Potential protection of curcumin against intracellular amyloid β-induced toxicity in cultured rat prefrontal cortical neurons

sRecently the neuronal toxicity of intracellular amyloid β (iAβ) in Alzheimer's disease is attracting more and more attention. The present study explored the effects of curcumin on the iAβ-induced toxicity in primary cultured rat prefrontal cortical neurons. The cell viability of primary cultured prefrontal cortical neurons decreased significantly after virus driven transfection of Aβ from 1 day to 7 days. Interestingly, administration of 1 μM, 10 μM or 20 μM of curcumin significantly inhibited the iAβ-induced toxicity in primary cultured rat prefrontal cortical neurons tested by MTT and LDH release assays. We further studied the involvements of apoptotic or neuroprotective pathway proteins in curcumin protection against iAβ-induced cytotoxicity in primary cultured rat prefrontal cortical neurons. The results demonstrated that the contents of activated caspase-3 increased significantly by iAβ, while curcumin significantly inhibited the iAβ-induced increases of activated caspase-3 tested by Western blot. And the contents of p-AKT decreased significantly after iAβ treatment, while administration of curcumin significantly inhibited the iAβ-induced decreases in the contents of p-AKT. The results suggest that curcumin may play a protective effect in primary cultured rat prefrontal cortical neurons against iAβ-induced cytotoxicity, and both AKT and caspase-3 are involved in the curcumin-induced protective effects.