Abstract
Alzheimer's disease (AD) brains demonstrate decreased levels of brain-derived neurotrophic factor (BDNF) and increased levels of β-amyloid peptide (Aβ), which is neurotoxic. The present study assessed the impact of BDNF on the toxic effects of Aβ25-35-induced apoptosis and the effects on BDNF-mediated signaling using the MTT assay, western blotting and reverse transcription quantitative polymerase chain reaction. Aβ25-35 was found to induce an apoptosis, dose-dependent effect on SH-SY5Y neuroblastoma cells, which peaked at a concentration of 20 μM after 24 h. A combination of Aβ25-35 and BDNF treatment increased the levels of Akt and decreased the level of glycogen synthase kinase-3β (GSK3β) in SH-SY5Y neuroblastoma cells. These findings indicated that BDNF administration exerted a neuroprotective effect against the toxicity of the Aβ25-35-induced apoptosis in these cells, which was accompanied by phosphoinositide 3-kinase/Akt activation and GSK3β phosphorylation. The mechanisms and signaling pathways underlying neuronal degeneration induced by the Aβ peptide remain to be further elucidated.