Dihydromyricetin Alleviates Ischemic Brain Injury by Antagonizing Pyroptosis in Rats

Abstract

Ischemic stroke is a worldwide disease that seriously threatens human health, and there are few effective drugs to treat it. Dihydromyricetin (DHM) has anti-inflammatory, antioxidant, and antiapoptotic functions. We identified pyroptosis following ischemic stroke. Here, we investigated the effect of DHM on ischemic stroke and pyroptosis. In the first part of the experiment, Sprague-Dawley rats were randomly divided into the sham group and MCAO group. The MCAO model was established by occlusion of the middle cerebral artery for 90 min using a silica gel suture. The ischemic penumbra was used for mRNA sequencing 1 day after reperfusion. In the second part, rats were divided into the sham group, MCAO group, and DHM group. DHM was injected intraperitoneally at the same time as reperfusion starting 90 min after embolization for 7 consecutive days. The changes in pyroptosis were observed by morphological and molecular methods. The transcriptomics results suggested the presence of NLRP3-mediated pyroptotic death pathway activation after modeling. The Longa score was increased after MCAO and decreased after DHM treatment. 2,3,5-Triphenyltetrazolium chloride (TTC) staining showed that DHM could reduce the infarct volume induced by MCAO. Nissl staining showed disordered neuronal arrangement and few Nissl bodies in the MCAO group, but this effect was reversed by DHM treatment. Analysis of pyroptosis-related molecules showed that the MCAO group had serious pyroptosis, and DHM effectively reduced pyroptosis. Our results demonstrate that DHM has a neuroprotective effect on ischemic stroke that is at least partly achieved by reducing pyroptosis.