Researchers identify microplastics in human testicular tissue

Last week, researchers at the University of New Mexico (UNM) published a study in Toxicological Sciences identifying the presence of microplastics in human and canine testes. Among the 47 canine and 23 human testes analyzed, researchers identified 12 microplastics that may impact male reproductive health and fertility.

In a conversation with Matthew Campen, PhD, a professor at the UNM College of Pharmacy, Xiaozhong “John” Yu, MD, PhD, MPH, a professor at the UNM College of Nursing, lead author of the study, considered the potential impacts of microplastics on the decline in reproductive potential. Campen had conducted a similar study on the human placenta, which inspired Yu’s study on testicular tissue.

Yu told UNM, “Our study revealed the presence of microplastics in all human and canine testes.”

The researchers looked at human testicular tissue samples for the New Mexico Office of the Medical Investigator, which collects autopsy samples and stores them for up to seven years. Each of the samples was anonymized. In addition, the investigators looked at canine tissue samples from the City of Albuquerque animal shelters and private veterinary clinics that conduct neutering operations.

“Compared to rats and other animals, dogs are closer to humans,” Yu said. “Physically, their spermatogenesis is closer to humans and the concentration has more similarity to humans. We believe dogs and humans share common environmental factors that contribute to their decline.”

Each tissue sample was chemically treated to dissolve the fat and proteins before being spun in an ultracentrifuge. A pellet of plastic left at the bottom of the centrifuged sample was heated and analyzed using a mass spectrometer.

The canine samples revealed 122.63 micrograms of microplastics per gram of tissue. Comparatively, human testicular tissue had 329.44 micrograms of microplastics per gram of tissue. According to the UNM press release, the concentration of microplastics in human testicular tissue was significantly greater than in Campen’s study in the placenta.

A deeper analysis revealed that polyethylene was the most common type of plastic in human and canine tissue.

“The plastic makes a difference — what type of plastic might be correlated with potential function,” he added. “PVC can release a lot of chemicals that interfere with spermatogenesis, and it contains chemicals that cause endocrine disruption.”