Effects of dexmedetomidine on cognitive function and hippocampus P2X7 expression in rats with traumatic brain injury

ZHENG Bin; ZHANG Shun-cai; ZENG Yan-ru; LI Ping; FU Xiao-dong; RUAN Xiang-cai; XU Li-xin; SHE Shou-zhang

Abstract：Objective To observe the effects of Dexmedetomidine ( Dex) on cognitive function and neuroinflam-mation after traumatic brain injury (TBI), and to discuss the possible mechanism of P2X7 receptor in these effects. Methods Eighty Male SD rats (3~4 months old) were randomly divided into control group , Dex group, TBI group, and TBI+Dex group (n=20).The TBI model was established.Intraperitoneal Dex (20μg· kg-1) was given to the subjects in Dex group and TBI+Dex group , while saline was given in control group and TBI group .Moris water maze test was per-formed to evaluate the cognitive function 6 days after TBI .ELISA was used to quantify the concentration of interleukin -1β(IL-1β) in hippocampus.Western blot was used to measure the expression of P 2X7 in hippocampus.Results Compared with control group , the escape latency was significantly prolonged , with the time of staying at the original plat-form quadrant shortened, between Day 3 and 5 in TBI group (P<0.05);meanwhile, the concentration of IL -1β, and the expression of P2X7 in hippocampus were significantly increased in TBI group ( P <0.001).Compared with TBI group, the escape latency was significantly shortened , with the time of staying at the original platform quadrant prolonged in TBI+Dex group (P<0.05); meanwhile, the concentration of IL -1β, and the expression of P2X7 in hippocampus were significantly reduced in TBI +Dex group (P<0.001).Conclusion Dexmedetomidine can attenuate TBI -induced cognitive decline and neuroinflammation via inhibiting the activity of P 2X7 receptor.