Protection of Flupirtine on β-Amyloid-Induced Apoptosis in Neuronal Cells In Vitro: Prevention of Amyloid-Induced Glutathione Depletion

Abstract: Effective drugs are not available to protect against β-amyloid peptide (Aβ)-induced neurotoxicity. Cortical neurons from rat embryos were treated with the toxic fragment Aβ25-35 at 1 µ M in the presence or absence of flupirtine, a triaminopyridine, successfully applied clinically as a nonopiate analgesic drug. Five days later 1 µ M Aβ25-35 caused reduction of cell viability to 31.1%. Preincubation of cells with flupirtine (1 or 5 µg/ml) resulted in a significant increase of the percentage of viable cells (74.6 and 65.4%, respectively). During incubation with Aβ25-35 the neurons undergo apoptosis as determined by appearance of the characteristic stepladder-like DNA fragmentation pattern and by the TUNEL technique. Aβ25-35-induced DNA fragmentation could be abolished by preincubation of the cells with 1 µg/ml flupirtine. Incubation with Aβ25-35 reduces the intraneuronal level of GSH from 21.4 to 7.4 nmol/10⁶ cells. This depletion could be partially prevented by preincubation of the cells with flupirtine. Thus, flupirtine may be adequate for the treatment of the neuronal loss in Alzheimer's disease (where Aβ accumulates in senile plaques) and probably other neurological diseases such as amyotrophic lateral sclerosis.