Matrine pre-intervention protects against inflammatory responses and mucosal injury in rats with gastric ulcer by inhibiting mitochondrial ferroptosis through the PKC/NOX4 pathway

Objective This study sought to investigate whether matrine (MAT) attenuates mitochondrial ferroptosis via the protein kinase C (PKC)/NADPH oxidase 4 (NOX4) pathway and to elucidate its role in inflammation and mucosal injury in the context of gastric ulcer (GU).Methods An ethanol/hydrochloric acid (EtOH/HCl)-induced GU rat model was established and pretreated with MAT, ferroptosis inducer Erastin, and PKC activator PMA, respectively. In vitro, EtOH-stimulated gastric mucosal epithelial cells (GES-1 and RGM-1) were pre-intervened with MAT in combination with Erastin or PKC modulators. Gastric injury, inflammatory cytokines, ferroptosis-related markers, levels of phosphorylated-protein kinase C (p-PKC), NOX4, and glutathione peroxidase 4 (GPX4) proteins, as well as mitochondrial function, were assessed using H&E staining, ELISA, biochemical assays, western blot, and functional analyses.Results EtOH/HCl-exposed GU rats showed increased ulcer index, reduced ulcer inhibition rate, along with elevated PKC phosphorylation, and interleukin-6, tumor necrosis factor-α, NOX4, malondialdehyde (MDA) and Fe2+ levels in gastric tissues, and decreased superoxide dismutase (SOD) activity, and GPX4 protein and glutathione levels. EtOH intervention resulted in consistent detrimental changes in GES-1/RGM-1 cells. Importantly, MAT pre-intervention markedly reversed these changes in both rat and cell models. Inhibition or silencing of PKC ameliorated mitochondrial dysfunction and ferroptosis in vitro. Moreover, Erastin or PMA administration/PKC overexpression averted the impacts of MAT pre-intervention on GU-associated rat inflammatory responses and GMI, or GES-1/RGM-1 cell mitochondrial dysfunction and ferroptosis.Conclusions MAT pre-intervention suppressed mitochondrial ferroptosis by inhibiting the PKC/NOX4 pathway, thereby protecting against GMI and inflammatory responses in the GU rat model.