Effect of ischemic preconditioning on expression of intracellular adhesion molecule-1 in brain tissues following traumatic brain injury in rats

Objective To investigate the effect of ischemic preconditioning (IPC) on expression of intracellular adhesion molecule-1 (ICAM-1) in brain tissues following traumatic brain injury (TBI) in rats.Methods Sixty male SD rats weighing 220-250 g were randomly divided into three groups (n =20 for each):sham operation group,TBI group,and IPC group.Cerebral IPC models were induced by transient occlusion of the bilateral common carotid arteries; TBI models were induced by Feeney's freefalling method; rats in sham operation group were only performed exposure of dura of the right parietal lobe.Ten rats were sacrificed respectively at 6 and 72 hours after TBI and injured brain tissues were harvested to estimate wet/dry weight (W/D) ratio for the brain,determine ICAM-1 expression by immunohistochemistry and perform microscopic examination.Results Brain W/D ratio was significantly increased in TBI group compared with sham operation group (6 h:4.2 ± 0.4 vs 2.7 ± 0.4 ; 72 h:5.0 ±0.1 vs 3.1 ± 0.2,P ＜ 0.05).ICAM-1 expression was up-regulated in TBI group compared with sham operationgroup (6h:25.4±3.5vs8.6±1.3; 72 h:36.5±5.4 vs8.4±1.6,P＜0.05).W/D ratio was significantly decreased in IPC group compared with TBI group (6 h:3.5 ±0.6 vs 4.2 ±0.4; 72 h:3.7 ± 0.4 vs 5.0 ± 0.1,P ＜ 0.05).ICAM-1 expression was down-regulated in IPC group compared with TBI group (6 h:16.5 ± 2.7 vs 25.4 ± 3.5 ; 72 h:24.3 ± 4.6 vs 36.5 ± 5.4,P ＜ 0.05).Milder injury to brain tissues was observed in IPC group than in TBI group.Conclusion IPC can attenuate TBI in rats by down-regulating the expression of ICAM-1. Key words: Brain injuries;  Ischemic preconditioning;  Cell adhesion molecules