Objective To observe the effects of electroacupunture (EA) on the abnormal hypothalamus-pituitary-adrenal (HPA) axis and the expression of hypothalamic corticotropin-releasing factor (CRF) peptides family and CRF receptor (R)1 mRNA in traumatized rats

so as to study its underlying mechanism in improving traumatic injury. Methods Forty male Sprague-Dawley rats were randomly divided into normal control group (n=10)

normal+ EA group (n=10)

surgical trauma (model) group (n=10)

and model+EA group (n=10). Traumatic injury model was established by performing an exploratory laparotomy in the rats under anesthesia. EA (2 Hz/15 Hz

1-2 mA) was administered for 30 min via two stainless steel needles inserted in "Zusanli" (ST 36) and "Sanyinjiao" (SP 6). Serum adrenocorticotropic hormone (ACTH)

corticosterone (Cort)

luteinizing hormone (LH) and testosterone (T) contents were detected by double-antibody radioimmnoassay. Hypothalamic CRF and CRF R1 mRNA expression was assayed by reversed transcription polymerase chain reaction (RT-PCR) technique. Results The serum ACTH concentration decreased significantly in model group (P<0.05) compared with those in normal control and normal+EA groups

and was significantly higher in model+ EA group than that in model group (P<0.05). No significant difference was found between normal control and normal+EA groups in serum ACTH levels (P>0.05). The serum Cort level increased significantly in model group(P<0.05) compared with those in normal control and normal+EA groups

and was obviously lower in mo-del+EA group than that in model group (P<0.05). While serum LH and T contents had no apparent changes in the four groups (P>0.05). The expression of hypothalamic CRF mRNA decreased significantly in model group (P<0.05) compared with that in normal control group

but increased significantly in model+EA group (P<0.05) compared with that in model group. However

no significant difference was found between normal control and normal+EA groups in the CRF mRNA expression level. The expression of hypothalamic Ucn 1 mRNA increased significantly in model group than that in normal control group (P<0.05)

and decreased considerably in model+ EA group than that in model group (P<0.05). There were no significant changes in the expression of hypothalamic Ucn 2 mRNA

Ucn 3 mRNA and CRF R1 mRNA in the four groups (P>0.05). Conclusion EA of "Zusanli" (ST 36) and "Sanyinjiao" (SP 6) can improve surgical trauma-induced HPA disorders

which is probably related to its effects in upregulating CRF mRNA expression and downregulating Ucn 1 mRNA expression in the hypothalamus.