Inhibitory effects of Eleutherococcus senticosus extracts on amyloid beta(25-35)-induced neuritic atrophy and synaptic loss.
Neurons with atrophic neurites may remain alive and therefore may have the potential to regenerate even when neuronal death has occurred in some parts of the brain. This study aimed to explore effects of drugs that can facilitate the regeneration of neurites and the reconstruction of synapses even in severely damaged neurons. We investigated the effects of Eleutherococcus senticosus extracts on the regeneration of neurites and the reconstruction of synapses in rat cultured cortical neurons damaged by amyloid beta (Abeta)(25-35). Treatment with Abeta(25-35) (10 microM) induced axonal and dendritic atrophies and synaptic loss in cortical neurons. Subsequent treatment with the methanol extract and the water extract of E. senticosus (10 - 1000 ng/ml) resulted in significant axonal and dendritic regenerations and reconstruction of neuronal synapses. Co-application of the extract and Abeta(25-35) attenuated Abeta(25-35)-induced neuronal death. We investigated neurite outgrowth activities of eleutherosides B and E and isoflaxidin, which are known as major compounds in E. senticosus. Although eleutheroside B protected against Abeta(25-35)-induced dendritic and axonal atrophies, the activities of eleutheroside E and isofraxidin were less than that of eleutheroside B. Although the contents of these three compounds in the water extract were less than in the methanol extract, restoring activities against neuronal damages were not different between the two extracts. In conclusion, extracts of E. senticosus protect against neuritic atrophy and cell death under Abeta treatment, and one of active constituents may be eleutheroside B.
Tohda
Chihiro
C
Division of Biofunctional Evaluation, Research Center for Ethnomedicine, Institute of Natural Medicine, University of Toyama, Toyama, Japan.
Ichimura
Mahoko
M
Bai
Yanjing
Y
Tanaka
Ken
K
Zhu
Shu
S
Komatsu
Katsuko
K
D016229:Amyloid beta-Peptides / Q000633:toxicity*; D000818:Animals; D001284:Atrophy / Q000139:chemically induced / Q000517:prevention & control*; D018929:Cell Culture Techniques; D045424:Complex Mixtures / Q000494:pharmacology* / Q000627:therapeutic use; D028001:Eleutherococcus / Q000737:chemistry*; D016501:Neurites / Q000187:drug effects* / Q000473:pathology; D009474:Neurons; D051381:Rats; D017207:Rats, Sprague-Dawley; D013569:Synapses / Q000187:drug effects* / Q000473:pathology
D016229:Amyloid beta-Peptides; D045424:Complex Mixtures