Diosmetin Alleviates MRSA-Induced Pneumonia in Mice by Inhibiting NLRP3 Inflammasome Activation and NF-κB Signaling Pathway

Background/Objectives: Methicillin-resistant Staphylococcus aureus (MRSA) is a multidrug-resistant pathogen that poses a major public health concern. It predominantly infects immunocompromised individuals and is frequently associated with severe pulmonary complications, including acute lung injury. Diosmetin, a natural flavonoid, known for its anti-inflammatory, antioxidant, and anti-infective properties. Nevertheless, its therapeutic mechanism in the treatment of acute pneumonia induced by MRSA remains unclear. Methods: In this study, we employed network pharmacology and molecular docking to elucidate the mechanisms underlying the therapeutic effect of diosmetin against MRSA-induced pneumonia. An MRSA pneumonia model was established in Balb/c mice. The impacts of diosmetin on murine pneumonia were evaluated by detecting biochemical indicators via HE staining, ELISA, RT-qPCR, and WB. In vitro experiments utilized RAW264.7 macrophages to establish an MRSA infection model for further validation of the therapeutic mechanisms of diosmetin. Results: In vivo results demonstrated that diosmetin alleviated MRSA-induced lung injury and reduced mortality by inhibiting the release of pro-inflammatory cytokines. Furthermore, compared with model mice, diosmetin-treated mice showed reduced phosphorylation levels of NLRP3, pro-caspase-1, ASC, and NF-κB p65, along with an increased level of IκBα in lung tissue. In vitro experiments indicated that diosmetin effectively reduced the levels of pro-inflammatory cytokines in MRSA-infected RAW264.7 macrophages and exerted anti-inflammatory effects by modulating the expression of NLRP3, pro-caspase-1, ASC, IκBα, and NF-κB p65. Conclusions: Our results demonstrate that diosmetin alleviates MRSA-induced pneumonia in mice, and this protective effect is achieved through dual inhibition of the NF-κB/NLRP3 inflammasome axis.