Sodium ferulate prevents amyloid-beta-induced neurotoxicity through suppression of p38 MAPK and upregulation of ERK-1/2 and Akt/protein kinase B in rat hippocampus.

Aim: To observe whether an amyloid beta (Abeta)-induced increase in interleukin (IL)-1beta was accompanied by an increase in the p38 mitogen-activated protein kinase (MAPK) pathway and a decrease in the cell survival pathway, and whether sodium ferulate (SF) treatment was effective in preventing these Abeta-induced changes.

Methods: Rats were injected intracerebroventricularly with Abeta25-35. Seven days after injection, immunohistochemical techniques for glial fibrillary acidic protein (GFAP) were used to determine the astrocyte infiltration and activation in hippocampal CA1 areas. The expression of IL-1beta, extracellular signal-regulated kinase (ERK), p38 MAPK, Akt/protein kinase B (PKB), Fas ligand and caspase-3 were determined by Western blotting. The caspase-3 activity was measured by cleavage of the caspase-3 substrate (Ac-DEVD-pNA). Reverse transcription-polymerase chain reaction was used to analyze the changes in IL-1beta mRNA levels.

Results: Intracerebroventricular injection of Abeta25-35 elicited astrocyte activation and infiltration and caused a strong inflammatory reaction characterized by increased IL-1beta production and elevated levels of IL-1beta mRNA. Increased IL-1beta synthesis was accompanied by increased activation of p38 MAPK and downregulation of phospho-ERK and phospho-Akt/PKB in hippocampal CA regions prepared from Abeta-treated rats, leading to cell death as assessed by activation of caspase-3. SF significantly prevented Abeta-induced increases in IL-1beta and p38 MAPK activation and also Abeta-induced changes in phospho-ERK and phospho-Akt/PKB expression levels.

Conclusion: SF prevents Abeta-induced neurotoxicity through suppression of p38 MAPK activation and upregulation of phospho-ERK and phospho-Akt/PKB expression.