[Effect of electroacupuncture on the P35/P25-cyclin-dependent kinase 5-Tau pathway in hippocampus of rats with Alzheimer's disease].

Objective: To investigate the effect of electroacupuncture on the P35/P25-cyclin-dependent kinase 5 (CDK5)-Tau pathway in rats with Alzheimer's disease (AD), as well as the mechanism of electroacupuncture in the prevention and treatment of AD.

Methods: Sprague-Dawley rats were randomly divided into control group, sham-operation group, model group, and electroacupuncture treatment group, with 12 rats in each group. A rat model of AD was established by injection of Aβ into the bilateral hippocampus. The rats in the electroacupuncture treatment group were given electroacupuncture at "Baihui" (GV20) and "Shenshu" (BL23) once a day, 15 min each time, for 10 days. Morris water maze was used to evaluate learning and memory abilities, immunohistochemistry was used to measure the distribution and expression of P35/P25, CDK5, and Tau5 in the hippocampus, and Western blot was used to measure the expression of the above mentioned proteins, phosphory-lated Tau(Ser199, Ser202).

Results: In the visual platform test, there were no significant differences in escape latency and search path between groups (>0.05). In the hidden platform test, there were no significant differences in escape latency and search path between the control group and the sham-operation group (>0.05); the model group had significantly longer escape latency and search path than the control group and the sham-operation group (<0.05). Compared with the model group, the electroacupuncture treatment group had significantly shorter escape latency and search path (<0.05). In the spatial exploration test, there was no significant difference in the number of platform crossings between the control group and the sham-operation group (<0.05). The model group had a significantly lower number of platform crossings than the control group and the sham-operation group (<0.01, <0.05). The electroacupuncture treatment group had a significantly higher number of platform crossings than the model group (<0.05). Compared with the control group and the sham-operation group, the model group had significant increases in the protein expression of P35/P25 and CDK5 (<0.001), and the electroacupuncture treatment group had significant reductions compared with the model group (<0.001). There was no significant difference in the protein expression of Tau5 between groups (>0.05). The model group had significantly higher protein expression of phosphorylated Tau(Ser199, Ser202) in the hippocampus than the control group and the sham-operation group (<0.01, <0.05). The electroacupuncture treatment group had significantly lower protein expression of phosphorylated Tau(Ser199，Ser202) than the model group (<0.05, <0.01).

Conclusion: Electroacupuncture may delay the progression of AD by affecting the expression of proteins involved in the P35/P25-CDK5-Tau pathway in the hippocampus of rats.