Effects of different doses of dexmedetomidine on acute brain edema in mice with traumatic brain injury / 临床麻醉学杂志

ABSTRACT

Objective To explore the effects of different doses of dexmedetomidine on acute brain edema in mice with traumatic brain injury (TBI).Methods A total of 132 male C57BL/6J mice were randomly divided into six groupscontrol group (group C),sham-operation group (group Sham),traumatic brain injury group (group TBI),Dex 20 μg/kg (group D20),40 μg/kg (group D40),and 60 μg/kg (group D60),n=22 in each group.The TBI animal model was established by electric controlled cortical impactor (eCCI),then intraperitoneal injected by the administration of different doses of dexmedetomidine at 0,2 and 4 h after TBI.Twenty-four hours post-TBI,brain water content was measured by the dry-wet method,histological observation was performed using HE staining,and aquaporin 4 (AQP4) and NF-κB expression were detected using Western blot assay,respectively.Then,the modified neurological scale scores (mNSS) on 1,2,3,and 7 d and Morris water maze (MWM) test on 4,5,6 and 7 d post-TBI were used to evaluate the neurologic deficit of TBI mice.Results After traumatic brain injury,the mNSS scores,the escape latency,the brain water content and the expression of AQP4 and NF-κB increased significantly in group TBI (P＜0.01).Different doses of dexmedetomidine significantly reduced the mNSS scores,the escape latency,the brain water content and the expression of AQP4 and NF-κB (P ＜ 0.05 or P ＜ 0.01).And meanwhile dexrnedetomidine can lessen neuronal degeneration,and inflammation response.Additionally,the effect was remarkably in group D60 compared with group D20 (P ＜ 0.05 or P ＜ 0.01).Conclusion Dexmedetomidine can lessen brain edema and cognition impairment induced with traumatic brain injury,which is a dose-effect relationship within 20-60 μg/kg,and this effect may be related to the downregulation of AQP4 and NF-κB expression.