Due to increasing evidence that microplastics have found their way into different biological systems, from blood to lungs, researchers have become interested in identifying and understanding the potential impact of microplastics on reproductive systems, as well. A study recently published in Toxicological Sciences has examined microplastics and their presence in male reproductive organs. Infertility involves the inability to conceive after 1 year of unprotected sex. In recent decades, there has also been a noted decline in sperm counts worldwide.They obtained canine testis tissues from routine dog neuter surgeries and anonymized samples from men via the New Mexico Office of the Medical Investigator. Altogether, the research included samples from 47 dogs and 23 men.
Researchers identified 12 different microplastic types in the dog and human testis samples. They found that the amount of microplastics in men was about three times higher than in dog reproductive tissue.
Among humans and dogs, the most common type of polymer was polyethylene (PE), and the second most common was polyvinyl chloride (PVC).PE is commonly used in packaging, water supply systems, and agricultural films. PVC is also very common, used in construction, medical equipment, packaging, and insulation for electronics. Interestingly, researchers did not find an association between PE and the observed properties, though PVC was associated with decreases in testis weight. Thus, it is possible that microplastics negatively affect male fertility, but more research is required. Since the research that focused on fertility used data from dogs, more research is needed to see how this corresponds to people. First, it looked at a relatively small number of tissue samples obtained from one area of the United States. Further research examining even more samples from a more comprehensive data pool may be helpful.
Second, the human tissue samples were from 2016, which could have impacted the results. Researchers also acknowledge that the humans from which samples came typically did not experience natural deaths, so experts cannot broaden the results to an entire population.
Their approach to analyzing tissue samples also requires further refinement, and researchers presumed that some smaller nanoparticles could have been lost in ultracentrifugation. Ultimately, the study authors noted that their research “highlights the need to determine the dose-response effects of these microplastics and to conduct mechanistic studies on the reproductive system.”
