The Effect of Electroacupuncture on Changes of the Phosphorylation of Capsaicin Receptor in Chronic Morphine Tolerance Rats and the Mechanism of Electroacupuncture
|School||Tianjin Medical University|
|Keywords||Electro-acupuncture Morphine tolerance Capsaicin receptor Phosphorylation Dorsal root ganglion ERK CREB|
Opioids are important drug for the treatment of acute and chronic pain, but long-term use can be tolerated phenomenon occurs, thereby limiting the clinical application of opioids. Therefore, the opioid tolerance of the cellular and molecular mechanisms and clinical interventions become the focus of research in recent years. 1997 cloned capsaicin receptor (VRl, TRPV1) is considered to be the integration of tissue trauma and inflammation caused by a variety of painful stimuli. A lot of evidence that capsaicin receptors directly involved in the formation of inflammatory hyperalgesia. Acupuncture analgesia is a treasure of traditional medicine, clinical practice confirmed that electro-acupuncture and acupuncture analgesia is an effective analgesic. The study of the mechanism of acupuncture analgesia is the current hot topic of pain research at home and abroad. In this study, arthritis morphine tolerance in the rat model-based, focused on electricity for chronic morphine tolerant rats capsaicin receptor phosphorylation change as well as the mechanism of action of the EA. Expect the results of these studies will provide important information related morphine tolerance treatment and research in the future. The first part: The purpose of inflammatory pain - morphine tolerance complex electro-acupuncture stimulation model and electrical changes in phosphorylation of capsaicin receptor: the establishment of inflammatory pain - morphine tolerance and composite EA stimulation model to study the different frequency electricity for morphine tolerance and rat vanilloid receptor (TRPV1) phosphorylation. Methods Male SD rats, weighing 250-280g, foramen magnum line intrathecal catheter, catheter successful rat right hind ankle 50μl injection of complete Freund's adjuvant made the rats with adjuvant arthritis model were randomly divided into four groups (n = 5): the intrathecal saline 10μl control group (N), morphine 10μg group (M), morphine 10μg low-frequency electro-acupuncture 2Hz group (H group), morphine 10μg high-frequency electric needle 15Hz group (I group), three days after inflammation intrathecal administration, the administration of each group are twice a day (8:00 and 8:00), for seven consecutive days. H and group Ⅰ morphine for the first time on a daily basis to give 2mA 2Hz and 2mA, 15Hz, EA, once a day, every 30min. Dynamic detection rats 50% mechanical paw withdrawal threshold and hot plate paw withdrawal latency, to the hyperalgesia form as morphine tolerance established flag. Taken in the first eight days of the administration of the rats in each group L4-5 dorsal root ganglion Western blot analysis, observation groups in rat dorsal root ganglion TRPV1 protein expression and phosphorylation of TRPV1 strip results using Quantity One software with gray value analysis. Results of each group of rats with mechanical allodynia and thermal hyperalgesia value: compared with proinflammatory after inflammation pain threshold of rats in each group were significantly lower pain threshold of the saline control group were given saline 7 days did not change obvious; morphine rats after administration of morphine first manifested as increased pain threshold, and then gradually reduce the seven days of the administration of pain threshold significantly decreased compared to baseline values ??(P lt; 0.05). H I rats compared with 3 days 5 days of the administration, the administration seven days compared with five days, pain threshold difference was not statistically significant, and are higher than the M group. The H rats pain threshold is higher than I rats. Morphine group capsaicin receptor phosphorylation level of the highest, with the other three groups differences were statistically significant (P lt; 0.05), H group capsaicin receptor phosphorylation express at least H groups, group I phosphorylation of capsaicin by The body expression significant difference (P lt; 0.05). The conclusion can be successfully established by repeated injections of arthritic rats intrathecal morphine, morphine tolerance model. The low-frequency the 2Hz electric needle can significantly reduce the capsaicin receptor TRPV1 phosphorylation, inhibiting the formation of morphine tolerance the, 15Hz electric needle role than 2Hz EA significantly. The second part: EA alleviate morphine tolerance mechanism to explore purpose: To investigate the role of of MAPK ERK / CREB signaling pathways in the electro-acupuncture treatment, research electro-acupuncture to relieve morphine tolerance mechanism. Methods: Using immunohistochemistry, western-blot method for detecting the packet in the control group (N), morphine group (M) and low-frequency electro-acupuncture group (H) in rat dorsal root ganglion phosphorylation of CREB and ERK1 / 2 expression. Results: Compared with the control group, morphine group rat dorsal root ganglion CREB and ERK1 / 2 expression increased, the difference was statistically significant; compared with the morphine group, the low-frequency electro-acupuncture group rat dorsal root ganglion CREB and ERK1 / 2 levels were significantly reduced. Conclusion: ERK-CREB signaling pathways involved in the mitigation effect of electroacupuncture on morphine tolerance.