THE MECHANISM BY WHICH DEXMEDETOMIDINE ALLEVIATES EARLY BRAIN INJURY IN RATS WITH SUBARACHNOID HEMORRHAGE BY DOWN-REGULATING THE EXPRESSION OF NLRP3 INFLAMMASOME

Mingxin Ji, Peng Zhao, Yunfeng Cui, Xinyu Li^*

Department of Anesthesiology, The Second Hospital of Jilin University, Changchun, 130041, China

Objective: To investigate the mechanism by which dexmedetomidine alleviates early brain injury in rats with subarachnoid hemorrhage by down-regulating the expression of NLRP3 inflammasome. 

Method: 150 female SD rats were equally divided into 5 groups: healthy control group, model group, dexmedetomidine low-dose group, dexmedetomidine medium-dose group, and dexmedetomidine high-dose group. The submembrane hemorrhage was modeled, and the model group was given saline injection. Analysis was made on subarachnoid hemorrhage amount, brain water content, serum inflammatory factor levels, relative expression levels of NLRP3 and Caspase-1, microglia counts, and Bax, BCL-2, and TNFA expression levels of hippocampus in each group. The correlation between NLRP3 inflammasome and inflammatory factor levels was also analyzed. 

Results: The subarachnoid hemorrhage amount, brain water content, serum inflammatory factor levels, relative expression levels of NLRP3 and Caspase-1, microglia counts, and Bax, BCL-2, TNFA expression levels of hippocampus in each group were not statistically different before anesthesia (P>0.05), but showed statistical significance after anesthesia (P<0.05). With the increasing injection dose of dexmedetomidine, the levels of various inflammatory factors gradually decreased. Moreover, a positive correlation was shown between NLRP3 and IL-1β, TNF-α and IL-6 (P<0.05). 

Conclusion: Dexmedetomide can reduce the inflammatory response and NLRP3 level in rats by down-regulating the level of NLRP3 inflammasome, thereby lowering the degree of early brain injury in rats with subarachnoid hemorrhage.