Mechanism of Xumingtang in Gu Jin Lu Yan for Treatment of Ischemic Stroke Based on HIF-1α/NLRP3 Pathway-mediated Pyroptosis / 中国实验方剂学杂志

ABSTRACT

ObjectiveTo investigate the mechanism of Xumingtang in Gu Jin Lu Yan （《古今录验》） in regulating cell pyroptosis through the hypoxia-inducible factor-1α （HIF-1α）/NOD-like receptor pyrin domain-containing protein 3 （NLRP3） pathway in ischemic stroke （IS）. MethodSD rats were randomly divided into a sham operation group， a model group， low- and high-dose Xumingtang groups， and a metformin group， with 20 rats in each group. Oral administration was performed for 3 days， and tissue samples were collected. Differential messenger RNA （mRNA） was screened using high-throughput sequencing， and Gene Ontology （GO） and Kyoto Encyclopedia of Genes and Genomes （KEGG） pathway analyses were performed on key differentially expressed genes. The modified neurological severity score （mNSS） and 2，3，5-triphenyltetrazolium chloride （TTC） staining were used to evaluate the effect of brain infarction. Hematoxylin-eosin （HE） staining was used for pathological morphological observation of brain tissue. Enzyme-linked immunosorbent assay （ELISA） was used to compare the levels of interleukin-1β （IL-1β） and interleukin-18 （IL-18） in the ischemic cortical region. Double staining immunohistochemistry was used to detect the co-localization of HIF-1α and NLRP3. Real-time quantitative polymerase chain reaction （PCR） was performed to detect the mRNA expression of NLRP3， HIF-1α， Caspase-1 （CASP-1）， and gasdermin D （GSDMD）. Western blot was used to detect the protein expression of HIF-1α， NLRP3， CASP-1， and GSDMD. ResultA total of 5 705 differentially expressed genes （2 733 downregulated and 2 972 upregulated） were obtained by mRNA sequencing. After conversion to homologous genes and intersection with the pyroptosis gene set， 95 key differentially expressed pyroptosis genes were obtained. Compared with the sham operation group， the model group showed significantly increased mNSS scores， larger brain infarction areas （P<0.01）， diverse neuronal morphology， disordered arrangement， widened cell gaps， significantly increased levels of IL-1β and IL-18 in the ischemic cortical region （P<0.01）， enhanced co-localization fluorescence intensity， and significantly increased mRNA and protein expression levels of HIF-1α， NLRP3， CASP-1， and GSDMD （P<0.01）. Compared with the model group， the high-dose Xumingtang group showed the most significant improvement in neurological function scores and brain infarction areas （P<0.01）. The neuronal integrity and arrangement were more complete， and the cell gaps were narrower in all groups with drug treatment， with significantly reduced co-localization fluorescence intensity. Xumingtang could reduce the levels of IL-1β， IL-18， and the mRNA and protein expression of HIF-1α， NLRP3， CASP-1， and GSDMD （P<0.05， P<0.01）， with the high-dose Xumingtang group showing the most significant effect （P<0.01）. ConclusionXumingtang in Gu Jin Lu Yan can inhibit cell pyroptosis and promote neurological function recovery after IS， which may be related to the inhibition of the HIF-1α/NLRP3 pathway.