Summary
Growing worries about microplastics and nanoplastics have led scientists to question whether these particles might infiltrate the male reproductive system and affect fertility, yet hard data in humans has been scarce. This study tackled that gap by using highly sensitive pyrolysis-GC/MS techniques to measure and characterize 12 types of microplastics in 47 canine testes and 23 human testes, while also examining reproductive organ weights and sperm counts in dogs. Microplastics were detected in every single testis sample, with humans showing even higher average levels (328.44 µg/g) than dogs (122.63 µg/g), and with substantial variability among individuals. Both species shared similar polymer profiles, dominated by polyethylene (PE), though the presence of other polymers such as PVC and PET showed negative correlations with testis weight, raising concerns about functional consequences. The findings reveal that microplastic contamination of the male reproductive system is not only widespread but also potentially linked to changes in testicular health, underscoring the possibility that these particles could contribute to declining sperm quality and broader fertility issues in mammals.
PMID: 38745431
PMCID: PMC11285152
DOI: 10.1093/toxsci/kfae060
Abstract
The ubiquitous existence of microplastics and nanoplastics raises concerns about their potential impact on the human reproductive system. Limited data exists on microplastics within the human reproductive system and their potential consequences on sperm quality. Our objectives were to quantify and characterize the prevalence and composition of microplastics within both canine and human testes and investigate potential associations with the sperm count, and weights of testis and epididymis. Using advanced sensitive pyrolysis-gas chromatography/mass spectrometry, we quantified 12 types of microplastics within 47 canine and 23 human testes. Data on reproductive organ weights, and sperm count in dogs were collected. Statistical analyses, including descriptive analysis, correlational analysis, and multivariate linear regression analyses were applied to investigate the association of microplastics with reproductive functions. Our study revealed the presence of microplastics in all canine and human testes, with significant inter-individual variability. Mean total microplastic levels were 122.63 µg/g in dogs and 328.44 µg/g in humans. Both humans and canines exhibit relatively similar proportions of the major polymer types, with PE being dominant. Furthermore, a negative correlation between specific polymers such as PVC and PET and the normalized weight of the testis was observed. These findings highlight the pervasive presence of microplastics in the male reproductive system in both canine and human testes, with potential consequences on male fertility.
Keywords: male reproductive; particulates; polymers; pyrolysis GC/MS; sperm count; testis.
Hu CJ, Garcia MA, Nihart A, Liu R, Yin L, Adolphi N, Gallego DF, Kang H, Campen MJ, Yu X. Microplastic presence in dog and human testis and its potential association with sperm count and weights of testis and epididymis. Toxicol Sci. 2024 Aug 1;200(2):235-240. doi: 10.1093/toxsci/kfae060. PMID: 38745431; PMCID: PMC11285152.