LSKL mitigates dehydroepiandrosterone-induced apoptosis and oxidative stress by THBS1/PI3K/AKT pathway in rat granulosa cells

Polycystic ovary syndrome (PCOS) is a common gynecological endocrine disorder characterized by abnormalities in the inflammation-like ovulatory process. Elevated thrombospondin-1 (THBS1) is associated with these disruptions, but the impact of Leu-Ser-Lys-Leu-NH₂ (LSKL), a THBS1 inhibitor, on PCOS-related abnormalities remains unclear. This study aims to explore the roles of THBS1 and LSKL in PCOS pathogenesis. PCOS were induced by administration of dehydroepiandrosterone (DHEA) to rats and granulosa cells (GCs) for 21 days. Thereafter, LSKL was administered to rats. Molecular docking was employed to assess the binding affinity between LSKL and THBS1. Cell viability, apoptosis, and reactive oxygen species (ROS) levels in GCs were evaluated using the Cell Counting Kit-8 (CCK8) assay and flow cytometry. In rats, parameters including body weight, estrous cycle, ovarian histopathology, serum hormone levels (luteinizing hormone, follicle-stimulating hormone, testosterone, estradiol), ovarian oxidative stress, and the expression of PI3K/AKT signaling and apoptosis-related proteins were analyzed. In vitro, molecular docking confirmed a strong binding affinity between LSKL and THBS1. LSKL alleviated DHEA-induced damage, reduced ROS accumulation, and inhibited apoptosis in dysfunctional GCs, while enhancing PI3K/AKT pathway activation. In vivo, LSKL mitigated ovarian injury and oxidative stress, restored estrous cycle regularity, normalized serum hormone levels, improved ovarian morphology (including reduced cystic dilation and follicular dysplasia), and suppressed ovarian apoptosis, all while boosting PI3K/AKT activity. These results position THBS1 as a potential therapeutic target for PCOS and demonstrate that LSKL mitigates ovarian damage, oxidative stress, and apoptosis in PCOS by inhibiting THBS1 and activating the PI3K/AKT pathway.