[Study on efficacy specificity of electroacupuncture at "Zusanli "(ST36) and "Baihui" (GV20) in cerebral ischemia and inflammatory pain rats].

OBJECTIVE: To explore the efficacy difference between electroacupuncture (EA) at "Zusanli" (ST36) and "Baihui" (GV20) for inflammatory pain and cerebral ischemia-reperfusion injury (CIRI) in rats. METHODS: In 1st part of this study, 90 male SD rats were randomly divided into sham-operation, model (induced by occlusion of the middle cerebral artery and reperfusion), GV20 EA, ST36 EA，and sham EA groups (n=16 in each group). In the 2nd part of the study, 40 male SD rats were randomized into saline injection (control), inflammatory pain model (subcutaneous injection of complete Freund's adjuvant ［CFA］ into the right paw), ST36 EA, GV20 EA, and sham EA groups (n=8 in each group). In these two parts, EA (2 Hz/15 Hz, 1 mA) was applied to ST36 or GV20. The mechanical withdrawal threshold (MWT) and thermal withdrawal latency （TWL） were detected 2.5 h after administration of CFA by using Von Frey and plantar tester, respectively. The neurological deficit scores (NDS) were assessed by using Longa's method and the infarct size of the brain assessed after staining with 2% triphenyltetrazolium chloride (TTC). The expression of c-fos protein in the dorsal horns (DHs) of the spinal cord was detected by immunohistochemistry. RESULTS: (1) Twenty-four hours following CIRI, the NDS and infarct volume were significantly increased in the model group compared with the sham-operation group (P<0.01), and obviously decreased in the GV20 EA and ST36 EA groups relevant to the CIRI model group (P<0.05, P<0.01). There were no significant differences between the two EA groups in the NDS and infarct volume levels (P>0.05). (2) After administration of CFA, both the MPT and TPT were notably decreased in the inflammatory pain model group in contrast to the saline-injection group (P<0.01), but were considerably increased in both ST36 EA and GV20 EA groups (P<0.05), rather than in the sham EA group (P>0.05). The number of c-fos positive cells was significantly increased in the medial half of I-II and III-IV lamina of DHs in the L4-L6 segments of spinal cord in the inflammatory pain model group relevant to the saline-injection group (P<0.01,P<0.05), and was remarkably decreased in the lamina I-II (not in the deeper lamina) in both ST36 EA and GV20 EA groups (P<0.01), rather than in the sham EA group (P>0.05). No significant differences were found in the number of c-fos positive cells between the ST36 EA and GV20 EA groups (P>0.05). CONCLUSION: Our data do not support the specificity of functions at least between GV20 EA and ST36 EA in both CIRI and inflammatory pain model rats. This is the first study reporting the effect of EA at GV20 for relieving CFA-induced inflammatory pain.

[Effect of transcutaneous electrical acupoint stimulation on pulmonary function and oxidative stress response in lower extremity surgery patients using tourniquet].

OBJECTIVE: To investigate the effect of transcutaneous electrical acupoint stimulation (TEAS) on pulmonary function, superoxide dismutase (SOD) activity, and malondialdehyde (MDA) content in patients using tourniquet after lower extremity surgery. METHODS: A total of 40 patients who underwent lower extremity surgery were equally randomized into control group and TEAS group by using a random number table. All patients underwent lumbar epidural anesthesia combined with block anesthesia. The patients in the TEAS group were given TEAS at Zusanli (ST36) and Sanyinjiao (SP6) beginning from 30 min before surgery to the end of surgery, and those in the control group received TEAS at the same acupoints with minimum current intensity. Mean arterial pressure (MAP) and heart rate (HR) were recorded at each time point (T0: pre-surgery /TEAS, T1: 5 min after anesthesia, T2: 1 min before tourniquet-loosening, T3: 1 min after tourniquet-loosening, T4: 5 min after tourniquet-loosening, and T5: 6 h after tourniquet-loosening). Blood samples (4 mL) was collected from the radial artery before TEAS and 6 h after loosening tourniquet for analyzing blood gas parameters as partial pressure of caron dioxide(PCO2), arterial partial pressure of oxygen (PaO2), alveolar partial pressure of oxygen (PAO2), alveolar-arterial oxygen pressure difference (PA-aDO2) and respiratory index (RI) by using a blood gas analyzer, and plasma SOD activity and MDA content were assayed by using xanthine oxidase method and thiobarbituric acid colorimetry method, respectively. RESULTS: Intra-group comparison showed that compared with T0, a significant increase was found in PA-aDO2 and RI at T5 and a significant reduction in PaO2 and PaO2/ PAO2 (a/A) ratio in the control group (P<0.05), and the same changes in the TEAS group (P<0.05) except a/A ratio. Comparison between two groups showed that at T5, both PaO2 and a/A levels were significantly higher in the TEAS group than in the control group (P<0.05), and both PA-aDO2 and RI levels were obviously lower in the TEAS group than in the control group (P<0.05), suggesting an improvement of the pulmonary function after TEAS. At T5, plasma SOD activity was significantly decreased and plasma MDA content was remarkably increased in the control group relevant to T0 (P<0.05), SOD activity was significantly higher in the TEAS group than in the control group (P<0.05), and MDA content was evidently lower in the TEAS group than in the control group (P<0.05), suggesting a reduction of oxidative stress response after TEAS. CONCLUSION: TEAS at ST36 and SP6 can improve pulmonary function and attenuate oxidative stress response in patients using tourniquet after lower extremity surgery.

Electroacupuncture-induced neuroprotection against focal cerebral ischemia in the rat is mediated by adenosine A1 receptors.

The activation of adenosine A1 receptors is important for protecting against ischemic brain injury and pretreatment with electroacupuncture has been shown to mitigate ischemic brain insult. The aim of this study was to test whether the adenosine A1 receptor mediates electroacupuncture pretreatment-induced neuroprotection against ischemic brain injury. We first performed 30 minutes of electroacupuncture pretreatment at the Baihui acupoint (GV20), delivered with a current of 1 mA, a frequency of 2/15 Hz, and a depth of 1 mm. High-performance liquid chromatography found that adenosine triphosphate and adenosine levels peaked in the cerebral cortex at 15 minutes and 120 minutes after electroacupuncture pretreatment, respectively. We further examined the effect of 15 or 120 minutes electroacupuncture treatment on ischemic brain injury in a rat middle cerebral artery-occlusion model. We found that at 24 hours reperfusion,120 minutes after electroacupuncture pretreatment, but not for 15 minutes, significantly reduced behavioral deficits and infarct volumes. Last, we demonstrated that the protective effect gained by 120 minutes after electroacupuncture treatment before ischemic injury was abolished by pretreatment with the A1-receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine (1 mg/kg, intraperitoneally). Our results suggest that pretreatment with electroacupuncture at the Baihui acupoint elicits protection against transient cerebral ischemia via action at adenosine A1 receptors.