Ginsenoside Rb1 reduces neurodegeneration in the peri-infarct area of a thromboembolic stroke model in non-human primates

Ginsenoside Rb-1 (GRb(1)), a major component of the traditional herb ginseng, has been reported to show a neuroprotective effect in a rodent ischemic model. The purpose of this study was to investigate effects of GRb(1) on early and delayed brain injuries in a non-human primate thromboembolic stroke model. Thromboembolic stroke was induced by occlusion of the middle cerebral artery by injection of an autologous blood clot into the left internal carotid artery. GRb(1) (300 mu g/kg per day, i.v.) and vehicle were administered from 7 days before embolization to the day following embolization (total: 8 times). Neurological deficits were observed at 1, 6, and 24 h and at 2, 4, and 7 days after embolization. At 7 days after embolization, neuron damage in the peri-infarct area and core region were assessed by NeuN, TUNEL, and GFAP staining. GRb(1) improved the skeletal muscle coordination score of the neurologic deficits (median: GRb(1) vs vehicle = 10 vs 12, P<0.05). In the GRb(1) group, positive neurons expressed by NeuN staining were noted in the ischemic peri-infarct area, and TUNEL- and GFAP-positive cells significantly decreased, when compared with vehicle. These results demonstrated that GRb(1) ameliorated both early and delayed injuries in the thromboembolic stroke model in non-human primates.