Study of the protective effects of nootropic agents against neuronal damage induced by amyloid-beta (fragment 25–35) in cultured hippocampal neurons

Abstract Background Alzheimer's disease (AD) is a common neurodegenerative disorder, in which progressive neuron loss, mainly in the hippocampus, is observed. The critical events in the pathogenesis of AD are associated with accumulation of β-amyloid (Aβ) peptides in the brain. Deposits of Aβ initiate a neurotoxic “cascade” leading to apoptotic death of neurons. Aim of this study was to assess a putative neuroprotective effects of two nootropic drugs: piracetam (PIR) and levetiracetam (LEV) on Aβ-injured hippocampal neurons in culture. Methods Primary cultures of rat's hippocampal neurons at 7 day in vitro were exposed to Aβ(25–35) in the presence or absence of nootropics in varied concentrations. Flow cytometry with Annexin V/PI staining was used for counting and establishing neurons as viable, necrotic or apoptotic. Additionally, release of lactate dehydrogenase (LDH) to the culture medium, as a marker of cell death, was evaluated. Results Aβ(25–35) caused concentration-dependent death of about one third number of hippocampal neurons, mainly through an apoptotic pathway. In drugs-containing cultures, number of neurons injured with 20 μM Aβ(25–35) was about one-third lesser for PIR and almost two-fold lesser for LEV. When 40 μM Aβ(25–35) was used, only LEV exerted beneficial neuroprotective action, while PIR was ineffective. Conclusions Our results suggest the protective potential of both studied nootropics against Aβ-induced death of cultured hippocampal neurons with more powerful neuroprotective effects of LEV.