Astaxanthin reduces type 2 diabetic‑associated cognitive decline in rats via activation of PI3K/Akt and attenuation of oxidative stress.

Abstract

Astaxanthin (AST) is an oxygenated derivative of carotenoid, which possesses a strong antioxidant activity. AST can effectively remove active oxygen from the body, and is thus considered to have an important role in disease prevention and treatment. The present study aimed to determine the effects of AST on type 2 diabetic‑associated cognitive decline (DACD) in rats. Rats were intraperitoneally injected with streptozotocin (STZ), in order to establish a model of diabetes mellitus (DM). A total of 40 rats were randomly divided into five groups: The control group, the DM group, the AST (50 mg/kg) group, the AST (100 mg/kg) group, and the AST+LY294002 group (AST, 50 mg/kg and LY, 0.25 µg/100 g). Following a 14‑day treatment with AST, the body weight, blood glucose levels and cognitive function were determined. In addition, the protein expression levels of phosphatidylinositol 3‑kinase (PI3K)/Akt, glutathione peroxidase and superoxide dismutase activity, glutathione and malondialdehyde content, and inducible nitric oxide synthase (iNOS), caspase‑3 and caspase‑9 activity were detected in the rats with DM. AST clearly augmented body weight and reduced blood glucose levels in rats with DM. Furthermore, treatment with AST significantly improved the cognitive function of rats with DM. Treatment with AST activated the PI3K/Akt pathway, and suppressed oxidative stress in the DM rats. In the cerebral cortex and hippocampus of the rats with DM, the activities of iNOS, caspase‑3 and caspase‑9 were markedly reduced. Furthermore, treatment with the Akt inhibitor LY294002 reduced the effectiveness of AST on DACD in rats. In conclusion, AST may reduce type 2 DACD in rats via activation of PI3K/Akt and attenuation of oxidative stress.