Resveratrol promotes axonal regeneration via PI3K/Akt pathway in rats after intracerebral hemorrhage

Abstract

Objective To investigate the mechanism by which resveratrol (RES) promotes axonal regeneration in rats after intracerebral hemorrhage (ICH) and explore the role of the PI3K/Akt pathway that regulates the AMPKα pathway. Methods A total of 126 male adult SD rats were randomized into sham- operated group (n=30), ICH group (n=30), low-dose (20 mg/kg) RES group (n=30), high-dose (40 mg/kg) RES group and PI3K/Akt inhibitor (LY294002) group (n=6). Rat models of ICH were established by stereotaxic injection of autologous blood into the basal ganglia with subsequent treatments as indicated. The neurological deficits of the rats were evaluated, and the pathological changes in the brain tissues were observed with HE staining. The parameters of oxidative stress in each group were detected using ELISA. Western blotting, immunohistochemistry and immunofluorescence assay were performed to detect the expressions of neurofilament 200 (NF200), microtubule-associated protein-2 (MAP-2), myelin basic protein (MBP), growth-associated protein 43 (GAP43), protein kinase B (PKB or Akt), AMP-activated protein kinase alpha (AMPKα) and glycogen synthase kinase 3 beta (GSK-3β) in the brain tissue. Results The rats exhibited significant neurological deficits, obvious brain pathologies, and elevated oxidative stress level following ICH. Intervention with RES, especially at the high dose, obviously alleviated the injuries of the brain tissue. Western blotting and immunohistochemistry showed that compared with those in ICH group, the expression of NF200 and MAP-2 increased significantly in the hemorrhagic region in rats receiving RES treatment, and the effect was more obvious in the high-dose group than in the low-dose group (P < 0.05). Immunofluorescence assay showed that RES treatment of the rats, especially at the high dose, obviously enhanced MBP expression in the brain tissue as compared with that in ICH group (P < 0.05), and AMPK was found to mediate the effect of RES on the axons. The results of Western blotting further confirmed that RES treatment significantly decreased the expressions of p-AMPKα and p-GSK-3β and increased the expressions of NF200, MAP-2, MBP, GAP43 and p-Akt in the hemorrhagic brain tissues of the rats, as compared with those in ICH group, and high-dose RES produced significantly stronger effects on these proteins (P < 0.05). These effects of RES were obviously reversed by the application of PI3K/Akt inhibitor in the rat models of ICH. Conclusion RES can promote axonal regeneration and neurological function recovery in rats after ICH possibly by down-regulating the AMPK pathway through the PI3K/Akt pathway.

Keywords

• resveratrol
• intracerebral hemorrhage
• axons
• pi3k/akt
• ampk