Saponins Attenuate Cerebral Ischemia-Reperfusion Injury via Mitophagy-Induced Inhibition of NLRP3 Inflammasome in Rats.

Background: The mitophagy/NLRP3 inflammasome pathway is a promising therapeutic target for cerebral ischemia-reperfusion (I/R). () F.H. Chen, one of the most valuable components of traditional Chinese medicine, and saponins (PNS), the main active ingredients of , are patent medicines commonly used to treat cardio- and cerebrovascular diseases. However, their effects on the mitophagy and the NLRP3 inflammasome activation in I/R remain unclear. Therefore, in this study, we investigated how PNS might affect the mitophagy/NLRP3 inflammasome pathway in I/R.

Methods: Cerebral I/R injury was induced by middle cerebral-artery occlusion, and expression levels of NLRP3 inflammasome signaling pathway-associated proteins were detected by western blot. We tested I/R injury using a neurological-deficit score, infarct volume, and hematoxylin and eosin staining, after which we detected both mitophagy- and NLRP3 inflammasome-related proteins in PNS-treated rats to determine whether PNS could attenuate I/R injury and the possible mechanisms involved.

Results: Our results showed that cerebral I/R could induce activation of the NLRP3 inflammasome, aggravating brain injury, whereas PNS effectively alleviated cerebral I/R injury in rats by inhibiting the NLRP3 inflammasome and promoting mitophagy via the PINK1/Parkin pathway. Moreover, mitophagy inhibited the NLRP3 inflammasome and mediated the anti-injury effects of PNS.

Conclusions: In conclusion, PNS could promote mitophagy via the PINK1/Parkin pathway by inhibiting activation of the NLRP3 inflammasome, alleviating cerebral I/R injury in rats.