Puerarin Protects Against β-Amyloid-Induced Microglia Apoptosis Via a PI3K-Dependent Signaling Pathway

Puerarin extracted from Radix puerariae is well-known for its anti-oxidative and neuroprotective activities. In this study, we investigated the protective effect of puerarin on amyloid-beta protein (A beta)-induced cytotoxicity and its potential mechanisms in BV-2 and primary microglial cells. We found that pretreatment with puerarin afforded protection against A beta-induced cytotoxicity through inhibiting apoptosis in BV-2 and primary microglial cells. This result was also confirmed by the activated caspase-3 assay. Phospho-Akt and Bcl-2 expression increased after pretreatment with puerarin in BV-2 and primary microglial cells exposed to A beta, whereas Bax expression and cytochrome c release decreased. In addition, puerarin treatment prevented the loss of mitochondrial membrane potential and reactive oxygen species production. Interestingly, these effects of puerarin against A beta insult were abolished by LY294002, an inhibitor of PI3K phosphorylation. Taken together, these findings suggest that puerarin prevents Ab-induced microglial apoptosis via the activation of PI3K/Akt signaling pathway, and might be a potential preventive or therapeutic agent for Alzheimer's disease.