A previous study has demonstrated that pretreatment with electroacupuncture (EA) induces rapid tolerance to focal cerebral ischemia. In the present study, we investigated whether adenosine receptor 1 (A1 R) is involved in EA pretreatment-induced cognitive impairment after focal cerebral ischemia in rats. Two hours after EA pretreatment, focal cerebral ischemia was induced by middle cerebral artery occlusion for 120 min in male Sprague-Dawley rats. The neurobehavioral score, cognitive function [as determined by the Morris water maze (MWM) test], neuronal number, and the Bax/Bcl-2 ratio was evaluated at 24 h after reperfusion in the presence or absence of CCPA (a selective A1 receptor agonist), DPCPX (a selective A1 receptor antagonist) into left lateral ventricle, or A1 short interfering RNA into the hippocampus area. The expression of the A1 receptor in the hippocampus was also investigated. The result showed that EA pretreatment upregulated the neuronal expression of the A1 receptor in the rat hippocampus at 90 min. And EA pretreatment reversed cognitive impairment, improved neurological outcome, and inhibited apoptosis at 24 h after reperfusion. Pretreatment with CCPA could imitate the beneficial effects of EA pretreatment. But the EA pretreatment effects were abolished by DPCPX. Furthermore, A1 receptor protein was reduced by A1 short interfering RNA which attenuated EA pretreatment-induced cognitive impairment.

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.

Electroacupuncture (EA) is widely used in clinical settings to reduce inflammatory pain. Islet-cell autoantigen 69 (ICA69) has been reported to regulate long-lasting hyperalgesia in mice. ICA69 knockout led to reduced protein interacting with C-kinase 1 (PICK1) expression and increased glutamate receptor subunit 2 (GluR2) phosphorylation at Ser880 in spinal dorsal horn. In this study, we evaluated the role of ICA69 in the antihyperalgesic effects of EA and the underlying mechanism through regulation of GluR2 and PICK1 in spinal dorsal horn. Hyperalgesia was induced in mice with subcutaneous plantar injection of complete Freund adjuvant (CFA) to cause inflammatory pain. Electroacupuncture was then applied for 30 minutes every other day after CFA injection. When compared with CFA group, paw withdrawal frequency of CFA+EA group was significantly decreased. Remarkable increases in Ica1 mRNA expression and ICA69 protein levels on the ipsilateral side were detected in the CFA+EA group. ICA69 expression reached the peak value around day 3. More importantly, ICA69 deletion impaired the antihyperalgesic effects of EA on GluR2-p, but PICK1 deletion could not. Injecting ICA69 peptide into the intrathecal space of ICA69-knockout mice mimicked the effects of EA analgesic and inhibited GluR2-p. Electroacupuncture had no effects on the total protein of PICK1 and GluR2. And, EA could increase the formation of ICA69-PICK1 complexes and decrease the amount of PICK1-GluR2 complexes. Our findings indicate that ICA69 mediates the antihyperalgesic effects of EA on CFA-induced inflammatory pain by regulating spinal GluR2 through PICK1 in mice.

BACKGROUND:It has been reported that carnosic acid (CA) exhibits a range of biological activities including hepatoprotective, antioxidant and anti-inflammatory. However, the effect of carnosic acid in neuropathic pain remained elusive. METHODS:A neuropathic pain model of chronic constriction injury (CCI) was established in adult male Sprague-Dawley rats. Mechanical withdrawal threshold (MWT) and thermal withdrawal latency (TWL) were recorded, and western blot was performed to detect sirtuin1 and p66shc content. RESULTS:Intrathecal administration of carnosic acid attenuated mechanical allodynia and thermal hyperalgesia in rats following chronic constriction injury. Interestingly, carnosic acid analgesic effect was positively associated with spinal sirtuin1 activation; however, p66shc was inhibited by carnosic acid in the spinal cord. In additional, sirtuin1 inhibitor EX-527 reversed the anti-nociceptive effect of carnosic acid. CONCLUSIONS:Carnosic acid is effective in the treatment of the established CCI-induced pain. It may be possible that spinal sirtuin1 activition by carnosic acid attenuates neuropathic pain through a mechanism involving the down-regulation of p66shc expression.

Objectives: Cerebral vasospasm (CVS) and early brain injury are major causes of morbidity and mortality following subarachnoid hemorrhage (SAH). We investigated the efficiency of human tissue kallikrein (HTK) to prevent CVS in a rabbit model of SAH.Methods: Forty-eight Japanese white rabbits were randomly divided into four groups (n = 12 each): control (sham-operated), SAH, SAH + phosphate-buffered saline (PBS, vehicle), and SAH + HTK. Basilar artery (BA) diameters were measured by three-dimensional computed tomography angiography at three time points. Endothelin-1 (ET-1) and nitric oxide (NO) levels in the cerebrospinal fluid (CSF) were assayed 24 h before and 5 and 7 days after SAH. After the last measurement, the animals were killed, and endothelial cell apoptosis was assessed. Bax and Bcl-2 levels in the BA were measured by western blotting.Results: HTK was found to significantly reduce CVS following SAH in rabbits. Inverse changes were observed in ET-1 and NO levels in the CSF collected from the SAH group. HTK increased levels of NO, which has a vasodilatory effect, but did not affect levels of ET-1, which has a vasoconstrictive effect. CTA revealed that HTK treatment significantly increased BA diameter. Moreover, HTK treatment reduced the number of apoptotic cells following SAH, presumably by increasing and decreasing Bcl-2 and Bax expression, respectively.Conclusion: HTK ameliorated CVS and inhibited apoptosis in the BA in a rabbit model of SAH.