Effect of electroacupuncture on synaptic ultrastructure and synaptic function related proteins PSD95 and MeCP2 in sleep deprivation rats

To observe the effect of electroacupuncture (EA) on the expression of synaptic function related proteins PSD95 and MeCP2 and synaptic ultrastructure in sleep deprived rats, so as to explore its mechanism underlying improvement of learning and memory ability caused by sleep deprivation.

SD rats were randomly divided into normal, model, EA and sham EA groups (n=10). The sleep deprivation model was prepared by modified multi-platform water environment. Rats of the EA group received EA stimulation at "Baihui" (GV20) and "Dazhui" (GV14), while the sham EA group received shallow needling 4 mm away from the above acupoints without electrical stimulation. The learning and memory ability was evaluated with Morris water maze test. The density of dendritic spines in hippocampal CA1 region was detected by Golgi staining. The synaptic ultrastructure of hippocampus was observed by electron microscope. The protein expression levels of PSD95 and MeCP2 in hippocampus was detected by Western blot.

Compared with the normal group, the escaping latency of the positioning navigation experiment in the model group was prolonged (P < 0.05), the number of crossing the platform and the residence time in the target quadrant were decreased (P < 0.05), the density of dendritic spines in the hippocampal CA1 area was decreased (P < 0.05), the number of synapses was reduced, with swollen synaptosomes, blurred synaptic structure, disappeared and narrowed synaptic clefts, the protein expression levels of PSD95 and MeCP2 were significantly decreased (P < 0.05) in the model group. Compared with the model group, the escape latency of the positioning navigation experiment was shortened (P < 0.05), the number of crossing platforms and the time spent in the target quadrant were increased (P < 0.05), the density of dendritic spines in the hippocampal CA1 region was increased (P < 0.05), the morphology of synaptic improved, the protein expression levels of PSD95 and MeCP2 were increased (P < 0.01) in the EA and sham EA groups. The improvement of the above indexes in EA group was more obvious than those in sham EA group.

EA can improve the learning and memory of sleep deprivation rats, which may be related to its function in regulating the expressions of synaptic related proteins PSD95 and MeCP2, and improving the synaptic structure.