10:00-10:20 Reproductive function in a polluted world: lessons from animal models

Exposure to environmental chemicals during fetal and pre-pubertal development has been associated with perturbed mammalian reproductive development and function. Indeed, there is increasing evidence that chemical contaminants adversely impact the developing fetus in utero, the pre-pubertal infant and the adult. In the male, chemical exposures have been associated with sub-fertility, malformations at birth and testicular cancer and in the female, with precocious puberty, premature menopause and polycystic ovarian disease. Although temporal changes and geographical differences in human reproductive function are indicative of an environmental aetiology, determining underlying mechanisms and true cause and effect is problematic. Developmental and functional impacts of individual or chemical mixtures are explored using three animal models. (1) Pregnant ewes exposed to chemical mixtures in widely used sewage sludge derived fertiliser (biosolids) provide a model of real-life human exposure. (2) Companion dogs that share our homes serve as a sentinel species for human exposure to household pollutants. (3) Neonatal mouse gonads exposed in vitro to selected chemicals provide information on subtle perturbations of early gonadal development. (1: sheep) Exposure induced changes in the transcriptome (testis and ovary) are reported combined with altered fetal gonadal morphology and endocrine function. (2: dog) a decline in dog semen quality over 26 years parallels that reported in the human. Regional differences in chemical profiles and morphology also approximate those reported in the human. Specific chemical contaminants alter semen function at environmental/tissue concentrations. (3: mouse) gonadal concentrations of chemicals alter follicle development in the early post-natal ovary and perturb cellular development in the testis. Details on each of these paradigms will be presented. This combination of animal models has provided key insights into possible chemical perturbations of human fertility and reproductive health.