[The role of adenosine deaminase in the electroacupuncture preconditioning induced rapid tolerance to focal cerebral ischemia].

OBJECTIVE

To observe the electroacupuncture (EA) pretreatment at Baihui (GV20) on the concentration of adenosine deaminase (ADA) and adenosine, and to evaluate its effects on the neurologic function score and the infarction volume after middle cerebral artery occlusion (MCAO) ischemia/reperfusion (I/R), thus exploring its mechanisms for relieving the ischemia/reperfusion injury.

METHODS

Totally 54 male SD rats were randomly divided into 3 groups, the sham-EA group, the EA group, and the control group, 18 in each group. Rats in the control group were not intervened after anesthesia. Rats in the EA group were needled at Baihui (GV20) for 30 min. Rats in the sham-EA group received the same procedure as those performed in the EA group without electricity connected. The changes of adenosine and ADA contents were detected at 30, 60, and 120 min after EA respectively. The I/R model was established. Totally 48 male SD rats were randomly divided into 6 groups, i.e., the model group (Group A), the EA group (Group B), the EA +8-Cyclopentyl-1,3-dipropylxanthine (DPCPX) group (Group C), the EA + DMSO group (Group D), the Deoxycoformycin (Deo) group (Group E), and the normal saline group (Group F). Rats in Group B, C, and D received EA for 30 min before modeling. Rats in Group C and D were peritoneally injected with DPCPX (1 mg/kg) and DMSO (1 mL/kg) at 30 min before EA. The neurologic function score was evaluated and the infarct volumes were detected after 24-h reperfusion.

RESULTS

Compared with the sham-EA group, there was no statistical difference in the contents of the adenosine or ADA in the control group at each time point (P > 0.05). Compared with the control group at the same time point, the content of ADA significantly decreased at 60 min in the EA group [(315.0 +/- 22.9 U/L), P < 0.05], and restored to the normal level at 120 min after EA. The content of adenosine increased in the EA group at 120 min [(20.4 +/- 2.2) ng/microL, P < 0.05]. Compared with the model group, the neurologic function score decreased (P < 0.05) and the infarct volumes were obviously reduced (P < 0.01) in Group B, D and E. There was no statistical difference in the neurologic function score or the infarct volumes in other groups, when compared with the model group (P > 0.05)

CONCLUSION

EA at Baihui (GV20) showed protective effects on the cerebral I/R rats, which might be achieved through lowering the ADA concentration and elevating the adenosine content, and further activating adenosine A1 receptor.