Protective effect of xanthoceraside against β-amyloid-induced neurotoxicity in neuroblastoma SH-SY5Y cells

Abstract

β-Amyloid (Aβ)-induced neurotoxicity is a major pathological mechanism of Alzheimer's disease (AD). Xanthoceraside, a triterpene extracted from the husk of Xanthoceras sorbifolia Bunge, has been shown to have therapeutic effects on learning and memory impairment induced by Aβ intracerebroventricular infusion in mice. In this study, we investigated the effect of xanthoceraside on the neurotoxicity of Aβ_25–35 in SH-SY5Y cells. Cell viability was measured by MTT (3-(3,4-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide) assay. Cell apoptosis, reactive oxygen species (ROS) generation, and mitochondrion membrane potential (MMP) were measured using Annexin V/propidium iodide, 2,7-dichlorofluorescein diacetate, and rhodamine 123 with flow cytometry, respectively. Intracellular calcium level was determined with Fura-2/AM. Caspase-3 activity in cell lysates was measured using the spectrophotometric method. Results indicated that pretreatment with xanthoceraside (0.01 and 0.1 μM) obviously increased the viability of SH-SY5Y cells injured by Aβ_25–35 in a dose-dependent manner. Aβ_25–35-induced early apoptosis, ROS overproduction, MMP dissipation, intracellular calcium overload, and increase in caspase-3 activity were markedly reversed by xanthoceraside. These findings suggested that xanthoceraside might be useful in the prevention and treatment of AD.

Keywords::

• xanthoceraside
• β-amyloid
• apoptosis
• oxidative stress
• mitochondrial dysfunction
• Alzheimer's disease

Acknowledgments

This work was financially supported by the research fund for the Doctoral Program of Higher Education (No. 20092134110007), National Science and Technology Major Special Project on Major New Drug Innovation (No. 2009ZX09103-119), and National Key Scientific Project for New Drug Discovery and Development of China (No. 2009ZX09301-012).