Effect of early intervention of electroacupuncture on learning-memory ability and level of hippocampal phosphorylated Tau protein in SAMP8 mice

Abstract

To explore the effect of early intervention electroacupuncture (EA) at "Baihui" (GV 20), "Dazhui" (GV 14) and "Shenshu" (BL 23) on the learning-memory ability and the expression of phosphorylated Tau protein in the hippocampus of SAMP8 mice, so as to provide reference for the intervening period of EA for Alzheimer's disease (AD). A total of 36 3-month old SAMP8 mice were randomly divided into a model group, a 3-month-old EA group and a 9-month-old EA group, 12 mice in each group. Twelve normal SAMR1 mice with the same age were taken as the control group. The mice in the 3-month-old EA group and 9-month-old EA group were treated with EA at "Baihui" (GV 20), "Dazhui" (GV 14) and "Shenshu" (BL 23) separately 3 months old and 9 months old (continuous wave, 2 Hz, 1.5-2 mA), 20 min each time, once a day, 8 days as a course of treatment, with an interval of 2 days between courses, totally 3 courses of treatment were given. The mice sample in each group was collected at the age of 10 months after the learning-memory ability tested by Morris water maze. The expression of phosphorylated Tau protein in the hippocampus was detected by immunohistochemistry and Western blot, and the expression of Tau mRNA was detected by real-time PCR. Compared with the control group, in the model group, the escape latency was significantly increased (P<0.01), the time of stay in the original platform quadrant and the number of crossing the platform quadrant were reduced (P<0.01), and the expressions of phosphorylated Tau protein and Tau mRNA in hippocampus were increased (P<0.01). Compared with the model group, in the 3-month-old EA group and 9-month-old EA group, the escape latency was significantly reduced (P<0.05), the time of stay in the original platform quadrant and the number of crossing the platform quadrant were increased (P<0.05), and the expressions of phosphorylated Tau protein and Tau mRNA in hippocampus were reduced (P<0.05). Compared with the 9-month-old EA group, in the 3-month-old EA group, the escape latency was significantly reduced (P<0.05), the time of stay in the original platform quadrant and the number of crossing the platform quadrant were increased (P<0.05), and the expressions of phosphorylated Tau protein and Tau mRNA were reduced (P<0.01). The early EA intervention could more effectively improve the learning-memory ability and inhibit phosphorylation of Tau protein in the hippocampus of SAMP8 mice.