Microplastics found in human and dog testicles, fertility at risk

Researchers from the University of New Mexico in the United States conducted detailed studies on the testicles of dozens of humans and dogs. The study discovered worryingly large amounts of microplastics. Preliminary results suggest these particles could negatively impact fertility, but experts emphasize that further research is necessary.

The research team thoroughly examined 23 human testicles and 47 dog testicles to check whether microplastics could be found in these organs. The researchers noted the presence of "significant amounts" of this material in their samples.

— Our study demonstrated the presence of microplastics in all the human and dog testicles examined, — said Prof. Xiaozhong "John" Yu, the author of the work published in the journal "Toxicological Sciences."

Professor Yu is an expert specializing in the impact of various factors on fertility. His studies have shown that heavy metals, pesticides, and substances that disrupt hormone function can affect sperm production. The noticeable global decline in male fertility in recent years prompted him to search for new harmful factors.

In the research, scientists used human tissues from autopsies and dog tissues. For dogs, the researchers found an average of 1.89 micrograms of plastic per ounce of tissue, and for humans, 5.21 micrograms per ounce.

— Initially, I doubted that microplastics could penetrate the reproductive system. When I received the first results regarding dogs, I was surprised. I was even more astonished by the results concerning humans, said Prof. Yu.

Thanks to the latest analytical methods, scientists precisely determined the amount and types of plastics present in the examined tissues. The most commonly found plastic was polyethylene (PE), used to make plastic bags and bottles. Polyvinyl chloride (PVC) was the second most common, used in flooring, window and door frames, packaging, and various devices. Experiments on dogs showed that a decrease in sperm count accompanied polyvinyl chloride.

— The type of plastic matters. PVC can release large amounts of substances that affect spermatogenesis. It also contains compounds that disrupt hormone function, warns Prof. Yu.

Dogs were chosen for the research for two reasons: they live closely with humans and have bodies that are significantly similar to humans. Physically, their spermatogenesis is closer to that of humans, and their sperm concentration is identical. Prof. Yu stated that humans and dogs share common environmental factors contributing to the decline in sperm count.

Researchers remind us that microplastics come from various plastic-made objects that gradually degrade in the environment. These particles are carried by wind and water and are now found practically everywhere.

The average age of the men whose tissues were examined was 35 years, indicating that exposure to plastic began decades ago when there was less plastic in the environment. This is not good news.

— The impact on younger generations could be even more concerning now that there is more plastic in the environment than ever before, warns the specialist.

The results indicate the need for further research to determine how microplastics might affect sperm production in the testicles. Scientists still do not know the long-term effects of microplastics on the body.