The Mechanism Of B-Amyloid-Induced By Glutamic Acid To PC12 Cell Lines And The Intervention Of Ginsenoside Rg₂

Objective To study the excitotoxicity-impaired model of of PC12 cell lines induced by glutamic acid (Glu) and observe the change of cellular viability , intracellular [Ca²⁺]i concentration, the contents of MDA, NO in the supernatant ,the expression of Calpain II,Caspase-3 and Ap after impairment induced by Glu, and the intervention of ginsenoside Rg₂ on the excitototoxicity damage of PC12 cell line was explored as well.Methods Excitotoxicity damage was induced by PC 12 cells culture with lmmol/L Glu and serum-free medium for 24 hour . Adding different dosage of ginsenoside Rg₂ to medium meanwhile injuring PC12 cells, and contrasted with nimodipine .The MTT reduction ability and the contents of MDA, NO in the supernatant were measured by biochemical method; Fura-2/AM was utilized as fluorescence probe to detect intracellular [Ca²⁺] i concentration , the immunocytochemical technique was used to check the expression of Calpain, Caspase-3 and Aβ in PC 12 cells.Results The metabolic rate of MTT of C12 cells in the model group was decreased, the contents of DA, NO in the supernatant and intracellular [Ca²⁺]i were increased i and the expression of Calpain â…¡, Caspase-3, Aβ in PC12 cells were also increased comparing with the control group ,the difference had statistical significance(P<0.05). The metabolic rate of MTT of PC 12 cells treated by ginsenoside Rg₂ was increased, the contents of MDA, NO in the supernatant , the [Ca²⁺]i level in the intracellular , and the expression of Calpain â…¡, caspase-3, and Aβ in PC12 cells were decreased as compared with the model group , the difference had statistical significance (P<0.05). Besides, the protective effect of high dosage ginsenoside Rg₂ (0.2mmol/L) was superior than that of low and median dosage ginsenoside Rg₂ treated group, and the effects had dosage dependence .Conclusion The MTT metabolic rate was decreased and the [Ca²⁺]i overloading was induced, the expression of Calpain II was activated , the excessive production of the free radicals were caused , the expression of Caspase-3 induced the abnormal splitting of APP were enhanced after PC 12 cells were injuried by glu, and therefore the formation of Aβ was increased . The glu-induced injury to PC 12 cells could be attenuated by improving the cell metabolic rate ,inhibiting Ca²⁺ influx, decreasing the...