Xuebijing alleviates acute hydrogen sulfide-induced pyroptosis in rat spleen via suppression of the caspase-1/NLRP3 pathway.

Hydrogen sulfide (H2S) is a pervasive environmental toxicant with well-established immunotoxic effects. However, its action on lymphoid organs-particularly whether it triggers splenic pyroptosis-remains elusive. This study explored the effect of acute H2S exposure on rat spleen and the therapeutic potential of Xuebijing (XBJ), a traditional Chinese medicine for sepsis. Rats were exposed to 300 ppm H2S for 3 h, with or without 7-day XBJ pretreatment (4 mg/kg, i.p.). Splenic injury was evaluated by histopathology, ultrastructure, oxidative stress parameters, immunofluorescence, and immunoblotting. H2S exposure alone caused marked splenic damage, evidenced by increased organ coefficient, disrupted tissue architecture, mitochondrial swelling, and redox imbalance [depleted glutathione (GSH), superoxide dismutase (SOD), catalase (CAT); elevated malondialdehyde (MDA)]. Mechanistically, H2S activated the NF-κB/NLRP3/caspase-1 axis, upregulating NLRP3, ASC, cleaved caspase-1, and GSDMD-N, along with elevated interleukin-1β (IL-1β) and interleukin-18 (IL-18). XBJ pretreatment reversed these alterations, suppressing NF-κB phosphorylation, inflammasome assembly, and pyroptotic cell death. These findings demonstrate that H2S induces splenic pyroptosis via the NF-κB/NLRP3/caspase-1 pathway, and that XBJ confers protection by interrupting this cascade, offering a mechanism-based candidate for the treatment of acute H2S poisoning.