The Neuroprotective Effect of White Ginseng (Panax ginseng C. A. Meyer) on the Trimethyltin (TMT)-Induced Memory Deficit Rats

The present study examined the effects of Korean white ginseng (WG, Panax ginseng C. A. Meyer) on the learning and memory function and the neural activity in rats with trimethyltin (TMT)-induced memory deficits. The rats were administered with saline or WG (WG 100 or 300 mg/kg, p.o.) daily for 21 days. The cognitive improving efficacy of WG on the amnesic rats, which was induced by TMT, was investigated by assessing the Morris water maze test and by performing immunohistochemistries on choline acetyltransferase (ChAT), acetylcholinesterase (AchE), cAMP responsive element binding protein (CREB) and brain derived neurotrophic factor (BDNF). The rats treated with TMT injection (control group) showed impaired learning and memory of the tasks, but the rats treated with TMT injection and WG administration produced significant improvement of the escape latency to find the platform in the Morris water maze at the 2nd and 4th days compared to that of the control group. In the retention test, the WG 100 and WG 300 groups showed significantly increased crossing number around the platform compared to that of the control group (p < 0.001). Consistently with the behavioral data, result of immunohistochemistry analysis showed that WG 100 mg/kg significantly alleviated the loss of BDNF-ir neurons in the hippocampus compared to that of the control group (p < 0.01). Also, treatment with WG has a trend to be increased the cholinergic neurons in the hippocampal CA1 and CA3 areas as compared to that of the control group. These results suggest that WG may be useful for improving the cognitive function via regulation of neurotrophic activity.