A new study has emerged illustrating how little researchers are aware of the impact of chemicals on the human body. Bisphenol A, (BPA), is a chemical widely in plastic bottles, the lining of food and beverage cans and thermal receipts. The study published in the journal PLOS Genetics reveals that BPA breaks down DNA interactions needed to create sperm.
The researchers used mice models to investigate the impact of environmental causes on sperm count as the reason for declining sperm counts since the 1990s has been unknown. Studies have emerged implicating endocrine disuptors such as BPA, plastic-softening phthalates and estradiol.
Newborn male mice were given oral doses of BPA and were also to the synthetic estrogen ethinyl estradiol. The researchers exposed the developing testis and saw that the sperm of exposed animals did a poorer job of meiosis, the process in which cells combine the genetic information of their parents. As a result, more sperm died.
“We have a window of just a few days and we permanently change the way that the testis makes sperm in the adult,” said Hunt. “This mouse model would suggest that here’s actually a reason why these sperm counts would be falling, said WSU geneticist and principle investigator Pat Hunt. “We’re actually doing something to this process that’s going to cause the death of more cells as they’re trying to make sperm. They’re going to get culled out by this quality-control mechanism and the upshot of that will be that if you do enough of this, you’ll drop sperm counts.”
Lisa A. Vrooman, Jon M. Oatley, Jodi E. Griswold, Terry J. Hassold, Patricia A. Hunt. Estrogenic Exposure Alters the Spermatogonial Stem Cells in the Developing Testis, Permanently Reducing Crossover Levels in the Adult. PLOS Genetics, 2015; 11 (1): e1004949 DOI: 10.1371/journal.pgen.1004949