There Are Likely Microplastics in Your Testicles

Discovery suggests microplastics can breach special blood barrier, impact sperm counts
By Arden Dier,  Newser Staff
Posted May 21, 2024 9:40 AM CDT
Microplastics in Testicles May Be Affecting Sperm
Micro-plastic particles from rubber tires are seen under a microscope in this Feb. 19, 2020 image taken in a research lab at Oregon State University.   (Oregon State University via AP)

Tiny plastic particles have reached parts of our bodies once thought impossible, including placentas and breast milk and, as researchers show in a new study, every human testicle analyzed. The discovery, researchers say, could help explain why sperm counts are declining around the world. Microplastics were discovered in all the 23 human testes and 47 dog testes analyzed, per the Guardian. Sperm counts could not be taken from the preserved human testes, which came from cadavers, ages 16 to 88 at the time of death in 2016. But samples from the dog testes obtained through neutering operations showed low sperm counts accompanied high contamination with polyvinyl chloride, or PVC, which Greenpeace considers the "most environmentally damaging" plastic.

"PVC can release a lot of chemicals that interfere with spermatogenesis, and it contains chemicals that cause endocrine disruption," says Xiaozhong Yu, a professor in nursing at the University of New Mexico. Yu, lead author of the study published Wednesday in Toxicological Sciences, initially "doubted whether microplastics could penetrate the reproductive system"—"testes, like brains, have a special blood barrier," per Business Insider—so the results left him "surprised." He notes "the impact on the younger generation might be more concerning," given the proliferation of plastic in our modern environment. Microplastics have been found on the highest mountain peaks, in deep ocean trenches, and in our bloodstreams. A recent study found an increased risk of cardiovascular disease in those with microplastics in their blood.

But "limited data exists on microplastics within the human reproductive system and their potential consequences on sperm quality," per the study. Researchers discovered 12 types of microplastics in the human and canine testes. "Both humans and canines exhibit relatively similar proportions of the major polymer types, with [polyethylene or PE] being dominant," according to the study. However, human testes had nearly three times the microplastic levels as dog testes, with 328 micrograms per gram of tissue compared with 123 micrograms. Researchers also noted "a negative correlation between specific polymers such as PVC and [polyethylene terephthalate, or PET] and the normalized weight of the testis was observed." (More microplastics stories.)

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