DCAAA mitigates neuroinflammation and microglial pyroptosis in spinal cord injury by inhibiting PI3K/AKT/NF-κB and NLRP3/caspase-1/GSDMD signaling

Spinal cord injury (SCI) is a highly disabling condition affecting the central nervous system (CNS). In the context of secondary SCI, microglial pyroptosis exerts a profound influence on neurological recovery. A novel lipophilic unsaturated fatty acid derivative from Isatis indigotica, DCAAA, has been synthesized and its structure and toxicity were evaluated. Through extensive in vivo and in vitro studies, this study explored the therapeutic potential and underlying molecular mechanisms of DCAAA. Treatment with DCAAA markedly attenuated oxidative stress following SCI and suppressed the expression of pyroptosis-associated proteins NLRP3, GSDMD, ASC, and Caspase-1, along with pro-inflammatory cytokines IL-1(3 and IL-18. Histological analyses, including HE, Nissl, and Masson staining, alongside Basso-Beattie-Bresnahan (BBB) scoring and footprint analysis, demonstrated that DCAAA facilitated axonal regeneration and improved motor function post-SCI. In vitro experiments, simulating pyroptosis through lipopolysaccharide (LPS) and adenosine triphosphate (ATP) exposure, yielded findings consistent with those observed in vivo. DCAAA significantly mitigated BV2 cell activation and oxidative stress following stimulation, while inhibiting the expression of pyroptosis-related proteins and pro-inflammatory cytokines. In conclusion, DCAAA reduces microglial pyroptosis following SCI by targeting the PI3K/AKT/NF-kappa B and NLRP3/caspase-1/GSDMD pathways, thereby promoting axonal regeneration and enhancing motor function recovery.