TOXICOLOGICAL APPLICATION OF LOGGERHEAD SEA TURTLE (CARETTA CARETTA) CULTURED ERYTROCYTES

Juvenile loggerhead turtles (Caretta caretta) can be considered a good indicator species for monitoring environmental contaminants that can mimic steroid hormone signaling. However, due to the legal constraints of their endangered status, the impact of environmental pollutants on nuclear steroid hormone receptor-mediated signaling is still poorly investigated in sea turtles. Here we describe the use of an in vitro toxicity testing for evaluating the effects of different environmental exogenous estrogens on the expression of C. caretta estrogen receptor (ER). In this regard, primary cultures of erythrocytes were exposed to increasing concentrations of 4-nonylphenol (4-NP), Diisodecyl phthalate (DiDP) and Tri-m-cresyl phosphate (TMCP) for 48 h. A real time quantitative PCR assay, optimized in the loggerhead turtles red blood cells (RBCs), showed significantly increased levels of ER mRNA in a dose-dependent manner after 48 h exposure to both 4-NP and TMCP. Interestingly, the dosage-dependent effects of DiDP on ER expression were opposite in comparison to that obtained following exposure to the other tested compounds. Our work demonstrates the validity of cultured erythrocytes in sea turtles suggesting that this approach could provide an understanding of the impact of environmental contaminants on an endangered species in a minimally invasive manner.