RESUMEN
Objective To investigate the effects of Dihuang Yinzi (DY) on the receptor for advanced glycation end-products(RAGE)/reactive oxygen species(ROS)/apoptosis pathway in SH-SY5Y cells induced by amyloid-beta1-42 (Aβ1-42) oligomer. Methods Firstly, we adopted methyl thiazolyl tetrazolium(MTT) method to detect the cell vitality in fetal bovine serum (FBS) group, blank serum group, and low-, middle- and high- dose DY-containing serum groups, so as to confirm the optimal concentration and treatment time of DY-containing serum. Secondly, we applied MTT method to detect cell vitality and applied Annexin V/propidium iodide (PI) staining method to observe the apoptosis of SH-SY5Y cells treated with 0~20 μmol/L Aβ1-42 for 24 and 48 h, so as toconfirm the optimal concentration and treatment time of Aβ1-42 for establishing Alzheimer's disease (AD) model in vitro. Thirdly, MTT method was used for the detection of cell vitality, and Annexin V/PI staining method was used for detection of the apoptosis of SH-SY5Y cells in blank serum group, model group, western medicine control group and low-, middle-and high-dose DY-containing serum groups, and Dihydroethidium (DHE) method was used for the assay of ROS contents, so as to observe the effect of DY on the recovery of injured SH-SY5Y cells induced by Aβ1-42. Finally, we applied Western blot method to detect the expression level of RAGE in SH-SY5Y cells of blank group, model group and DY-containing serum group; after Aβ1-42-induced SH-SY5Y cells were transfected with RAGE gene, we adopted DHE staining method and Annexin V/PI staining method to detect ROS content and cell apoptotic rate in all of the above groups, so as to observe the effect of DY on SH-SY5Y cell apoptosis and RAGE expression. Results The cell vitalities were increased in low- and middle-dose DY-containing serum groups at 24 h (P < 0.05 or P < 0.01 compared with that in the blank serum group). The conditions for the establishment of AD model in vitro were as follows: the optimal concentration of Aβ1-42 was 5μmol/L, and the treatment time was 24 h. The cell vitalities were significantly enhanced, the cell apoptotic rate and ROS content were significantly lowered in Aβ1-42-induced SH-SY5Y cells of the medication groups(P <0.05 or P < 0.01 compared with those in the model group) , and the cell vitality was the highest and the cell apoptotic rate was the lowest in the middle-dose DY-containing serum group. The RAGE expression level was decreased in Aβ1-42-induced SH-SY5Y cells of the middle-dose DY-containing serum group(P < 0.05 compared with that in the model group) . ROS content and cell apoptotic rate were decreased in Aβ1-42-induced SH-SY5Y cells transfected with RAGE gene in the middle-dose DY-containing serum group (P<0.01). Conclusion DY may play an anti-oxidative role through inhibiting the production of ROS and cell apoptosis, thus to suppress RAGE protein and to achieve the preventive and therapeutic effect for AD.