Effect of COX-2 protein expression on learning and memory function after severe traumatic brain injury in rats

AIM:To observe the expression of COX-2 and the effect of the selective COX-2 inhibitor NS-398 on learning and memory function of rats after traumatic brain injury(TBI).METHODS:The model of severe closed TBI was established according to the method created by Marmarou.Adult Wistar rats(n=360)were randomly divided into TBI group,NS-398 treatment group,and sham operation group,and each of them was sub-divided into post-traumatic 1,3,6,12,24,48,72,96,168 and 336 h groups.Another 120 rats were taken as normal controls.The NS-398 treatment group after injury was treated with NS-398 [40 mg/(kg·d)] ip.The TBI group,the sham operation group,and the control group were treated with normal saline.All rats were killed at each time point,for detecting COX-2 protein expression with Western Blot and immunohistochemistry.Another 24 rats were randomly divided into TBI group,NS-398 treatment group,sham operation group,and normal group.The cognitive dysfunction was evaluated using the Morris water maze(MWM).RESULTS:NS-398 could apparently down-regulate the peak of COX-2 protein expression in brain and obviously shorten the latency of Morris water maze tests.CONCLUSION:COX-2 is correlated with secondary brain injury induced by TBI,and NS-398 may effectively improve cognitive dysfunction after TBI.