HISTOMORPHOLOGICAL CHANGES IN THE TESTES OF BROAD-SNOUTED CAIMANS (CAIMAN LATIROSTRIS) ARE ASSOCIATED WITH IN OVO EXPOSURE TO ENDOCRINE-DISRUPTING CHEMICALS

DURANDO MILENA; COCITO, LAURA L.; CANESSINI GUILLERMINA; GALOPPO GERMÁN; LUQUE ENRIQUE; MUÑOZ-DE-TORO MÓNICA

Congreso; Congreso latinoamericano de Toxicología clínico-laboratorial, Toxilatin,; 2014

Introduction: Many studies in wildlife have raised concern regarding endocrine- disrupting chemicals (EDCs) effects on reproductive functions. Caiman latirostris, has a wide distribution in the wetlands and rivers of northeastern Argentina, southern Brazil, Paraguay, Uruguay and Bolivia. Previously, we have demonstrated that in ovo exposure to bisphenol A (BPA) or endosulfan (END) affects the proliferation/apoptosis balance of testicular cells, the testosterone circulating levels and, the mRNA expression of sex-determining genes in male hatchlings caimans. Objective: The aim of this study was to evaluate the consequences of in ovo exposure to END and BPA in Caiman latirostris testes from neonatal to juvenile. Materials and Methods: Caiman eggs were collected from areas with low to moderate anthropogenic intervention and incubated in controlled conditions at male producing temperature (33ºC). At stage 20 of embryonic development, the sensitive stage for gonadal sex determination, eggs (n=57) were exposed to END (20 ppm) or BPA (1.4 ppm); control animals (C) received ethanol (50 ul). Male gonadal histo-morphology was examined in caimans at the age of 10 days (10 d); 90 d or juvenile (Juv, sacrificed when body mass was higher than 1 Kg). The relative area of seminiferous tubules (RTA) was measured by image analysis in sections stained with Picrosirius-haematoxilin. By immunohistochemistry, the proliferation index (PI) and the expression of estrogen receptor alpha (ERa) was analyzed using anti-proliferating cell nuclear antigen (clone PC-10) and anti-ERa (LETH-ER-202y) antibodies, respectively. PI and ERa expression were quantified as percentage of positive immunostained intratubular cells.Results: Independently of the treatments, all the eggs incubated at 33ºC resulted in male hatchlings. Neither END nor BPA affected the hatchling growth rate, since all animals were healthy and no differences in body mass, total length and snout?vent length were recorded respect to C group at hatch. Tortuous seminiferous tubules with empty tubular lumens characterized the testes of EDC exposed caimans. The RTA was modified due to exposure to EDCs: END increase the RTA in Juv (C: 0.55±0.01 vs END: 0.62±0.01), while BPA decreased the RTA at 10 d (C: 0.50±0.01 vs BPA: 0.43±0.02). Expression of ERa protein was not different after in ovo treatment with END or BPA. The PI measured in intratubular cells was lower in caimans of 90 d exposed to END (C: 71.9±1.7 vs END: 62.8±1.9), while treatment with BPA increased PI in Juv caimans (C: 55.0±4.0 vs BPA: 76.1±3.0). Conclusions: In ovo exposure to widely used EDCs: END and BPA modified sensitive parameters on C. latirostris male gonad. Alterations described here could have a detrimental effect on sexual maturation and, ultimately, could comprise the success of male caiman reproduction.