Lipopolysaccharide preconditioning induces neuroprotection against early brain injury after experimental subarachnoid hemorrhage.

Abstract

Subarachnoid hemorrhage (SAH) is a devastating neurological injury associated with significant morbidity and mortality. We postulated that lipopolysaccharide (LPS) preconditioning induces neuroprotection against early brain injury (EBI) after experimental SAH. 72 male Sprague-Dawley rats (250 to 300 g) were used. SAH was produced by injecting autologous arterial blood into the pre-chiasmatic cistern. Rats were given an intraperitoneal injection of LPS 24 hours prior SAH. Matrix metalloproteinase 9 (MMP-9) protein expression was measured by western blot; apoptosis in the cerebral cortex were studied by terminal deoxynucleotidyl transferasemediated deoxyuridine triphosphate-biotin nick-end labeling (TUNEL) and 4'6-diamidino-2-phenylindole dihydrochloride (DAPI) staining at 24 h after SAH. Brain water content was also examined. MMP-9 expression was increased after SAH and decreased by LPS preconditioning at 24 h after SAH. The number of neuronal death in cortex was increased after SAH and decreased by LPS preconditioning. In addition, brain water content was attenuated by LPS preconditioning. LPS preconditioning could modulate MMP-9 and therefore induce neuroprotection against EBI after experimental SAH.