Neuroprotective effects of a traditional herbal prescription on transient cerebral global ischemia in gerbils

Abstract

Aim of the studyKyung-Ok-Ko (KOK), a traditional herbal prescription composed of Rehmannia glutinosa var. purpurae, Panax ginseng, Poria cocos, Lycium chinense, Aquillaria agallocha and honey, has been used to treat age-related symptoms, such as amnesia or dementia, and has been shown to ameliorate scopolamine-induced memory impairment in mice. However, the effects of KOK on transient cerebral global ischemia-induced brain damage are unclear. Materials and methodsTransient cerebral global ischemia was induced by occluding the bilateral common carotid artery for 5min followed by reperfusion for 7days. KOK (0.25, 0.5, 1, or 2g/kg) was administered orally immediately after reperfusion and once a day over the next 7days. Y-maze or novel object recognition tasks were to analyze learning and memory capabilities at 4 or 5days after reperfusion, respectively. Histochemistry and immunohistochemistry were used for evaluation of the effect of KOK on neuronal degeneration. ResultsHistochemical studies showed that KOK increased the number of viable cells detected by Nissl staining and decreased the number of degenerated neuronal cells detected by Fluoro-Jade B staining in the hippocampal CA1 region. In the immunohistochemical study, the sub-chronic KOK administration attenuated the ischemia-induced activation of microglia and astrocytes and the increase of cytokine IL-1β (P<0.05). In addition, KOK administration significantly attenuated the ischemia-induced cognitive impairments observed in the Y-maze and novel object recognition tasks (P<0.05). ConclusionThese findings suggest that the neuroprotective effects of KOK may be mediated by its anti-inflammatory activities, resulting in the attenuation of memory impairment.