ABSTRACT
Objective Curculiginis extract has good scavenging effects on oxygen free radicals, and there is no curculiginis extract for AD research at home.The aim of this study was to explore the influence of Curculigoside on the cognitive learning and memory functions of senile dementia model rats induced by D-galactose combined with β-protein amyloid β25-35 (Aa25 35) and the expression level of hippocampus B-cell lymphoma-2 (Bcl-2), Bax, estrogen receptor (ER) protein and mRNA.Methods Forty SD rats weredivided into the control group (equal saline was intraperitoneal injected for six weeks consecutively, and equal saline was injected to the bilateral hippocampus in the seventh week), the model group (galactose was intraperitoneal injected for six weeks consecutively, and 4 mmol/L Aβ25-35 was injected to the bilateral hippocampus in the seventh week), the low dosage group and the high dosage group randomly (the stomach irrigation of low dosage 24mg/kg or the high dosage 72mg/kg curculigoside was applied every day, for 8 weeks), 10 rats in each group.After the treatment , the Morris water maze was conducted to test the space learning and memory functions of rats;the flow cytometry method was conducted to analyze the neuronal apoptosis conditions;the western blot was conducted to detect Bcl-2, Bax and ER protein level;the Realtime PCR was conducted to detect Bcl-2, Bax and ER mRNA level.Results Morris water maze test results: Compared with the model group, the escape latency (EL) of the rats of the model group, the low dosage group and the high dosage group on the 2nd, the 3rd, the 4th and the 5th day significantly extends (P<0.01), and the high dosage group significantly shortens (P<0.05) than the low dosage group.Space exploration test results: Compared with the proportion of the distance swum within the quadrant by the rats in the model group in the total distance [(30.14±5.10)%], that of the low dosage group, the high dosage group and the control group [(41.98±4.78)%, (46.17± 9.31)% and (50.13±6.81)%] significantly increases (P<0.01);in addition, the high dosage group is higher than the low dosage group (P<0.05).Compared with the apoptosis rate of rates in the model group[(7.11±1.78)%], that of the high dosage group, the low dosage group and the control group[(5.53±1.45)%], (4.11±1.03)% and (3.08±1.33)% significantly decreases (P<0.05).Compared with the control group, the Bcl-2 and Bax protein expression of the model group significantly increases, and the cell Bcl-1 and Bax of cells significantly decreases (P<0.05).Compared with the model group, the Bcl-2 and ER protein expression as well as the Bcl-2/Bax of the high dosage group and the low dosage group significantly increase, and the Bax protein expression significantly decreases (P<0.05).Compared with the mRNA expression (1.00 and 1.00) of Bcl-2 and ER in the control group, the mRNA expression (1.31 and 1.98) of the Bcl-2 and Bax in the model group significantly increases (P<0.05);compared with the mRNA expression (1.13 and 1.08) of Bcl-2 and ER in the model group, the Bcl-2 (1.95 and 2.01) and mRNA expression (1.81 and 1.96) of ER of the high dosage group and the low dosage group significantly increase (P<0.01).Conclusion Curculigoside plays an improving role in space learning and memory functions of senile dementia model rats, with the mechanism may be related to the protection to the hippocampus neurons by restraining Bax expression and neuronal apoptosis through the up-regulation of hippocampus ER and Bcl-2 expressions.