Ameliorative effects of yokukansan on behavioral deficits in a gerbil model of global cerebral ischemia

The aim of this study was to investigate the neuroprotective effects of yokukansan, a traditional Kampo medicine, on the behavioral dysfunction induced by cerebral ischemia/reperfusion injury in gerbils. Gerbils were treated with yokukasan by oral gavage for 30 days, once per day, until the day before induction of ischemia, which was induced by occluding the bilateral common carotid artery for 5 min. The effects of yokukansan (50, 100 and 300 mg/kg) were examined by measuring neuronal damage and behavioral deficits (locomotor activity, 8-arm radial maze task). The anti-inflammatory and anti-oxidant properties of yokukansan were also examined. Administration of yokukansan at 300 mg/kg significantly reduced hippocampal neuronal death after brain ischemia, inhibited the ischemia-induced inflammatory response and DNA oxidative damage. Yokukansan also reduced ischemia-induced locomotor hyperactivity and improved memory impairment. These findings suggest that yokukansan can inhibit the inflammatory response, oxidative damage and subsequent neuronal death induced by cerebral ischemia/reperfusion injury, and also can contribute to improvement in neurological deficits following such injury.