Neuroprotective effects of Eleutherococcus senticosus bark on transient global cerebral ischemia in rats

Ethnopharmacological relevance: Eleutherococcus senticosus Maxim., classified into the family of Araliaceae, is used in a variety of diseases in traditional Korean medicine including ischemic heart disease. Aim of the study: To determine the neuroprotective effects of Eleutherococcus senticosus on global cerebral ischemia. Materials and methods: A four-vessel occlusion (4-VO) rat model was used to evaluate the potential protective effects against transient global cerebral ischemia ethanol extracts of Eleutherococcus senticosus was orally administered at doses of 3, 30, and 300 mg/kg twice at times of 0 and 90 min after reper-fusion. The effects on memory deficit were investigated by using a Y-maze neurobehavioral test after brain ischemia, and the effects on hippocampal neuronal damage were measured 7 days after ischemia. The expressions of glial fibrillary acid protein (GFAP). CD11b antibody (OX-42), and cyclooxygenase-2 (COX-2) were investigated by immunohistochemistry. Results: Oral administration of Eleutherococcus seticosus at 30, 100 and 300 mg/kg significantly reduced hippocampal CA1 neuronal death by 3.5%, 25.9% and 53.1%, respectively, compared with a vehicle-treated group. Oral administration of Eleutherococcus senticosus at 300 mg/kg inhibited 81.9% of the decrease in spontaneous alternation induced by 4-VOin the Y-maze test, and also attenuated ischemia-induced activation of COX-2, GFAP and OX-42 in the hippocampal CM region. Conclusion: Eleutherococcus senticosus protects delayed neuronal death in the CA1 region of the hippocampus against global cerebral ischemia in rats with the recovery of spatial memory, which can be considered as the normal functioning of the hippocampus. Regarding the immunohistochemical study, the effect of Eleutherococcus senticosus may be attributable to its anti-inflammatory properties through the inhibition of COX-2 expression, microglia and astrocyte expression. (C) 2011 Elsevier Ireland Ltd. All rights reserved.