Lifestyle Modulation of Xenobiotic Stress: Aerobic Exercise Attenuates Nanoplastic-Associated Neuroendocrine Dysfunction via a Gut-Ovary-Brain Continuum.

Xenobiotic stress can disrupt neuroendocrine function, yet whether a modifiable lifestyle factor can alter internal burden and downstream toxicity remains unclear. Here, adult female zebrafish were exposed to polystyrene nanoplastics (NPs; 80 nm; 1.0 mg/L) for 21 days, with or without moderate aerobic exercise (AE; 12 cm/s, 20 min/day). NPs exposure alone caused significant ovarian accumulation of particle-like structures (TEM), elevated oxidative stress, increased follicular apoptosis (TUNEL), and disrupted reproductive hormones (E2, FSH, LH). It also induced anxiety- and depression-like behaviors in novel tank and shoaling tests, accompanied by elevated cortisol and altered monoamine (NE, 5-HIAA) levels. In contrast, concurrent AE markedly attenuated these effects: it reduced ovarian particle burden, improved antioxidant enzyme activities (SOD, POD), restored ovarian histoarchitecture, and normalized endocrine and neuroendocrine measures. These changes were supported by partial recovery of ovarian (ESR1, cyp19a1a, AMH) and brain (BDNF, TPH2) transcript levels. Gut microbiome profiling revealed that AE counteracted NPs-associated dysbiosis, enriching beneficial taxa, including Akkermansia and Lachnospiraceae_NK4A136_group. Predictive functional inference and correlation analyses linked these microbial shifts to enhanced fatty acid and tryptophan metabolic potential, which correlated with neuroendocrine recovery. Together, these data support a working model in which AE acts as an exposure modifier, coupling host physiology and microbiome-associated metabolic capacity to mitigate NPs-induced neuroendocrine dysfunction via a gut-ovary-brain continuum. Targeted metabolomics and causal microbiota perturbation will be needed to validate specific mediators.