Microplastics and nanoplastics in follicular fluid are associated with diminished ovarian reserve: clinical and molecular insights.
Level 4 - case-series / case-control
Case-control study in humans combined with preclinical animal and in vitro models
PubMed 41592677 · doi:10.1016/j.jare.2026.01.074
What was done
Follicular fluid microplastics and nanoplastics (MNPs) were analyzed in 110 patients with diminished ovarian reserve (DOR) and 110 age-matched controls. Researchers also established a mouse MNP-exposure model to assess ovarian morphology, hormone levels, estrous cyclicity, intestinal barrier integrity, and gut microbiome changes via metagenomic sequencing. The therapeutic potential of oral *Parabacteroides goldsteinii* was tested in the mice. In vitro, a human granulosa cell line was treated with MNPs for 48 hours to examine transcriptomic alterations in the PI3K/AKT/mTOR pathway.
What was found
Multiple MNPs were identified in human follicular fluid, with polyamide 66 significantly associated with DOR, and higher concentrations of polystyrene and polyvinyl chloride observed in DOR patients compared to controls (no numerical concentrations, effect sizes, or p-values were reported in the abstract). In mice, MNP exposure caused disrupted estrous cycles, increased atretic follicles, hormonal imbalances, intestinal barrier damage, and reduced abundance of *P. goldsteinii* and its metabolite 7-keto-lithocholic acid (7-keto-LCA). Supplementation with *P. goldsteinii* reversed these DOR-like changes and restored 7-keto-LCA levels. In human granulosa cells, MNPs altered PI3K/AKT/mTOR signaling.
Why it matters
This study provides initial clinical and translational evidence linking follicular plastic exposure to reduced ovarian reserve, proposing a gut-ovary axis mechanism and potential microbial targets.
Limits
The abstract reports no numerical data, confidence intervals, or precise effect estimates for human MNP concentrations. The human component is an observational case-control study, which cannot prove causality or rule out confounding exposures. The rescue effect of *P. goldsteinii* was demonstrated only in mice and cannot be directly translated to human clinical efficacy without randomized trials.