Achyranthes bidentata Blume extract protects cultured hippocampal neurons against glutamate-induced neurotoxicity

We have prepared an aqueous extract of Achyranthes bidentata Blume, a Chinese medicinal herb commonly prescribed for arthritis treatment or immnopotentiation, and have found that Achyranthes bidentata extract promotes nerve growth and prevents neuronal apoptosis.Aim of the studyTo investigate the protective effect of Achyranthes bidentata extract against glutamate-induced neurotoxicity in primary culture of rat hippocampal neurons.Materials and methodsWe accomplished MTT assay for cell viability, Hoechst 33342 staining, and flow cytometry for cell apoptosis analysis to examine the effects of Achyranthes bidentata extract on glutamate-induced neurotoxicity, and also used Fluo 4-AM measurement, RT-PCR and Western blot analysis to determine the changes in intracellular calcium concentration [Ca2+]I, and mRNA and protein levels of Bcl-2, respectively, concurrently accompanied with the influences of Achyranthes bidentata extract.ResultsAchyranthes bidentata extract was found to inhibit glutamate-induced neuronal damage in a dose- and time-dependent manner. On the other hand, Achyranthes bidentata extract depressed glutamate-induced elevation of intracellular calcium concentration [Ca2+]i, and also antagonized glutamate-evoked decreases in Bcl-2 expression at mRNA and protein levels.ConclusionThe results suggest that Achyranthes bidentata extract prevents glutamate-induced cell damage in primarily cultured hippocampal neurons by inhibiting an increase in [Ca2+]i, and reversing the down-regulation of Bcl-2.