The effect of midazolam on cerebral endothelial (P-selectin and ICAM-1) adhesion molecule expression during hypoxia-reperfusion injury in vitro

Background and objective: Hypoxia-reperfusion injury is an important determinant of secondary brain injury. In the acute phase of cerebral reperfusion, pro-inflammatory events enhance expression of cerebral endothelial (intercellular adhesion molecule-1 and P-selectin) adhesion molecules, which play an important role in brain hypoxia-reperfusion injury. Midazolam is the most commonly used sedative in patients with brain injury. The objective of this investigation was to examine the effect of midazolam on the expression of cerebral endothelial intercellular adhesion molecule-1 and P-selectin during hypoxia-reperfusion injury in vitro. Methods: The up-regulation of mouse cerebral endothelial cells intercellular adhesion molecule-1 and P-selectin was assessed following hypoxia-reoxygenation (hypoxia-reperfusion). Cells were pre-treated with three different concentrations of midazolam (0, 5 and 50 μg mL-1) prior to hypoxia. Flow cytometry was used to estimate adhesion molecule expression mean channel fluorescence. Data are presented as mean ± SD. Results: Mouse cerebral endothelial cell intercellular adhesion molecule-1 and P-selectin expression was greater after exposure to hypoxia-reoxygenation compared to normoxia (mean channel fluorescence) 241 ± 12 vs. 140 ± 7 and 120 ± 14 vs. 46 ± 7, respectively, P < 0.05. Intercellular adhesion molecule-1 and P-selectin expression was decreased by midazolam (5 μg mL-1) pre-incubation compared to control, mean channel fluorescence 184 ± 10 vs. 241 ± 12 and 51 ± 7 vs. 120 ± 14, respectively, P < 0.05. Midazolam at 50 μg mL-1 had the same effect as 5 μg mL-1. Conclusion: Pre-treatment with midazolam diminishes increased expression of cerebral endothelial intercellular adhesion molecule-1 and P-selectin expression following hypoxia-reoxygenation. © 2008 European Society of Anaesthesiology.