Effects of electroacupuncture with different frequencies on hippocampal neuronal apoptosis and JNK signaling pathway in rats with vascular dementia / 针灸推拿医学（英文版）

ABSTRACT

Objective: To observe the effects of electroacupuncture (EA) with three frequencies (100 Hz, 2 Hz, and 2 Hz/100 Hz) on the apoptosis of neurons and c-Jun N-terminal kinase (JNK) signaling pathway in the hippocampus of rats with vascular dementia (VD), and explore the mechanism of EA intervention for VD. Methods: Fifty male Sprague-Dawley rats were randomly divided into a model group, a sham operation group, a 100 Hz EA group, a 2 Hz EA group, and a 2 Hz/100 Hz EA group, with ten rats in each group. The VD model rats were established by repeated ischemia-reperfusion of bilateral common carotid arteries. The rats in the EA groups received EA intervention at Baihui (GV20), Dazhui (GV14), Geshu (BL17) and Zusanli (ST36), once a day for 14 d. Afterward, Morris water maze was used to examine the learning and memory performances of the rats in each group, hematoxylin-eosin staining to observe the histomorphological changes in the hippocampal CA1 region, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling to test the apoptosis of neurons in the hippocampal CA1 region, and Western blot to detect the protein expression levels of JNK, phosphorylated JNK (p-JNK), Caspase-8, and Caspase-3 in the hippocampus tissue. Results: Compared with the sham operation group, the escape latency of the model group in water maze test was prolonged; the number of crossing the original platform was decreased (P<0.01); the hippocampal neurons were severely damaged and the number of surviving neurons was decreased (P<0.01), whereas the number of apoptotic neurons was increased (P<0.01); the protein expression levels of JNK, p-JNK, Caspase-8, and Caspase-3 in the hippocampus were significantly increased (P<0.01). Compared with the model group, the escape latency of each EA group was significantly shortened; the number of crossing the original platform was significantly increased (P<0.01); the damage of hippocampal neurons was alleviated, the number of surviving neurons was increased (P<0.01), and the number of apoptotic neurons was decreased (P<0.01); the protein expression levels of JNK, p-JNK, Caspase-8, and Caspase-3 in the hippocampus were decreased (P<0.01). The results in the 2 Hz EA group and the 2 Hz/100 Hz EA group were superior to those in the 100 Hz EA group. Conclusion: EA with the three frequencies (100 Hz, 2 Hz, and 2 Hz/100 Hz) can improve the learning and memory performances in VD rats subjected to ischemia-reperfusion, its mechanism may be related to the inhibition of neuronal apoptosis and the regulation of the related protein expression of JNK signaling pathway, and the intervention effects of EA with 2 Hz and 2 Hz/100 Hz are more significant.