Blood biomarkers of common toad Rhinella arenarum following chlorpyrifos dermal exposure

LAJMANOVICH, RAFAEL C; PELTZER P.,; ATTADEMO A.M.,; COLUSSI C.L.,; MARTINUZZI C

Interdisciplinary Toxicology

SETOX & IEPT CEM SASc

Año: 2018 vol. 11 p. 148 - 154

1337-6853

Chlorpyrifos (CPF) is a broad spectrum pesticide commonly used for insect control, has great affinity for lipids and is thus a potentialfor bioaccumulation in aquatic organisms. The aim of this study was to evaluate the toxicity of CPF using the common toad Rhinellaarenarum via dermal uptake in plastic bucket to simulate their natural exposition in ponds. R. arenarum toads were exposed individuallyto solutions containing a nominal concentration of a commercial formulation of CPF insecticide (5 and 10 mg/L). Different enzymebiomarkers (BChE: butyrylcholinesterase, CbE: carboxylesterase, and CAT: catalase) were measured in blood tissue after exposition.The capacity of pyridine-2-aldoxime methochloride (2-PAM) to reverse OP-inhibited plasma BChE and the ratio of heterophils andlymphocytes (H/L) as hematological indicators of stress were also determined. The normal values of plasma B-sterases (BChE and CbE)were highly inhibited (until ≈ 70%) in toads 48 h after exposure to CPF. The results indicate that 2-PAM produced BChE reactivationas well. The activity of CAT was also inducted for dermal exposure at more than double of that in the control toads (CPF; 5 mg/L).H/L ratios did not reveal a significantly increased stress. The study suggests that CPF via dermal uptake induced neurotoxicity andoxidative stress in the common toad R. areanum. Thus, some blood biomarkers employed in our study (i.e. BChE, CbE, 2-PAM, and CAT)might be used as predictors in health and ecological risk assessment of amphibian populations exposed to CPF.