Methyl 3,4-dihydroxybenzoate protects primary cortical neurons against Aβ₂₅₋₃₅-induced neurotoxicity through mitochondria pathway

Abstract

Amyloid-β peptides (Aβ), which can aggregate into oligomers or fibrils in neurons, play a critical role in the pathogenesis of Alzheimer's disease (AD). Methyl 3,4-dihydroxybenzoate (MDHB), a phenolic acid compound, has been reported to have antioxidative and neurotrophic effects. The present study investigated the neuroprotective effects of MDHB against Aβ-induced apoptosis in rat primary cortical neutons. The primary cortical neurons were pretreated with different concentrations of MDHB for 24 hr, then incubated with 10 μM Aβ25-35 for 24 hr. The results showed that Aβ25-35 could induce neurotoxicity as evidenced by the decreased cell viability and the increased apoptotic rate. In parallel, Aβ25-35 significantly increased the reactive oxygen species accumulation and decreased mitochondrial membrane potential. However, pretreatment of the primary cortical neurons with MDHB could effectively suppress these cellular events caused by Aβ25-35 exposure. In addition, MDHB could increase the level of Bcl-2, decrease the level of Bax, and inhibit the activation of caspase-9 and caspase-3 in Aβ25-35 -treated primary cortical neurons. All these results were beneficial in their protective effect against Aβ-induced neurotoxicity. Our results suggest that MDHB has a neuroprotective effect that provides a pharmacological basis for its clinical use in the treatment of AD.

Keywords: Alzheimer's disease; amyloid-β peptides; apoptosis; neurons; neuroprotection.