Abstract WP255: The Novel C-Jun N-terminal Kinase Inhibitor IQ-1S Protects Against Cerebral Ischemia-reperfusion Injury In Mice

Abstract

The c-Jun N-terminal kinase (JNK) has been shown to be an important regulator of neuronal cell death. Recently, we synthesized the sodium salt of 11H-indeno[1,2-b]quinoxalin-11-one (IQ-1S) and demonstrated it was a high-affinity inhibitor of the JNK family, with preference for JNK3. We hypothesized that IQ-S1 could decrease stroke vulnerability in vivo by altering JNK activity, apoptosis, and inflammation. To test our hypothesis, we subjected wild-type (C57BL6, male, 8-12 weeks old) mice to a stroke model of temporal focal ischemia (30 minutes) with subsequent reperfusion (48 hours). The mice were anesthetized with 1.5 % of aerrane in 30% oxygen/70% nitrous oxide, and body temperature was maintained at 36.5-37.0° C. Mice were treated intraperitoneally with IQ-1S (25 mg/kg) suspended in 10% solutol (100 μl) or with vehicle alone (10% solutol, 100 μl) 30 minutes before and 12 and 24 hours after middle cerebral artery occlusion (MCAO). Using laser-Doppler flowmetry, we monitored cerebral blood flow (CBF) above the middle cerebral artery during 30 minutes of MCAO provoked by a filament and during the first 30 minutes of subsequent reperfusion. In mice treated with IQ-S1, ischemic and reperfusion values of CBF were not different from vehicle-treated mice. However, IQ-S1 treated mice demonstrated markedly reduced infarct volumes (35 ± 23 mm3, n=6; Mean ± SD, standard tetrazolium staining) when compared with vehicle-treated mice (68 ± 23 mm3, n=5, p< 0.05) after 48 hours of reperfusion. Neurological deficit after 48 hours of reperfusion was improved in IQ-S1 treated mice (1.0 point deficit on a 5 point scale) as compared with vehicle treated mice (1.8 point deficit). Our results indicate that the novel JNK inhibitor improved stroke outcome in a mouse model of cerebral reperfusion. We conclude that IQ-S1 can serve as specific small-molecule modulator for mechanistic studies of JNK function in cerebral ischemia and reperfusion injury.