Protective Effect Of Tea Polyphenols Against MPP~+-induced Injury In PC12 Cells

PartⅠProtective effect of TP against MPP+-induced injury in PC12 cellsObjective To investigate effect of TP on MPP+-induced cell viability loss in cultured PC12 cells.Methods Cell viability was measured by methylthiazolyltetrazolium(MTT) assay after PC12 cells were treated with various concentrations of TP(50,100,200,400mg/L) and/or MPP+(100,250,500μmol/L) for 24 hours in vitro.Results Compared with control group, the survival rate of PC12 cells were significantly decreased in 250 and 500μmol/L MPP+-treated group. The neurotoxic effect of MPP+ were significantly attenuated by TP,when the cells were co-incubated with MPP+ and different concentrations of TP for 24h,and maximal rescue occurred at a concentration of 200 mg/L.Conclusion TP exhibited neuroprotective effect on the MPP+-induced cytotoxicity in a dose-dependent manner in the PC12 cells.PartⅡEffect of TP on oxidative stress and apoptosis in MPP+-induced PC12 cellsObjective To explore the effect of TP on oxidative stress and apoptosis in MPP+-induced PC12 cells.Methods The level of intracellular ROS and apoptosis ratio were detected by flow cytometry FACS after the PC12 cells were treated with TP(200mg/L) and/or MPP+(250μmol/L) for 24 hours in vitro.Results Compared with control group, the level of intracellular ROS and apoptosis ratio in MPP+-treated group were significantly higher when there was no significant difference in the group of MPP+ co-incubuted with TP.Conclusion TP inhibited the increase of ROS and apoptosis ratio induced by MPP+ in PC12 cells.PartⅢEffect of TP on mRNA expression level of Bcl-2 in MPP+-induced PC12 cellsObjective To explore the effect of TP on mRNA expression level of Bcl-2 in MPP+-induced PC12 cells.Methods The mRNA expression level of Bcl-2 were detected by reversed transcriptive polymerase chain reaction (RT-PCR) after the PC12 cells were incubated with TP(200mg/L) and/or MPP+(250μmol/L) for 24 hours in vitro.Results Compared with control group, the level of Bcl-2 mRNA expression in MPP+-treated group were significantly decreasead when there was no significant difference in the group of MPP+ co-incubuted with TP .TP-treated group were remarkably elevated.Conclusion TP upregulated the expression of Bcl-2 in MPP+-induced PC12 cells.