The Mechanism of Baicalin in the Treatment of Mycoplasma Pneumoniae Pneumonia by Regulating NLRP3/Caspase-1 Signaling Pathway

This study investigated the mechanism of baicalin (BIA) attenuating the inflammatory response and lung injury in mycoplasma pneumoniae pneumonia (MPP) mice. MPP mouse models were established and then treated with BIA, azithromycin, or NLRP3 inflammasome activator. Lung wet-to-dry weight (W/D) ratio were weighed. Serum levels of MP-IgM, C-reactive protein (CRP) and bronchoalveolar lavage fluid (BALF) protein were detected by kits, NLRP3/Caspase-1 pathway-related protein levels by Western blot, and IL-1β, IL-18, IL-6 and TNF-α levels by ELISA. HE staining was performed to detect lung injury. MPP mice showed elevated mouse lung W/D ratio, upregulated serum MP-IgM and CRP levels and BALF protein, and enhanced IL-6 and TNF-α levels, which were reversed by BIA or azithromycin treatment, suggesting that BIA attenuated pulmonary inflammatory response in MPP mice. The lung tissue of MPP mice showed upregulated NLRP3, cleaved Caspase-1,Caspase-1, GSDMD-N and GSDMD levels and raised IL-1β and IL-18 levels, and changes were annulled by BIA or azithromycin treatment, suggesting that BIA inhibited the NLRP3/Caspase-1 pathway activation. NLRP3/Caspase-1 pathway activation partially abrogated the alleviative effect of BIA on the pulmonary inflammatory response of MPP mice. BIA mitigates inflammatory response and lung injury in MPP mice by inhibiting NLRP3/Caspase-1 pathway activation.