IMRC-Exo mitigates venom-induced limb injury in rabbits by inhibiting GSDME-dependent pyroptosis.

BACKGROUND

Inflammation plays a critical role in the pathogenesis of limb injury caused by snakebite. Investigating its regulatory mechanisms and intervention strategies may help identify effective treatments. Recent studies have shown that pyroptosis exacerbates organ damage by amplifying inflammatory responses. Additionally, immune and matrix-regulatory cells (IMRC), a novel type of mesenchymal stem cell, and their exosomes (Exo) have demonstrated potential in mitigating inflammation-mediated injury by suppressing pyroptosis. This study aimed to evaluate whether IMRC-Exo could alleviate venom-induced limb injury in rabbits by suppressing pyroptosis, thereby attenuating the associated inflammatory response.

METHODS

Eighteen healthy male New Zealand white rabbits were randomly assigned to Sham, Model, and IMRC-Exo groups. The Model group was established by intramuscular injection of venom (1.5 mg/kg), followed by intravenous snake antivenom (80 U/kg) after 2 hours. The IMRC-Exo group received IMRC-Exo (7.5 × 10 particles) post-modeling. Within 24 hours, left thigh circumference, serum creatine kinase (CK), and myoglobin (Mb) were assessed. Muscle tissues were collected for histopathology, apoptosis analysis, inflammatory cytokine quantification [high-mobility group box 1 (HMGB1), IL-1β, IL-18], and pyroptosis-related protein detection [caspase-3, cleaved caspase-3, gasdermin E (GSDME), N-terminal GSDME (N-GSDME)].

RESULTS

Compared to Sham, venom injection significantly increased thigh circumference, CK, Mb, histopathological damage, apoptosis, inflammatory cytokines, and pyroptosis-related proteins. IMRC-Exo significantly reduced these indicators, mitigating muscle injury and inflammation. Additionally, inflammatory cytokines and pyroptosis markers were significantly lower in the IMRC-Exo group than in the Model group.

CONCLUSION

IMRC-Exo effectively alleviates venom-induced limb injury in rabbits, likely through inhibition of GSDME-dependent pyroptosis-mediated inflammation. These findings suggest that IMRC-Exo may serve as a promising therapeutic approach for snakebite-induced inflammatory injury.