Cryptotanshinone Inhibits Staphylococcus aureus-Induced Mastitis by Inhibiting Ferroptosis Through Activating Nrf2/GPX4 Pathway.

Mastitis is a prevalent gynecological disorder in women, with Staphylococcus aureus (S. aureus) serving as a primary etiological pathogen of this condition. Cryptotanshinone (CPT) has been demonstrated to exert anti-oxidative stress and anti-inflammatory effects, conferring therapeutic benefits for a diverse range of inflammatory diseases. However, its efficacy and underlying regulatory mechanisms in ameliorating S. aureus-induced mastitis remain elusive. Therefore, the present study was designed to elucidate the protective effects and molecular regulatory mechanisms of CPT against S. aureus-induced mastitis. A murine model of S. aureus-induced mastitis was established via intramammary injection of S. aureus, and CPT was administered to the model mice for therapeutic intervention. In vivo experiments revealed that CPT administration mitigated S. aureus-induced mastitis in mice by suppressing the production of pro-inflammatory cytokines and inhibiting ferroptosis. In vitro, CPT abrogated the S. aureus-induced elevation of TNF-α, IL-1β, MDA, ROS, and Fe2+ levels in mouse mammary epithelial cells (MMECs); additionally, it restored the ATP and GSH levels that were reduced by S. aureus stimulation in these cells. Furthermore, CPT concentration-dependently upregulated the expression of GPX4, Nrf2 and HO-1 in MMECs. Notably, the inhibitory effects of CPT on S. aureus-induced inflammatory responses and ferroptosis were abrogated in Nrf2-knockdown MMECs. In conclusion, this study demonstrates that CPT exerts a robust protective effect against S. aureus-induced mastitis by suppressing inflammatory responses and inhibiting ferroptosis through the activation of the Nrf2/GPX4 signaling pathway.