Size-dependent Deleterious Effects of Nano- and Microplastics on Sperm Motility.
Toxicology 2024:153834. [PMID:
38763425 DOI:
10.1016/j.tox.2024.153834]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 04/30/2024] [Accepted: 05/15/2024] [Indexed: 05/21/2024]
Abstract
INTRODUCTION
Growing concerns regarding the reproductive toxicity associated with daily life exposure to micro-/nano-plastics (abbreviated as MNPs) have become increasingly prevalent. In reality, MNPs exposure involves a heterogeneous mixture of MNPs of different sizes rather than a single size.
METHODS
In this study, an oral exposure mouse model was used to evaluate the effects of MNPs of four size ranges: 25-30nm, 1-5µm, 20-27µm, and 125-150µm. Adult male C57BL/6J mice were administered environmentally relevant concentrations of 0.1mg MNPs/day for 21 days. After that, open field test and computer assisted sperm assessment (CASA) were conducted. Immunohistochemical analyses of organ and cell type localization of MNPs were evaluated. Testicular transcriptome analysis was carried out to understand the molecular mechanisms.
RESULTS
Our result showed that MNPs of different size ranges all impaired sperm motility, with a decrease in progressive sperm motility, linearity and straight-line velocity of sperm movement. Alterations did not manifest in animal locomotion, body weight, or sperm count. Noteworthy effects were most pronounced in the smaller MNPs size ranges (25-30nm and 1-5µm). Linear regression analysis substantiated a negative correlation between the size of MNPs and sperm curvilinear activity. Immunohistochemical analysis unveiled the intrusions of 1-5µm MNPs, but not 20-27µm and 125-150µm MNPs, into Leydig cells and testicular macrophages. Further testicular transcriptomic analysis revealed perturbations in pathways related to spermatogenesis, oxidative stress, and inflammation. Particularly within the 1-5µm MNPs group, a heightened perturbation in pathways linked to spermatogenesis and oxidative stress was observed.
CONCLUSIONS
Our data support the size-dependent impairment of MNPs on sperm functionality, underscoring the pressing need for apprehensions about and interventions against the escalation of environmental micro-/nano-plastics contamination. This urgency is especially pertinent to small-sized MNPs.
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