Abstract:

To investigate the effect of ginseng protein (GP) on neurons damaged  by beta amyloid protein1-40 (Aβ1-40) and hydrogenperoxi
de (H2O2),and to clarify the neuroprotective effect of GP and its mechanism. Methods The primary neurons were isolated and purified from cerebral cortex of suckling mouse and  cultured for 12 d,and damaged by 30  μmol•L-1Aβ1-40 and 200 μmol•L-1 H2O2. Then the damaged cells  were randomly divided into model group (Aβ1-40 model group and H2O2 model group,no drugs),GP group and  GP medicated  serum  group. MTT method was used to detect the  survival rates of cells;Qiagen was used to detect the  activities of NOS and levels of NO  in culture supernatant,and  Hoechst 33342/PI fluorescent staining method was used to detect the apoptotic  and necrotic rates of cells. Results It was observed that by the treatment of Aβ1-40  and H2O2,the  number of neuron was decreased,the axons shortened or disappeared,the karyopyknosis concentrated into a bright blue（dyed by Hoechst 33342）,and some cells were dyed into red by PI under inverted flurescence microscope; after adding GP and its medicated serum,the  number of cells was obviously increased,the cells stretched,the  nuclei　were round and light blue,and the number of cells dyed by PI into red was reduced. The MTT results showed that the  survial rate of cells in   GP group was obviously higher than that in model group (P<0.05 or P<0.01).There was no significant difference in  the  survival rate of cells between  GP medicated serum group and  model group (except 5% GP medicated serum group,P>0.05). The activity of NOS and level of NO in culture supernatant in  GP group were significantly lower than those in model group (P<0.05 or P<0.01). The apoptotic rates of cells in GP group and GP medicated serum group were obviously lower than that in model group detected by Hoechst 33342/PI method(P<0.05 or P<0.01). There was no significant differences of  the necrotic rates of neurons between GP group, GP medicated group and model group(P>0.05).Conclusion GP protein has the neuroprotective effect,and its mechanism is related to the reduction of the activity of NOS and the level of NO and the inhibition of apoptosis of neurons.

Key words: ginseng protein;serum;neuron;amyloid-&beta, protein;apoptosis