In situ perfusion with MCC950 modulates the pyroptosis-related axis and DAMP-TLR4 signaling in kidneys from...

Brain death (BD), followed by static cold storage (SCS), induces sterile inflammation in donor kidneys, leading to molecular injury that compromises graft quality. This response is associated with activation of the NLRP3 inflammasome and pyroptosis related pathways. We investigated whether pharmacological inhibition of NLRP3 with MCC950, administered during in situ renal perfusion, during SCS, or through a combined strategy, could attenuate BD-induced inflammation exacerbated by SCS. Male Wistar rats (n = 36) were subjected to BD followed by 6 h of donor maintenance and subsequent 16 h of SCS. MCC950 was delivered during in situ perfusion, added to the preservation solution, or administered using both approaches. Renal inflammation and injury were evaluated by gene expression analysis and histopathology. BD increased the expression of inflammasome and pyroptosis related genes (NLRP3, CASP1, GSDMD), mediators of DAMP-TLR4 signaling (HMGB1, TLR4, NF-κB) and apoptotic regulation (BCL2), with further amplification after SCS. In situ MCC950 administration markedly reduced the expression of inflammasome-related genes and downstream inflammatory signaling, whereas supplementation during SCS alone showed limited effects. Combined treatment enhanced suppression of selected mediators, including IL-18 and HMGB1. IL-1β expression and macrophage infiltration were not significantly altered. Overall, in situ renal perfusion with MCC950 attenuated BD and preservation-induced inflammation more effectively than inhibition restricted to SCS. These findings support targeted NLRP3 inhibition during donor management as a molecular preconditioning strategy that attenuates preservation-associated activation of inflammasome and pyroptosis related inflammatory signaling, with potential relevance for marginal kidneys.