Effects Of Ginsenoside Rg1on Learning And Memory Of Infant Sd Rats Exposed By Lead And Bdnf Expression In Its Hippocampus

Objective: Lead poisoning infant animal models were established, and the protectioneffects of ginsenoside Rg1on learning and memory dysfunction in the lead-exposedinfant rats were observed. The relationship between treatment effects and BDNFexpression level was analyzed. A possible mechanism of ginsenoside Rg1effecting onlead-exposed infant rats in learning and memory function was investigated.Methods: The health male21-days old SD rats were chosen to establish leadpoisoning animal models. Lead poisoning animal models were established byperitoneal injecting30mg/kg lead acetate. Control group, lead poisoning group,ginsenoside Rg1(set5mg/kg,15mg/kg,45mg/kg three doses) intervention group,lead poisoning routine treatment drug DMSA group were designed. Whole blood leadlevels were determined by graphite furnace atomic absorption spectrometry; thelearning and memory function of animals were analysed by Morris water maze; thehistopathological change of hippocampus tissue were observed by HE staining; thelevels of BDNF protein in hippocampus tissue were analysed by western blot. Thestatistical analysis and statistical figure were dealt with SPSS17.0and SigmaPlot10.0.Results:1. The effects of ginsenoside Rg1and DMSA on blood lead level of lead exposedinfant rats: Compared with the control group, blood lead level in lead exposed groupswere increased significantly (P<0.05); compared with the model group, blood leadlevels in the intervention groups were reduced significantly (P<0.05).2. The effects of ginsenoside Rg1and DMSA on the hippocampus pathomorphology change indued by lead: The hippocampus tissues were symmetrical; thephotomicrographs showed that the structures of hippocampus cells in control groupwere tight, the intercellular space was normal, cells protuberant were clearly visible.However, in the model group, the number of cells in the hippocampus was decreased,arranging disorderly, intercellular space became widen, the cell nuvleus becamepyknosis. The hippocampus tissue impairment of lead poisoning infant rats wasimproved differently in three doses ginsenoside Rg1and DMSA group.3. The effects of ginsenoside Rg1and DMSA on Morris water maze test of leadexposed infant rats: Orientation navigation experiments showed that with theincreasing of days training, the escape latency period and total distance were shorted.On the fourth day training, compared with the control, model group the escape latencyperiod increased significantly (P<0.05); compared with model group, the escapelatency period in each ginsenoside Rg1dose groups and DMSA group weresignificantly reduced (P<0.05). On the fifth day training, compared with the controland model group, the escape latency period and total distance were significantlyincreased (P<0.05, P<0.01); compared with the model group, the escape latencyperiod and total distance of high dose ginsenoside Rg1group were significantlyshortened (P<0.05, P<0.01). On the sixth day training, compared with the controlgroup, the escape latency period and total distance of the model group weresignificantly increased (P<0.01); compared with the model group, the escape latencyperiod of each group were significantly reduced(P<0.01), the total distance of highdose ginsenoside Rg1group and DMSA group were significantly shortened (P<0.01).Searching space experiments showed that, compared with the control group, thenumber of through the platform in model group was diminished (P<0.01), thepercentage of target quadrant stay time was significantly reduced (P<0.01); comparedwith the model group, the number and the percentage of target quadrant stay time ofeach dose ginsenoside Rg1groups and DMSA group were significantly increased(P<0.01).4. The effects of ginsenoside Rg1and DMSA on the BDNF protein expression level in the hippocampuses of lead exposed infant rats: Compared with the control group,the BDNF protein expression level got descent in the model group hippocampus(P<0.01); compared with the model group, BDNF protein expression level ofhippocampus in the medium, high dose ginsenoside Rg1groups and DMSA groupwas increased, especially in45mg/kg dose ginsenoside Rg1group.Conclusions:1. Lead poisoning inducing learning and memory dysfunction in infant rats had somerelationship with the level of BDNF protein expression in hippocampus.2. The ginsenoside Rg1could improve the neural learning and memory dysfunctioninduced by lead poisoning in infant rats, including reducing the level of blood Pb andenhancing the capability of orientation navigation and searching space, especially in45mg/kg dose ginsenoside Rg1group, suggesting that the nerve protection effectshad some relationship with the BDNF protein expression in hippocampus.