Silent brain infarction is a frequent complication of cardiac surgery and is associated with mood changes and cognitive disruption. Microsphere embolism (ME) rodent models recapitulate both the diffuse ischemic infarcts and the delayed subtle behavioral disturbances characteristic to silent infarction (SI). Previously, we have shown that ME leads to increased hippocampal inflammation, weakening of the blood brain barrier, and the infiltration of peripherally circulating inflammatory cells in rats. Given long-term increases in inflammatory activity following SI, the current study tests the efficacy of anti-inflammatory versus anti-depressant treatment strategies to reduce the inflammatory and behavioral sequelae of injury. Adult rats were administered either chronic meloxicam (preferential COX-2 inhibitor) or fluoxetine (SSRI) beginning five days prior to ME surgeries. After a two week recovery, animals were tested for anxiety-like behaviors in the open field paradigm and the hippocampus was examined for gene expression of inflammatory cytokines. Meloxicam treated animals showed a decrease in hippocampal gene expression of inflammatory markers (SPP1; p = 0.0272) and greater than a 3-fold change improvement in open field central tendency (p = 0.0003). No differences in inflammatory gene expression were observed in fluoxetine treated animals (SPP1; p = 0.3288); however, fluoxetine treatment resulted in a 2-fold change improvement in open field central tendency (p = 0.0138) suggesting that while both treatment strategies attenuate SI induced behavioral disruption, only meloxicam acts via inflammatory mechanisms. Given the long term negative consequences of increased central and peripheral inflammatory activity, the data suggest that anti-inflammatory therapeutic strategies may benefit patients at risk for SI as well as cardiac surgery candidates.
Anti-inflammatory activity of new amino acid derivatives
