T-lymphocytes promote cerebral inflammation, thus aggravating neuronal injury after stroke. Fingolimod, a sphingosine 1-phosphate receptor analog, prevents the egress of lymphocytes from primary and secondary lymphoid organs. Based on these findings, we hypothesized fingolimod treatment would reduce the number of T-lymphocytes migrating into the brain, thereby ameliorating cerebral inflammation following experimental intracerebral hemorrhage (ICH). We investigated the effects of fingolimod in two well-established murine models of ICH, implementing intrastriatal infusions of either bacterial collagenase (cICH) or autologous blood (bICH). Furthermore, we tested the long term neurological improvements by Fingolimod in a collagenase-induced rat model of ICH. Fingolimod, in contrast to vehicle administration alone, improved neurological functions and reduced brain edema at 24 and 72 hours following experimental ICH in CD-1 mice (n=103; p<0.05). Significantly fewer lymphocytes were found in blood and brain samples of treated animals when compared to the vehicle group (p<0.05). Moreover, fingolimod treatment significantly reduced the expression of intercellular adhesion molecule-1 (ICAM-1), interferon-γ (INF-γ), and interleukin-17 (IL-17) in the mouse brain at 72 hours post-cICH (p<0.05 compared to vehicle). Long-term neurocognitive performance and histopathological analysis were evaluated in Sprague-Dawley rats between 8 and 10 weeks post-cICH (n=28). Treated rats showed reduced spatial and motor learning deficits, along with significantly reduced brain atrophy and neuronal cell loss within the basal ganglia (p<0.05 compared to vehicle). We conclude that fingolimod treatment ameliorated cerebral inflammation, at least to some extent, by reducing the availability and subsequent brain infiltration of T-lymphocytes, which improved the short and long-term sequelae after experimental ICH in rodents.

Germinal matrix hemorrhage (GMH) is the most common neurological disease of premature newborns. GMH causes neurological sequelae such as cerebral palsy, post-hemorrhagic hydrocephalus, and mental retardation. Despite this, there is no standardized animal model of spontaneous GMH using newborn rats to depict the condition. We asked whether stereotactic injection of collagenase type VII (0.3 U) into the ganglionic eminence of neonatal rats would reproduce the acute brain injury, gliosis, hydrocephalus, periventricular leukomalacia, and attendant neurological consequences found in humans. To test this hypothesis, we used our neonatal rat model of collagenase-induced GMH in P7 pups, and found that the levels of free-radical adducts (nitrotyrosine and 4-hyroxynonenal), proliferation (mammalian target of rapamycin), inflammation (COX-2), blood components (hemoglobin and thrombin), and gliosis (vitronectin and GFAP) were higher in the forebrain of GMH pups, than in controls. Neurobehavioral testing showed that pups with GMH had developmental delay, and the juvenile animals had significant cognitive and motor disability, suggesting clinical relevance of the model. There was also evidence of white-matter reduction, ventricular dilation, and brain atrophy in the GMH animals. This study highlights an instructive animal model of the neurological consequences after germinal matrix hemorrhage, with evidence of brain injuries that can be used to evaluate strategies in the prevention and treatment of post-hemorrhagic complications.

Background and Purpose We examined effects of isoflurane, volatile anesthetics, on blood-brain barrier (BBB) disruption in the endovascular perforation model of subarachnoid hemorrhage (SAH) in mice. Methods Animals were assigned to sham-operated, SAH+vehicle-air, SAH+1% or 2% isoflurane groups. Neurobehavioral function, brain water content, Evans blue dye extravasation and Western blotting for sphingosine kinases (SphKs), occludin, claudin-5, junctional adhesion molecule and vascular endothelial cadherin were evaluated at 24 hours post-SAH. Effects of SphK (DMS) or sphingosine-1-phosphate receptor-1/3 (S1P1/3) inhibitors (VPC23019) on isoflurane's action were also examined. Results SAH aggravated neurological scores, brain edema and BBB permeability, which were prevented by 2% but not 1% isoflurane posttreatment. 2% isoflurane increased SphK1 expression and prevented a post-SAH decrease in expressions of the BBB-related proteins. Both DMS and VPC23019 abolished the beneficial effects of isoflurane. Conclusions 2% isoflurane can suppress post-SAH BBB disruption, which may be mediated by SphK1 expression and S1P1/3 activation.

The study of apoptosis in EBI after experimental SAH may give us new therapies for SAH.

Background and Purpose Perihematomal edema formation and consequent cell death contribute to the delayed brain injury evoked by intracerebral hemorrhage (ICH). In this study we aimed to evaluate the effect of α7 nicotinic acetylcholine receptor (α7nAChR) stimulation, on behavior, brain edema and neuronal apoptosis. Furthermore we aimed to determine the role of the pro-apoptotic glycogen synthase kinase-3β (GSK-3β) after experimental ICH. Methods Male CD-1 mice (n=109) were subjected to intracerebral infusion of autologous blood (n=88) or sham surgery (n=21). ICH animals received either vehicle administration, 4 or 12 mg/kg of α7nAChR agonist PHA-543613, 12 mg/kg of α7nAChR agonist PNU-282987, 6 mg/kg of α7nAChR antagonist methyllycaconitine (MLA), 15 μg/kg of phosphatidylinositol 3-kinase (PI3K) inhibitor wortmannin or PHA-543613 combined with MLA or wortmannin. Behavioral deficits and brain water content were evaluated at 24 and 72 hours after surgery. Western blotting and immunofluorescence staining were utilized for the quantification and localization of activated Akt (p-Akt), GSK-3β (p-GSK-3β) and cleaved caspase-3 (CC3). Neuronal cell death was quantified via terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL). Results α7nAChR stimulation improved neurological outcome and reduced brain edema at 24 and 72 hours after surgery (p<0.05 compared to vehicle). Furthermore, PHA-543613 treatment increased p-Akt and decreased p-GSK-3β and CC3 expressions in the ipsilateral hemisphere (p<0.05, respectively), which was reversed by MLA and wortmannin. P-Akt, p-GSK-3β and CC3 were generally localized in neurons. PHA-543613 reduced neuronal cell death in the perihematomal area (p<0.05). Conclusion α7nAChR stimulation improved functional and morphological outcomes after experimental ICH in mice. PHA-543613 reduced the expression of pro-apoptotic GSK-3β via the PI3K-Akt signaling pathway.