Blood-testis barrier-crossing extracellular vesicles for asthenozoospermia therapy via synergistic ATP replenishment and ferroptosis suppression.

Asthenozoospermia, a leading cause of male infertility characterized by impaired sperm motility, poses significant therapeutic challenges due to the restrictive blood-testis barrier (BTB). To address this limitation, we engineered multifunctional extracellular vesicles (EVs) derived from umbilical cord mesenchymal stem cells, loaded with adenosine triphosphate (ATP) to synergistically restore cellular bioenergetics and suppress ferroptosis. These EVs were further functionalized with an aggregation-induced emission luminogen for near-infrared-II (NIR-II) fluorescence imaging, enabling real-time visualization of their efficient BTB penetration and targeted accumulation within testicular tissues. Upon localization in the seminiferous tubules, the released ATP directly replenishes the energy reserves of spermatogenic cells and enhances sperm motility in asthenozoospermia models. Simultaneously, the EVs upregulate glutathione peroxidase 4, mitigating ferroptosis and synergizing with ATP to restore metabolic homeostasis. In vivo studies demonstrate the dual efficacy of this platform: the EVs precisely traverse the BTB while robustly inhibiting ferroptosis without systemic toxicity, significantly improving sperm count and kinematic parameters (motility, velocity). This study presents a multifunctional nanoplatform that integrates NIR-II-guided imaging, ATP-mediated energy restoration, and pathology-specific ferroptosis inhibition, providing a promising non-invasive therapeutic strategy for asthenozoospermia.