Study Finds microplastics in human testicular tissue

In a study published in the Toxicological Sciences journal, University of New Mexico researchers have detected significant concentrations of microplastics in the testicular tissue of both humans and dogs, adding to growing concern about their possible effect on human reproductive health.

Microplastics are tiny plastic particles, less than 5 millimetres in size, that result from the breakdown of larger plastic debris or are manufactured for use in products like cosmetics and cleaning agents. These particles are pervasive in the environment, infiltrating air, water, and food supplies.

Emerging research suggests that microplastics may pose health risks to humans, potentially causing inflammation, disrupting hormones, and contributing to disease development due to their chemical composition and the pollutants they may carry.

In the study, Xiaozhong John Yu, a professor at the UNM College of Nursing, and his team obtained anonymized human tissue from the New Mexico Office of the Medical Investigator, which collects tissue during autopsies and stores it for seven years before disposal.

The team chemically treated the samples to dissolve the fat and proteins and further heated the samples as different types of plastic burned at specific temperatures.

The results showed that in canines, the average concentration of microplastics in testicular tissue was 122.63 micrograms per gram of tissue. In human tissue, the average concentration was 329.44 micrograms per gram – nearly three times higher than in canines and significantly higher than the average concentration found in placental tissue.

The researchers identified polyethylene (PE), commonly used to make plastic bags and bottles, as the most prevalent polymer in both human and canine tissue.

“Compared to rats and other animals, dogs are closer to humans. Physically, their spermatogenesis is closer to humans and the concentration is more similar to humans. Our study revealed the presence of microplastics in all human and canine testes. The team was also able to quantify the amount of microplastics in the tissue samples that revealed correlations between certain types of plastic and reduced sperm count in the canine samples,” said Yu. 

Reference: Chelin Jamie Hu, Marcus A Garcia, Alexander Nihart, Rui Liu, Lei Yin, Natalie Adolphi, Daniel F Gallego, Huining Kang, Matthew J Campen, Xiaozhong Yu, Microplastic presence in dog and human testis and its potential association with sperm count and weights of testis and epididymis, Toxicological Sciences, 2024;, kfae060, https://doi.org/10.1093/toxsci/kfae060