. In the other hand, zebrafish showed significant decrease in ASA and increase in CAT activity and NPSH levels. Overall, we demonstrate noxious effects on redox parameters in two fish experimental models and different effects were observe in each fish species exposed to commercial pesticide formulation. This difference responses observed can be related with specific mechanisms of detoxification and antioxidant defense system of each species.

Inorganic mercury exposure in drinking water alters essential metal homeostasis in pregnant rats without altering rat pup behavior.

The aim of this work was to investigate the effects of HgCl2 exposure in the doses of 0, 10 and 50µg Hg2+/mL in drinking water during pregnancy on tissue essential metal homeostasis, as well as the effects of HgCl2 exposure in utero and breast milk on behavioral tasks. Pregnant rats exposed to both inorganic mercury doses presented high renal Hg content and an increase in renal Cu and hepatic Zn levels. Mercury exposure increased fecal Hg and essential metal contents. Pups exposed to inorganic Hg presented no alterations in essential metal homeostasis or in behavioral task markers of motor function. In conclusion, this work showed that the physiologic pregnancy and lactation states protected the offspring from adverse effects of low doses of Hg2+. This protection is likely to be related to the endogenous scavenger molecule, metallothionein, which may form an inert complex with Hg2+.