Objective To observe the effect of transcutaneous electrical acupoint stimulation(TEAS) on the histomorphological manifestations of hippocampal CA1 region and the expression of extracellular regulatory protein kinase(ERK)

cyclic adenosine response element binding protein(CREB) and brain-derived neurotrophic factor(BDNF) in chronic fatigue syndrome(CFS) rats

so as to explore the mechanisms of TEAS in improving the learning and memory abilities of CFS rats. Methods Forty male Wistar rats were randomly divided into normal group(10 rats) and modeling group(30 rats); then after modeling

they were selected and randomly divided into model group(10 rats) and TEAS group(10 rats). CFS rats model was prepared by sleep deprivation combined with weight-bearing swimming. Rats in the TEAS group were stimulated with Han's acupoint nerve stimulator at bilateral “Zusanli”(ST36) and “Shenshu”(BL23)(2 Hz/15 Hz

1-2 mA)

20 min each time

once a day for 4 weeks with 1 d rest every 6 d. The score of general conditions of rats was evaluated. The learning and memory ability was tested with Morris water maze. The morphology and ultrastructure of hippocampal CA1 region were observed by HE staining and transmission electron microscopy. The expression levels of ERK

CREB and BDNF mRNAs and proteins in hippocampus were detected by real time quantitative PCR and Western blot

respectively.Results Compared with the normal group

the score of general condition was increased(P

<

0.01); the escape latency was prolonged(P

<

0.05

P

<

0.01) and the times of crossing the original platform was decreased(P

<

0.05); the expression levels of ERK

CREB and BDNF mRNAs and proteins in hippocampus were decreased(P

<

0.05

P

<

0.01) in the model group. Compared with the model group

the scores of general condition on the 42

(nd)

and 49(nd) and 49

(th)

day were decreased(P

<

0.05

P

<

0.01); the escape latency was shortened(P

<

0.01

P

<

0.05)and the times of crossing the original platform were increased(P

<

0.05); the expression levels of ERK

CREB and BDNF mRNAs and proteins in hippocampus were increased(P

<

0.01

P

<

0.05) in the TEAS group. The morphology of neurons in hippocampal CA1 region was normal in the normal group. In the model group

the number of neurons in hippocampal CA1 region decreased

the arrangement of nerve cells was scattered

the number of apoptotic cells increased

some nuclear structures disappeared

nuclear heterochromatin increased

the cell membrane wrinkled

the chromatin appeared empty bright area

and the crista was incomplete. Compared with the model group

the nerve cells morphology in hippocampal CA1 region was more regular

the number of apoptotic cells decreased

the chromatin and the cytoplasm were uniformly distributed

and the crista was relatively intact in the TEAS group. Conclusion TEAS can improve the learning and memory ability of CFS rats

the mechanisms may be related to improving the neural structure of hippocampal CA1 region and up-regulating the expression levels of ERK/CREB/BDNF.