New research by scientists at the University of Nottingham suggests that environmental contaminants found in the home and diet have the same adverse effects on male fertility in both humans and in domestic dogs.
There has been increasing concern over declining human male fertility in recent decades, with studies showing a 50% global reduction in sperm quality in the past 80 years. A previous study by the Nottingham experts showed that sperm quality in domestic dogs has also sharply declined, raising the question of whether modern day chemicals in the home environment could be at least partly to blame.
In a new paper published in Scientific Reports, the Nottingham team set out to test the effects of two specific human-made chemicals—namely, the common plasticizer DEHP, widely abundant in the home (in carpets, flooring, upholstery, clothes, wires, toys) and the persistent industrial chemical polychlorinated biphenyl 153, which although banned globally, remains widely detectable in the environment, including in food.
The researchers carried out identical experiments in both species using samples of sperm from donor men and stud dogs living in the same region of the UK. The results show that the chemicals, at concentrations relevant to environmental exposure, have the same damaging effect on sperm from both man and dog.
Leading the work, Associate Professor and Reader in Reproductive Biology at the School of Veterinary Medicine and Science, Richard Lea, said, “This new study supports our theory that the domestic dog is indeed a ‘sentinel’ or mirror for human male reproductive decline and our findings suggest that human-made chemicals that have been widely used in the home and working environment may be responsible for the fall in sperm quality reported in both man and dog that share the same environment.”