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

OBJECTIVE

Kyung-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.

METHODS

Transient cerebral global ischemia was induced by occluding the bilateral common carotid artery for 5 min followed by reperfusion for 7 days. KOK (0.25, 0.5, 1, or 2 g/kg) was administered orally immediately after reperfusion and once a day over the next 7 days. Y-maze or novel object recognition tasks were to analyze learning and memory capabilities at 4 or 5 days after reperfusion, respectively. Histochemistry and immunohistochemistry were used for evaluation of the effect of KOK on neuronal degeneration.

RESULTS

Histochemical 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).

CONCLUSIONS

These findings suggest that the neuroprotective effects of KOK may be mediated by its anti-inflammatory activities, resulting in the attenuation of memory impairment.