ABSTRACT
Objective Rapamycin can improve characteristic pathology of AD by improving the level of autophagy.But, its internal mechanism still needs further study.This study was aimed to observe the protective effect of Rapamycin (RAPA) on the injury of rat pheochromocytoma (PC12) cells induced by β-amyloid protein25-35 (Aβ25-35).Methods PC12 cells in the logarithmic phase were randomly divided into 5 groups: control group(similar free-serum DMEM), model group, 10μmol/L RAPA treated group, 40μmol/L RAPA treated group and 160μmol/L RAPA treated group(add 10μmol/L, 40μmol/L RAPA, 160μmol/L respectively).Except the control group, each group was cultured with 20μmol/L Aβ25-35 to established the cell injury model.Results ①Compared with the survival rate of cells[(51.47±2.59)%] and the apoptosis rate of cells[(52.22±2.33)%] of the model group,the survival rate of cells in 10、40、160μmol/L RAPA treated groups and control group[(54.64±2.42)%, (64.79±2.91)% ,(56.50±2.55)% and (99.98±0.73)%] significantly increased, but the apoptosis rate of cells [(45.33±2.83)%, (36.89±2.85)%, (48.00±2.83)% and (3.33±2.45)%] significantly decreased(All P<0.05).②In model group,the expressions of p-PKB is 0.33±0.01, p-mTOR is 1.97±0.05, p-tau is 2.09±0.19.Compared with model group, in 10、40、160μmol/L RAPA treated groups and control group,these expressions of p-PKB (0.37±0.01, 0.42±0.01, 0.40±0.01 and 0.44±0.02) were significantly increased, however p-mTOR (1.64±0.05, 0.66±0.04, 0.35±0.01 and 0.62±0.01) and p-tau (2.02±0.15, 1.79±0.05, 1.86±0.06 and1.53±0.04) were decreased(All, P<0.05).ConclusionRAPA can increase Aβ25-35-induced PC12 cells viability, decrease cells apoptosis rates, and have a protective effect on Aβ25-35-induced PC12 cells death.The mechanism of its protective effect may be related to the inhibition of mTOR regulating PI3K/PKB/mTOR signal transduction pathway by negative feedback and the reduction of tau protein hyperphosphorylation.
ABSTRACT
Objective To determinted whether GM1 had a protective effect on injury induced by serum-deprivation and the possible mechanism in PC12 cells. Methods The viability of PC12 cells was quantified by MTT after serum-deprivation.The number of apoptotic cells and necrotic cells were determined by Hoechst 33258/PI staining.And the change of PKC protein expression on PC12 cells' membrane and cytosols was detected by Western blotting. Results 1.The viability of PC12 cells decreased after serum-deprivation and the serum-deprivation for 24 hours was chosen as an injury model in this research.Most of the PC12 cells presented apoptosis 24 hours after serum-deprivation.In addition,the PC12 cells' cytosols PKC protein decreased,while the PC12 cells' membrane PKC protein increased significantly,and this result suggested PKC's translocation to membrane and its activation.2.The viability of PC12 cells preincubated with GM1 in high concentrations(10,1,0.1?mol/L) increased significantly and GM1 protected PC12 cells from apoptosis after serum-deprived injury.GM1 reduced the damage of serum-deprivation on PC12 cells and inhibited PKC protein translocation after injury.3.The repair function of GM1 was effective to neuronal resume after serum-deprived injury.Conclusion Neuroprotective effects of GM1 on serum-deprived injury may be partly mediated through the regulation of PKC pathways and it is helpful for the recovery after injury.