Microplastics found in testicles: Concerns rise for human fertility

Scientists from the University of New Mexico in the United States researched the testicles of dozens of humans and dogs. The study discovered worryingly large amounts of microplastics. Preliminary results suggest that these could harm fertility, but experts emphasize that further research in this area is necessary.

The research team consisted of scientists who thoroughly examined 23 human testicles and 47 dog testicles. These studies aimed to check whether microplastics can be found in these organs. The researchers noted the presence of "significant amounts" of this material in the samples studied.

"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 who specializes in studying the impact of various factors on fertility. His studies have shown that the number of sperm produced by men can be affected by heavy metals, pesticides, or substances that disrupt hormone function. The noticeable global decline in male fertility in recent years prompted him to search for a new harmful factor.

In the research, scientists used human tissues from autopsies and dog tissues. For dogs, the researchers found an average of 66 micrograms of plastic per gram of tissue and 184 micrograms per gram for humans.

"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 were able to precisely determine not only the amount but also the types of plastics present in the examined tissues. The most commonly found plastic is polyethene (PE), which is used, for example, to make plastic bags and bottles. The second most common was polyvinyl chloride (PVC), which is used to produce, among other things, flooring, window and door frames, packaging, and components of various devices. Experiments on dogs showed that a decrease in sperm count accompanied polyvinyl chloride.

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

Dogs were chosen for the research because they live closely with humans and have significantly similar bodies. Physically, their spermatogenesis is closer to humans, and the sperm concentration is identical. Prof. Yu said 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 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 than there is now. This is not good news.

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

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.