Isoastilbin inhibits neuronal apoptosis and oxidative stress in a rat model of ischemia-reperfusion injury in the brain: Involvement of SIRT1/3/6

Background. Isoastilbin (IAB) has been shown to have antioxidative and anti-apoptotic functions. A recent study found that IAB can reduce oxidative stress in Alzheimer's disease. However, whether the antioxidative function of IAB is also protective in other brain diseases remains unknown. Objectives. To investigate the roles and underlying mechanisms of IAB in middle cerebral artery occlusionreperfusion (MCAO/R) in rats. Materials and methods. Male Wistar rats were randomly divided into 5 groups: sham group, MCAO/R group, and 3 MCAO/R groups groups administered IAB (20 mg/kg, 40 mg/kg or 80 mg/kg) once a day for 3 days. Infarction size, modified Neurological Severity Score (mNSS), oxidative stress markers, and neuronal apoptosis markers were used to assay the function of IAB. Results. Compared with the MCAO/R group, administration of IAB reduced the infarction size and mNSS scores in MCAO/R rats. Isoastilbin also decreased the level of malondialdehyde (MDA) and enhanced the activity of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX). Isoastilbin treatment attenuated MCAO/R-induced neuronal apoptosis compared with the MCAO/R group, as indicated by the results of terminal deoxynucleotide transferase-mediated X-dUTP nick end (TUNEL) and western blot assays. Isoastilbin also reversed MCAO/R-induced downregulation of SIRT1/3/6 protein expression. Conclusions. These observations suggest that IAB protects against oxidative stress and neuronal apoptosis in rats following cerebral ischemia-reperfusion (I/R) injury through the upregulation of SIRT1/3/6, indicating that IAB might be a promising therapeutic agent for cerebral I/R injury.