Study on Improvement Effects of Total Ginsenosides on D-galactose Induced PC 12 Cell Senescence and Its Me- chanism / 中国药房

ABSTRACT

OBJECTIVE：To study the improvement effects of total ginsenosides on the senescence of PC 12 cells induced by D-galactose and its mechanism. METHODS ：Rat pheochromocytoma （PC12）cells were treated with D-galactose to establish cell senescence model. CCK- 8 method was used to screen the D-galactose modeling concentration and total ginsenosides concentration. Normal control group ，model group ，total ginsenosides low and high concentration groups were set up. Cell senescence ，cell apoptosis rate ，apoptotic cycle and mitochondrial membrane potential （MMP），cell adenosine triphosphate （ATP）and reactive oxygen species （ROS）levels in each group were detected. The expression of apoptosis related proteins [B lymphoma 2（Bcl-2）and its related egg X protein （Bax），cytochrome C （Cyt-C）] and oxidative damage related proteins [nuclear factor 2 related factor 2 （Nrf2），heme oxygenase 1（HO-1）] were detected. In addition ，positive drug group [ 5 mmol/L N-acetyl-L-cysteine（NAC）] and positive control group [ D-galactose+5 mmol/L NAC] were set up to compare the levels of oxidative damage related proteins. RESULTS：D-galactose could significantly inhibit the survival rate of PC 12 cells，with a critical concentration of 20 mg/mL. The total ginsenosides could significantly increase the survival rate of D-galactose induced senescent cells with a median effective concentration（EC50）of 65 μg/mL，and then the low and high concentrations of total ginsenosides were set at 55 and 65 μg/mL. Compared with normal control group ，the number of aging cells increased ，the apoptotic rate and percentage of G 1 phase were significantly increased i n model group. the percentage of S phase ，MMP and ATP contents ，the protein expression of Bcl- 2 and Cyt-C in mitochondria were decreased significantly ，whileROS content ，the protein expression of Bax ，Nrf2 and Cyt-C protein in endochylema were increased significantly （P＜0.05 or P＜0.01）. Compared with model group ，the number of E-mail：sunqiao150509@163.com aging cells reduced ，the apoptosis rates and percentage of G 1 phase were significantly decreased in total ginsenosides low and high concentration groups ，the percentage of S phase ，the contents of MMP and ATP （except for low concentration group ），protein expression of Bcl- 2，Nrf2 and HO- 1 as well as protein expression of Cyt-C in mitochondria were increased significantly ；ROS level （except for low concentration group ）and Bax protein as well as protein expression of Cyt-C were decreased significantly. The protein expression of Nrf 2 and HO- 1 were increased significantly in positive control group （P＜0.05 or P＜0.01）， but it was lower than that of total ginsenosides groups . CONCLUSIONS：Total ginsenosides can improve D-galactose induced senescence of P 12 cells，the mechanism of which may be related to activating Nrf 2 antioxidant signal pathway to antagonize D-galactose induced oxidative stress and alleviating mitochondrial dysfunction.