The Mechanism of Dexmedetomidine Regulating Autophagy-ROS-NLRP3 Pathway in Protecting Against Cerebral Ischemia-reperfusion Injury in Rats
LIU Kai
WANG Zhen
Abstract：Objective:To explore the effects and mechanisms of dexmedetomidine(DEX)on cerebral ischemia-reperfusion injury(CIRI)in rats.Methods:One hundred SD rats were randomly divided into the sham operation(Sham)group,the CIRI group,the autophagy inducer(RAPA)group,and the DEX+autophagy inhibitor(3-MA)group,with 20 rats in each group.Except for the Sham group,the other groups of rats were treated with wire clamping method to establish the rat model of middle cerebral artery CIRI.During reperfusion,rats in the DEX group were intraperitoneally injected with 100 μg/kg DEX immediately,rats in the RAPA group were intraperitoneally injected with 1 mg/kg RAPA immediately,and rats in the DEX+3-MA group were intraperitoneally injected with 100 μg/kg DEX and 15 mg/kg 3-MA immediately.Rats in the Sham and CIRI groups were intraperitoneally injected with the same volume of normal saline.Twenty-four hours after reperfusion,the neurological function impairment scores of the rats in each group were evaluated.The cerebral infarction rate were detected by the 2,3,5-triphenyltetrazolium chloride(TTC)method.The morphological structure of bain tissue was observated by hematoxylin-eosin(HE)staining.Terminal deoxyribonucleotidyl transferase(TdT)-mediated dUTP nick end labeling(TUNEL)staining was observated for detecting neuronal cell apoptosis.Autophagosome changes was observated by transmission electron microscopy.LC3 protein expression in neurons was analysed by immunofluorescence method.Western Blot was used to detect the expression of LC3 and NOD-like receptor protein 3(NLRP3)inflammasome-related proteins in brain tissue.The level of reactive oxygen species(ROS)in brain tissue was detected by the fluorescence method of dihydroethidium(DHE).Results:Compared with the Sham group,the brain tissue of rats in the CIRI group showed obvious pathological damage,the scores of neurological function impairment,the volume of cerebral infarction,and the rate of neuronal cell apoptosis increased(P＜0.05);the number of neuronal cell autophagosomes,the positive expression rate of LC3,the ratio of LC3-Ⅱ/LC3-Ⅰ in brain tissue,the expressions of NLRP3,ASC,Caspase-1,interleukin(IL)-1β,IL-18 proteins,and the ROS level upregulated(P＜0.05).Compared with the CIRI group,the brain tissue pathological damage in the DEX group and the RAPA group alleviated,and the scores of neurological dysfunction,the volume of cerebral infarction,and the rate of neuronal cell apoptosis decreased(P＜0.05);the number of neuronal cell autophagosomes,the positive expression rate of LC3,and the ratio of LC3-Ⅱ/LC3-Ⅰ in brain tissue increased(P＜0.05);the protein expressions of NLRP3,ASC,Caspase-1,IL-1β,IL-18 and the ROS level decreased(P＜0.05).Compared with the DEX group,the DEX+3-MA group were able to inhibit the changes in CIRI rat indicators caused by DEX(P＜0.05),and reverse the protective effect of DEX on CIRI.Conclusion:DEX can improve the neurological function in CIRI rats.The mechanism is related to inducing neuronal autophagy,reducing ROS levels,and inhibiting the activation of NLRP3 inflammasome.
Keywords：cerebral ischemia-reperfusion injurydexmetomidineautophagyNOD like receptor protein 3experimental study
Publication Date：2025-09-10
Online Publishing Date：2025-09-18(First online date of this platform, not the publication date of the document)
Pages：10( 2623-2632 )