Carnosic acid alleviated periodontitis by inhibiting ferroptosis via the Nrf2/GPX4 pathway.

BACKGROUND: Ferroptosis, caused by abnormal iron metabolism and lipid peroxidation, has been linked to pathogenic processes in several disorders. Its function and regulating mechanisms in periodontitis are still unclear, nevertheless. As a naturally derived phenolic diterpenoid molecule, carnosic acid (CA) serves multiple biological roles, including antioxidant, anti-inflammatory, and cytoprotective properties. Its potential for intervention in periodontitis and ferroptosis warrants further exploration. METHODS: In this investigation, we combined network pharmacology analysis with in vitro and in vivo experimental validation to systematically evaluate the mechanism of action of CA intervention in periodontitis. Through an intersectional analysis of drug targets, ferroptosis-related genes, and periodontitis-related genes, potential core targets were identified, and GO/KEGG enrichment analysis was performed. The results suggest that Nrf2 is at the core of the protein interaction network and is significantly enriched in antioxidant response and iron homeostasis regulation pathways. Subsequently, changes in ROS, MDA, GSH, SOD, Fe²⁺, and other indicators, as well as the expression of ferroptosis-related indicators (GPX4, SLC7A11, FTH1), were detected in LPS-induced RAW264.7 cell models and rat periodontal ligation models. The key role of Nrf2 was verified using the Nrf2-specific inhibitor ML385. RESULTS: Network pharmacology results indicate that ferroptosis is crucial in the potential mechanism of CA action on periodontitis. Nrf2 is the core regulatory molecule connecting CA, periodontitis, and ferroptosis. The experimental results revealed that CA dramatically lowered ROS and MDA levels in cells and periodontal tissues, inhibited the accumulation of Fe²⁺, elevated the contents of GSH and SOD, and GPX4, SLC7A11, and FTH1 expression. Mechanistic studies have found that CA restores the antioxidant and iron homeostasis regulatory system by activating the Nrf2/GPX4 signaling axis, thereby inhibiting the vicious cycle of ferroptosis. After Nrf2 was blocked by ML385, the anti-ferroptosis and anti-inflammatory effects of CA were significantly weakened. CONCLUSION: The current research is the first to elucidate that CA can alleviate periodontitis pathological damage by suppressing ferroptosis via activating the Nrf2/GPX4 signaling axis. This enriches the pharmacological action spectrum of CA and provides new targets and a theoretical basis for periodontitis intervention strategies based on ferroptosis regulation.