Effect of midazolam on in vitro cerebral endothelial ICAM-1 expression induced by astrocyte-conditioned medium.
OBJECTIVE
Astrocytes exposed to hypoxia produce pro-inflammatory cytokines and upregulate intercellular adhesion molecule-1 on cerebral endothelium. This study investigated the effects of midazolam on this response.


METHODS
Mouse astrocytes were exposed to 4 h of hypoxia and 24 h of reoxygenation. Astrocyte-conditioned medium were applied to mouse cerebral endothelial cell cultures for 4 h and 24 h in normoxia. Endothelial cells were pre-incubated for 1 h with midazolam (0, 5, 50 microg L-1). Flow cytometry was used to estimate endothelial ICAM-1 expression. IL-1beta concentrations were measured with ELISA. Repeated comparisons were made using ANOVA and post hoc Tukey Test as appropriate. Data are mean (SD).


RESULTS
Mouse cerebral endothelial cell ICAM-1 expression was greater after 24 h exposure to hypoxia-reoxygenation astrocyte-conditioned medium compared to normoxic astrocyte-conditioned medium (mean channel flouresence 112.5 (9.5) vs. 81.5 (7.5), P = 0.01). ICAM-1 expression was decreased by midazolam (5 microg L(-1)) compared to control (mean channel flouresence 81.35 (7.5) vs. 112.5 (9.5), P = 0.01). Supernatant IL-1beta concentrations (pg mL(1)) in astrocytes exposed to hypoxia-reoxygenation were greater than those exposed to normoxia (16.41 (2.35) vs. 10.5 (2.13), P = 0.01).


CONCLUSIONS
We conclude that decreased cerebral endothelial ICAM-1 expression in response to activated glial cell compartment by midazolam may decrease post ischaemic brain inflammation and secondary brain injury.
Ghori
K
K
Cork University Hospital and University College Cork, Department of Anaesthesia and Intensive Care Medicine, Cork, Ireland.
Harmon
D
D
Walsh
F
F
Shorten
G
G
D018686:Anesthetics, Intravenous / Q000494:pharmacology*; D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D017077:Culture Media, Conditioned / Q000494:pharmacology*; D042783:Endothelial Cells / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D000860:Hypoxia; D007249:Inflammation; D018799:Intercellular Adhesion Molecule-1 / Q000096:biosynthesis* / Q000378:metabolism; D053583:Interleukin-1beta / Q000378:metabolism; D051379:Mice; D008874:Midazolam / Q000494:pharmacology*; D013687:Telencephalon / Q000473:pathology
D018686:Anesthetics, Intravenous; D017077:Culture Media, Conditioned; D053583:Interleukin-1beta; D018799:Intercellular Adhesion Molecule-1; D008874:Midazolam