Histomorphological changes in testes of broad-snouted caimans (Caiman latirostris) associated with in ovo exposure to endocrine-disrupting chemicals

Abstract

Studies regarding the effects of endocrine-disrupting chemicals (EDCs) on the reproductivefunctions of wild animals have raised increasing concern. Thus, here we evaluated theconsequences of in ovo exposure to endosulfan (END) and bisphenol A (BPA) in testes fromneonatal to juvenile (Juv) caimans (Caiman latirostris). Caiman eggs were collected from areaswith low to moderate anthropogenic intervention and incubated at male-producing temperature.At stage 20 of embryonic development (previous to gonad sex determination), eggs were exposedto either END (20 ppm) or BPA (1.4 ppm) and male gonad histomorphology examined in 10-day-old, 90-day-old, and Juv caimans. The relative seminiferous tubular area (RTA) was measuredin testes and the proliferation index and the expression of estrogen receptor alpha (ERa) werequantified in intratubular cells. Regardless of the treatment, all eggs resulted in male hatchlings.The testes of EDC-exposed caimans presented tortuous seminiferous tubules with empty tubularlumens. The RTA of 10-day-old caimans exposed to BPA was decreased. The percentage of cellsexpressing ERa was not different after in ovo treatment with EDCs (compared to the Controlgroup), although caimans exposed to END showed a different ERa distribution pattern. Theproliferation index was lower in 90-day-old caimans exposed to END, and higher in Juv caimansexposed to BPA. In ovo exposure to END or BPA modified sensitive parameters of C. latirostris malegonads. The alterations described here might compromise not only the sexual maturation but alsothe reproductive performance of adult caimans.