Over the past 50 years there has been a concerning decline in male reproductive health and increase in male infertility which is now recognized as a major health concern globally. While male infertility can be linked to some genetic and lifestyle factors, these do not fully explain the rate of declining male reproductive health. Increasing evidence from human and animal studies suggests that exposure to ubiquitously found environmental chemicals (ECs) may in part play a role. Many studies on chemical exposure however, have assessed the effects of exposure to individual ECs, usually at levels not relevant to everyday human exposure. There is a need for study models which reflect the "real-life" nature of EC exposure. One such model is the biosolids treated pasture (BTP) sheep model which utilizes biosolids application to agricultural land to examine the effects of exposure to low level mixtures of chemicals. Biosolids are the byproduct of the treatment of wastewater from industrial and domestic sources and so their composition is reflective of the ECs to which humans are exposed. Over the last 20 years the BTP sheep model has published multiple effects on offspring physiology including consistent effects on the male reproductive system in fetal, neonatal, juvenile, and adult offspring. This review focuses on the evidence from these studies which strongly suggests that low-level EC exposure during gestation can alter several components of the male reproductive system and highlights the BTP model as a more relevant model to study real-life EC exposure effects.
Reproduction (Cambridge, England). 2024 Jun 01 [Epub ahead of print]
Michelle Bellingham, Neil Evans
M Bellingham, School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, United Kingdom of Great Britain and Northern Ireland., N Evans, School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, United Kingdom of Great Britain and Northern Ireland.