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.

Objective To investigate the effects of Dihuangyinzi(DHYZ) on behaviors and RAGE/p38 pathway in APP/PS1 mice.MethodTwenty APP/PS1 dementia mice were randomly divided into model group(n=10) and Chinese medicine group(n=10).The blank group was C57 BL/6 J normal mouse(n=10).The mice in Chinese medicine group were intragastric administration with DHYZ (9.75 g·kg-1·d-1).The mice in model group and blank group were treated with distilled water.After 30 days,the abilities of learning and memory of mice were detected by Morris water maze.The expression of amyloid-beta1-42(Aβ1-42) in the hippocampus and cortex was detected by immunohistochemistry.Reactive oxygen species of brain tissue were detected by DCFH-DA Methods in the brain of APP/PS1 mice.Gene expression level of receptor for advanced glycation end products(RAGE) was measured by real-time polymerase chain reaction (RT-PCR) in the cortex and hippocampus of APP/PS1 mice.The expression of phospho-mitogen-activated protein kinases (p38) was analyzed with Western blot and immunofluorescence analysis in the cortex and hippocampus of APP/PS1 mice.Results Behavioral Results showed that DHYZ significantly increased the distance((23.088±7.083)cm) and residence time((1.961±1.230)s)of effective area in Morris water maze on the fifth day(P<0.05,P<0.01)and remarkably increased the number of effective area crossings((1.607±0.405) times) and plats((0.893±0.283) times) in Morris water maze on the fifth day(P<0.01,P<0.05).DHYZ also significantly reduced the intracelluar ROS level(122.611±7.630) in the brain(P<0.01),and DHYZ could depress the expression of RAGE(1.467±0.081,7.983±0.136) and phosphorylation of p38 (0.376±0.026,0.538±0.016)in the cortex and hippocampus of APP/PS1 mice(P<0.01,P<0.05).Conclusions The Results demonstrate that DHYZ can partly improve memory impairment of APP/PS1 mice by the inhibition of RAGE/p38 pathway.