Microplastics and Nanoplastics: Emerging Threats to Male Reproductive Health, Spermatogenesis, and Fertility

Abstract Microplastics and nanoplastics (MNPs) are now detected in human semen, testicular tissue, and the male reproductive tract. Chronic exposure disrupts spermatogenesis, reduces sperm count/motility/morphology, and impairs testosterone production through oxidative stress, inflammation, blood-testis barrier disruption, and endocrine effects of plastic additives (phthalates, BPA). Emerging data also link MNPs to increased prostate cancer risk via similar pathways. This perspective reviews the mechanisms and evidence linking MNPs to male infertility and prostate carcinogenesis and proposes interaction-mediated therapeutic strategies under the Cythera Bio platform as a proactive countermeasure. This paper is also available at: https://doi.org/10.5281/zenodo.19751579

Figure 1. Exposure pathways and bioaccumulation of microplastics and nanoplastics in the male reproductive system, including direct effects on spermatogenesis and prostate tissue. 

1. Exposure and BioaccumulationMNPs enter the male reproductive system via ingestion, inhalation, and possibly transdermal routes. Smaller nanoplastics readily cross biological barriers, including the blood-testis barrier, leading to direct accumulation in seminiferous tubules, epididymis, and prostatic tissue.  Although larger microplastics often receive more attention, nanoplastics may represent a more biologically consequential fraction because their smaller size may enable deeper tissue penetration, broader biodistribution, and easier passage across sensitive biological barriers.

2. Mechanisms of Reproductive Toxicity

• Oxidative stress and ROS generation damage sperm DNA and impair mitochondrial function.

• Chronic inflammation disrupts spermatogonial stem cells, Sertoli cell support, and prostate epithelium.

• Endocrine disruption by leached additives (phthalates, BPA) alters testosterone/FSH/LH balance and promotes hormone-sensitive prostate cell proliferation.

• Per the Z-Model, nanoplastics’ high accessible surface area amplifies these effects at low concentrations.

3. Clinical and Experimental Evidence Animal and emerging human studies show reduced sperm parameters, increased DNA fragmentation, and histological testicular damage. Recent NYU poster data further suggest associations between MNP exposure and prostate cancer risk markers, consistent with endocrine disruption and chronic inflammation pathways observed in hormone-sensitive tissues.

4. Biomonitoring and the Role of Scalable Urine Testing in Male Reproductive Health

A major barrier in understanding the reproductive impact of microplastics and nanoplastics in men is the lack of scalable human monitoring tools that can be used repeatedly over time. Many current studies rely on small cohorts, specialized laboratory workflows, or isolated measurements that provide limited insight into dynamic exposure patterns or fertility outcomes.

Urine-based testing may offer a practical pathway for exposure stratification, longitudinal monitoring, and comparison of healthy individuals with those experiencing infertility, abnormal semen parameters, hormonal disruption, or genitourinary disease. Repeated measurements may help identify occupational risk, environmental hotspots, lifestyle contributors, treatment response, and associations with spermatogenesis or endocrine function.

Under the ecotera health platform, a scalable urine testing system is in development for research, clinical monitoring, and decentralized at-home data collection. Such tools may help accelerate epidemiology, fertility research, and future precision intervention strategies in male reproductive health.

5. Therapeutic Opportunities Interaction-mediated mitigation (aggregation/sequestration without polymer degradation) offers a biologically relevant approach: larger aggregated particles are less likely to cross the blood-testis barrier and have reduced reactive surface area. Cythera Bio’s S1P-targeted LNPs delivering AI-identified natural compounds (antioxidants, anti-inflammatory agents) can protect spermatogenesis and prostate tissue while addressing MNP burden. This dual-action strategy aligns with longevity and space-medicine goals where combined stressors accelerate reproductive decline.

Figure 2. Mechanisms of microplastic and nanoplastic toxicity in male reproductive health and prostate cancer risk, alongside interaction-mediated mitigation and targeted LNP therapeutic strategies under the Cythera Bio platform.

6. Conclusion MNPs represent a modifiable environmental contributor to male infertility and prostate cancer risk. Interaction-mediated therapeutics provide a promising path beyond avoidance, complementing the broader portfolio on detection and mitigation.

Keywords: microplastics, nanoplastics, male fertility, spermatogenesis, prostate cancer, endocrine disruption, oxidative stress, interaction-mediated mitigation

Representative Citations

1. Zhang S, et al. Microplastics and nanoplastics in human semen and testicular tissue. Environ Int. 2023.

2. Park JH, et al. Polystyrene microplastics impair spermatogenesis and sperm quality in mice. Sci Total Environ. 2022.

3. Li Y, et al. Phthalates and bisphenol A as endocrine disruptors: effects on male reproductive function. Reprod Toxicol. 2021.

4. Hou B, et al. Microplastics induce oxidative stress and DNA damage in sperm cells. J Hazard Mater. 2024.

5. Zhao Q, et al. Nanoplastics cross the blood-testis barrier and alter testicular histology. Environ Sci Technol. 2023.

6. Herrala M, et al. Microplastic exposure and endocrine disruption in male reproductive tissues (NYU poster data). Environ Int. 2023 (presented 2025).