Transcranial direct current stimulation attenuates cerebral ischemia-reperfusion injury by inhibiting neuronal pyroptosis via Netrin-1

The significant role of pyroptosis in the early pathogenesis of ischemic stroke underscores the urgent need for effective management strategies. Transcranial direct current stimulation (tDCS), a noninvasive modality for modulating brain activity, has been shown to confer neuroprotection by inhibiting neuroinflammation during the acute phase of stroke. However, the specific mechanisms underlying the effect of tDCS on neuronal pyroptosis remain largely unexplored. We established brain I/R injury in adult male Sprague Dawley rats through a middle artery occlusion (MCAO) model. tDCS treatment began 24 h after MCAO and lasts for 6 consecutive days. Evaluate neurobehavioral deficits through an improved Neurological Severity Score (mNSS), Western blot, immunofluorescence staining, TUNEL staining, transmission electron microscopy (TEM), and enzyme-linked immunosorbent assay (ELISA) were used to evaluate the expression of pyroptosis related proteins, cell morphology, and levels of inflammatory factors. The results showed that tDCS markedly reduced the levels of NLRP3 inflammasome-dependent pyroptosis proteins (NLRP3, ASC, cleaved-Caspase-1, and GSDMD-N), accompanied by a reduction in the number of cell membrane perforation and cell death related to pyroptosis. Moreover, tDCS increased the expression of NTN-1, which inhibited the activation of NLRP3 inflammasome through the peroxisome proliferator-activated receptor gamma (PPAR-γ)/nuclear factor kappa-B (NF-κB) signaling pathway. Knockdown of NTN-1 reversed the anti-pyroptosis and neuroprotective effect of tDCS. In conclusion, tDCS exerted neuroprotection by curbing neuronal pyroptosis through the NTN-1-mediated PPAR-γ/NF- κB pathway, and could be a useful strategy for ischemic stroke recovery.