Effects of endocrine disruptors on broad-snouted caiman (Caiman latirostris Daudin 1802).

STOKER C; MUÑOZ-DE-TORO M; LUQUE E H

Mar del Plata

Congreso; II Congreso Argentino de la Sociedad de Toxicología y Química Ambiental (SETAC); 2008

Wastes originated from human activity (industry, agriculture, urban centers) generate pollution that contaminates wetlands and rivers, thus affecting wildlife and the whole ecosystem health. Many of these pollutants act as endocrine disruptors (EDs). A native species particularly exposed to EDs is the broad-snouted caiman. Ongoing studies in our laboratory, attempt to determine the impact of EDs exposure on caiman health and reproductive biology. We hypothesize that exposure to EDs, during histogenesis and organogenesis in the developing caiman embryo and/or early in life cause developmental alterations responsible for reproductive failure, impaired immune system function and altered behavior in adulthood. We have identified and characterized biomarkers of prenatal/postnatal exposure to EDs, such as bisphenol A, atrazine and endosulfan, in hatchlings and juvenile caimans. We demonstrated that prenatal exposure to EDs dramatically alters the fate of the caiman bipotential gonad inducing complete sex reversal or disrupting gonad histoarchitecture. The affected female gonad exhibited altered follicular dynamics and high incidence of multiovular follicles, while male gonad exhibited altered myoid cell distribution and increased apoptosis in seminiferous tubular cells. Besides that, levels of sex steroid hormones were modified in pollutant exposed males and females. We also demonstrated that, in ovum exposure to pesticides increased the eggs weight loss and decreased hatchlings weight of Caiman latirostris. An ELISA to quantify caiman vitellogenin, a tool to study female caiman reproductive biology and to assess environmental estrogen exposure, was developed. Moreover, persistent organochlorine compound (OCC) concentrations in Caiman latirostris eggs were measured as indicators of wetlands pollution. Results showed, high presence of OCC in caiman eggs verifying high level of exposure to EDs. Exposure of the developing embryo to EDs in the detected concentrations could alter reproductive performance in adulthood and drastically interfere with population stability of this top predator. Eventhough we have provided valuable information for caiman conservation, we still have a long way to go for a better understanding of endocrine disruptor effects on Caiman latirostris health and reproductive biology.