Abstract 11502: Elevations in Proinflammatory Cytokines Il-1β and Il-12 in the Transgenic (mren2)27 Rat: A Clinically-Relevant Animal Model of Metabolic Syndrome

Abstract

Introduction: Spontaneous intracerebral hemorrhage (ICH) accounts for 10-15% of strokes and carries a 40% mortality rate within one month. Neuroinflammation plays a key role in secondary brain injury after ICH and inflammatory pathways may represent important therapeutic targets. A major obstacle in developing novel therapeutics is the lack of a translatable animal model that recapitulates the comorbidities of patient’s that suffer from ICH. Hypertension, diabetes, and obesity are components of the metabolic syndrome often seen in ICH patients, and may modulate the neuroinflammatory response to ICH. Thus, we aimed to characterize peripheral markers of systemic inflammation in a transgenic hypertensive (mRen2)27 rat model of metabolic syndrome. Methods: Serum proinflammatory cytokines IL-1β and IL-12 were measured using ELISA in naïve male and female (mRen2)27 (n=15) and healthy SD rats at 32 weeks of age (n=14). Systolic blood pressure (SBP) was measured by tail-cuff plethysmography. Statistical analyses of group differences were conducted using two-sample t-tests. Results: SBP (mm Hg) was significantly higher in the (mRen2)27 transgenic rats compared to SD rats, in both males (195 ± 4, n=8 vs. 125 ± 4, n=6, p< 0.05) and females (183±7, n=7 vs. 114±10, n=8, p< 0.05). Female (mRen2)27 rats had significantly higher serum concentrations (pg/mL) of IL-12 (1073±47, n=7 vs. 438±101, n=8, p< 0.05) and IL-1β (pg/mL) (11±3, n=7;. 4±1 , n=8, p< 0.05). Similarly, male (mRen2)27 rats had significantly higher levels of IL-12 compared to SD rats (825±58 , n=8 v. 582±90 , n=6, p< 0.05). IL-12 levels were higher in mRen female rats compared with males (1073±47, n=7 v. 825±58 , n=8, p< 0.05). Serum levels of IL-1β was not significantly different between male SD and (mRen2)27 rats. Conclusion: Compared to healthy SD rats, the pro-inflammatory cytokines IL-1β and IL-12 are elevated in a clinically-relevant animal model of spontaneous hypertension. These findings simulate human studies that have linked cardiometabolic disease with elevated levels of pro-inflammatory cytokines. Future studies using this animal model will seek to further characterize changes in perihematomal and peripheral levels of proinflammatory and inflammation-resolving cytokines following ICH.