Edaravone neuroprotection effected by suppressing the gene expression of the Fas signal pathway following transient focal ischemia in rats

Preclinical and clinical studies have demonstrated that a free radical scavenger edaravone has neuroprotective effects on ischemic stroke but the underlying mechanism is not fully understood. The aim of this research is to explore the effect of edaravone on the apoptotic process involving the Fas/FasL signaling pathway. Transient focal ischemia in rats was induced for 2 hours by middle cerebral artery occlusion (MCAO). After reperfusion rats were treated i.v. with either edaravone or physiological saline. The expression of Fas-associated death domain protein (FADD), death-associated protein (Daxx) and caspase-8 was examined by immunohistochemistry. The mRNA levels for FADD and Daxx by reverse-transcriptase PCR (RT-PCR) and apoptosis was assessed by terminal deoxynucleotidyl-transferase-mediated dUTP-biotin nick end labeling (TUNEL). Neurological scores and infarction volumes were also evaluated. Edaravone significantly improved the neurological outcome (p < 0.05) and reduced the total infarct volumes (p < 0.05), compared with saline control. In addition, edaravone-treatment significantly reduced the number of TUNEL-positive cells (p < 0.01), reduced expression levels of FADD, Daxx and caspase-8 immunoreactivity (p < 0.05 similar to 0.01), and decreased mRNA levels of FADD and Daxx (p < 0.05 similar to 0.01) within the peri-infarct area. We conclude that edaravone may protect ischemic neurons from apoptosis via suppressing the gene expression of the Fas/FasL signaling pathway.