6-Gingerol protects against cerebral ischemia/reperfusion injury by inhibiting NLRP3 inflammasome and apoptosis via TRPV1 / FAF1 complex dissociation-mediated autophagy

Background: Our previous studies demonstrated that Autophagy alleviates cerebral I/R injury by inhibiting NLRP3 inflammasome-mediated inflammation. 6-Gingerol, a phenolic compound extracted from ginger, was reported to possess potent antiapoptotic and anti-inflammatory activities and is associated with Autophagy. However, the effects of 6-Gingerol in cerebral I/R injury have not been elucidated, and whether they involve autophagy-induced NLRP3 inflammasome inhibition remains unclear.

Methods: Adult male Sprague-Dawley (SD) rats were subjected to middle cerebral artery occlusion (MCAO) for 1 h, followed by reperfusion for 24 h. 6-Gingerol and 3-methyladenine (3-MA) were injected intraperitoneally, and si-TRPV1 was injected via the lateral ventricle. Cerebral infarct volume, brain edema, neurological deficits, HE and Nissl were used to evaluate the morphological and functional changes of brain tissue, respectively. TRPV1, FAF1, Autophagy related (LC3II/I, p62, Beclin1), inflammation related (NLRP3, cleaved-caspase-1, Caspase-1, cleaved-IL-1β, IL-1β, cleaved-IL-18, IL-18) and Apoptosis related (Bcl-2, Bax, cleaved-caspase-3) proteins were assessed by Western blot, immunofluorescence staining and coimmunoprecipitation, respectively. Enzyme linked immunosorbent assay (ELISA) was used to evaluate the changes in the expression levels of interleukin-1 (IL-1β) and interleukin-18(IL-18), respectively. The degree of neuronal Apoptosis was evaluated by TUNEL staining. Neuronal ultrastructure was examined by transmission electron microscopy.

Result: 6-Gingerol treatment significantly reduced cerebral infarct volume, improved brain edema and neurological scores, and reversed brain histomorphological damage after I/R injury. In addition, 6-Gingerol significantly reduced NLRP3 inflammasome-derived inflammation and neuronal Apoptosis and upregulated Autophagy. The Autophagy Inhibitor 3-MA rescued the effects of 6-Gingerol on the NLRP3 inflammasome and Apoptosis. Moreover, the findings illustrated that 6-Gingerol inhibited autophagy-induced NLRP3 inflammasome activation and Apoptosis through the dissociation of TRPV1 from FAF1.

Conclusion: In brief, 6-Gingerol exerts antiapoptotic and anti-inflammatory effects via TRPV1/FAF1 complex dissociation-mediated Autophagy during cerebral I/R injury. Therefore, 6-Gingerol may be an effective drug for the treatment of I/R injury.