Abstract: ObjectiveTo evaluate the possible effect of SSY-B2 on reducing the loss of neurons and enhancing the expression of nerve growth factor(NGF).MethodsMale adult SD rats were divided randomly into 6 groups as sham group,model group,positive control agent piracetam group, SSY-B2 low(1.5g crude drug/kg), medium(3g crude drug/kg)and high dosage (6g crude drug/kg)group.Bilateral fornix/fimbria transection was carried out in the rats' septohippocampal pathway and 6 weeks' drug treatment was administered with different doses of SSY-B2 and positive control agent piracetam. After behavioral tests, the numbers of neurons in medial septum and immunoreactive products of NGF in different areas were measured, using Nissle staining and immunohistochemical methods.ResultsThere was neural loss in medial septum after fornix /fimbria transection, but SSY-B2 at each dosage markedly reduced the loss(59.13±22.02,50.60±23.18,63.93±18.35,the number of neurons for three SSY-B2 dosage groups,P<0.005 for all compared with the model group 20.33±14.01).The number of NGF positive cells decreased in model group, but did not show significant statistic difference compared with the sham group (P>0.05) in the medial septum, polymorph layer of dentate gyrus and entorhinal cortex/Subiculum area. In the medial septum, all three dosage enhanced the expression of NGF positive cells(145.1±57.7,161.3±08.2,200.6±58.2,the number of neurons for three SSY-B2 dosage group,P<0.005 for all compared with the model group 50.2±48.6). SSY-B2 at low and medium dosage group also increased the number in both entorhinal cortex/Subiculum and polymorph layer of dentate gyrus.Conclusions SSY-B2 can reduce the loss of neurons in the medial septum, which may be involve in increasing expression of NGF;NGF expression in dentate gyrus, subiculum of hippocampal formation and entorhinal cortex increased by SSY-B2 may play a role in the compensation of these area for learning/memory.

Key words: Traditional Chinese Medicine, SSY-B2, neurons, nerve growth factor(NGF)