Anti-apoptotic effect of memantine in a rat hippocampal cell model of Alzheimer's disease: morphology and cellular mechanism

Abstract Objective: Memantine as a blocker of NMDA channels is administrated to patients with Alzheimer’s disease (AD). Amyloid beta protein (Aβ) play important role in the progression of Alzheimer's disease. There is evidence that memantine is able to affect the amyloid precursor protein (APP), amyloid beta protein metabolism. The presence study has been designed to assess the anti-apoptotic mechanisms of memantine on Aβ1–42 -induced neurotoxicity.Methods: Cultures of hippocampal neurons were divided into eight groups consisting of an untreated control, cells treated with amyloid-β1-42 (2 μM); memantine (5 μM), NMDA (3 μM), memantine before and after amyloid-β1-42, memantine before and after NMDA for 48 h. Changes in neuronal morphology and anti-apoptotic responses for each experimental group were assessed via MTT, lactate dehydrogenase (LDH) release, immunostaining, propidium iodide (PI) staining and western blot.Results: We observed that the Aβ1-42-induced neurotoxicity was inhibited through the addition of memantine at concentrations of 1-5 μM. Aβ1-42 and NMDA induced changes in neuronal morphology and reduction in cell number and neurite length in cultured rat hippocampal neurons after 48 h of treatment compared with control group. Moreover, apoptosis properties, including DNA fragmentation and a low ratio of Bcl-2/Bax were observed in hippocampal neurons following treatment of Aβ1-42 and NMDA. Further observation demonstrated that the mitochondrial pathway through release of cytochorome c and caspase-3 activity was involved in the apoptosis induction. Whereas, results indicated that memantine is able to reverse Aβ1-42 induced neurotoxicity.Conclusions: The findings of presence study suggest that memantine has a neuroprotective potential via NMDA channel blockade and could be introduced as a promising therapeutic agent to decrease the risk of developing AD.