Background: Polycystic ovary syndrome (PCOS) is a prevalent endocrine disorder characterized by ovarian dysfunction. High mobility group box 1 (HMGB1) is elevated in PCOS and implicated in its pathogenesis, while nuclear factor E2-related factor 2 (Nrf2) is a key regulator of antioxidative defense. However, the role and mechanism of HMGB1 in PCOS, particularly its relationship with Nrf2 signaling in ovarian granulosa cell injury, remain unclear. This study aimed to investigate whether HMGB1 deficiency protects human ovarian granulosa cells from Dehydroepiandrosterone (DHEA)-induced impairments and to explore whether this protective effect is mediated through activation of the Nrf2 pathway.

Methods: In this work, a PCOS cellular model was established by treating KGN cells with 20 nM DHEA for 48 h. Then, si-HMGB1 or si-NC was transfected into KGN cells for loss-of-function experiments. To further elucidate the role of Nrf2 signaling in the HMGB1-mediated protective effect on ovarian cells, rescue experiments were performed wherein KGN cells underwent pretreatment with 10 μM Nrf2 inhibitor ML385 for 24 h before subsequent interventions.

Results: HMGB1 knockdown enhanced DHEA-treated KGN cells' impaired viability, as well as inhibited DHEA-induced ferroptosis and mitochondrial dysfunction of KGN cells (p < 0.05). ML385 treatment partially reversed the relieving impact of HMGB1 deficiency regarding impaired viability of ovarian granulosa cells (GCs) treated by DHEA, as well as inhibitory effects of HMGB1 deficiency on ferroptosis and mitochondrial dysfunction of ovarian GCs caused by DHEA induction (p < 0.05).

Conclusion: Deficiency of HMGB1 improves impaired viability of DHEA-treated GCs and suppresses ferroptosis and mitochondrial dysfunction in PCOS through Nrf2 activation.