Effects of isoliquiritigenin on Notch signaling pathway in rats with cerebral ischemia-reperfusion injury

LIU Cheng; CHANG Lili; WANG Qiang; CHEN Liwei; QI Yawei; ZHANG Shijun

Abstract：Objective To explore the protective effects of isoliquiritigenin on cerebral ischemia-reperfusion injury and its molecular biological mechanism.Methods Different doses of isoliquiritigenin(0,10,20,40 and 80 μmol/L)were used to intervene rat neural stem cell C17.2,and the neural stem cell sphere-forming assay was carried out to compare the number of cell spheres.144 rats were established as rat models of cerebral ischemia-reperfusion and were randomly divided into 6 groups with 24 rats in each group,namely the control group,the cerebral ischemia-reperfusion injury group,the low-dose isoliquiritigenin treatment group,the middle-dose isoliquiritigenin treatment group,the high-dose isoliquiritigenin treatment group and positive control group(nimodipine).After 14 d of drug intervention,the cerebral infarction volume and cerebral water content in rats were detected.HE staining was used for cerebral pathological injury and neurodeficit score(NDS)system for neurological function detection.Flow cytometry and TUNEL staining were used to assess the cell apoptosis.ELISA was applied to detect the expression levels of interleukin 1β(IL-1β),tumor necrosis factor α(TNF-α)and IL-10 in cerebral tissues and chemical colorimetry was used to measure the contents of superoxide dismutase(SOD),malondialdehyde(MDA)and glutathione(GSH)in cerebral tissues.Western blot was used to detect the protein relative expressions of Notch1,Notch intracellular domain 1(NICD1)and Hes1.6 rats in the high-dose isoliquiritigenin treatment group were further given DAPT(Notch signaling pathway inhibitor)and detected by the same method as above.Results When the dose of isoliquiritigenin was 40 μmol·L-1 or 80 μmol·L-1,the number of C17.2 cell spheres increased significantly(P＜0.05).After intervention of middle and high doses of isoliquiritigenin,the volume of cerebral infarction in rats with cerebral ischemia-reperfusion was reduced,the NDS score was decreased,cerebral water content was lowered,the apoptosis rate of cerebral tissue was declined,the levels of IL-1β,TNF-α and MDA were reduced while the levels of IL-10,SOD and GSH were enhanced,and the protein expressions of Notch1,NICD1 and Hes1 in the middle-dose or high-dose isoliquiritigenin group were up-regulated compared with those in the cerebral ischemia-reperfusion group,and the above indicators in high-dose group were better than those in middle-dose group,and adding DAPT could reverse the above effects of high-dose isoliquiritigenin.Conclusions Isoliquiritigenin has protective effects on cerebral ischemia-reperfusion injury.Its role mechanism may be related to regulation of Notch signaling pathway.