Chronic visceral hyperalgesia and acupuncture to ease the neurobiological mechanisms of visceral pain
|Keywords||Acupuncture analgesia Central sensitization NR1 receptor c-Fos protein Immunohistochemistry Abdominal withdrawal reflex (AWR) Chronic visceral hyperalgesia Spinal dorsal horn Irritable bowel syndrome (IBS) The rostral ventromedial nucleus (RVM) Rats|
Although modern medical science has made great progress, chronic pain clinicians deeply thorny challenge. Chronic pain seriously affect the patient's quality of life, and the efficacy of the treatment of chronic pain is not satisfactory, and the high costs, which consume a large number of medical and social resources. Chronic visceral pain bowel function disorders (such as irritable bowel syndrome, non-cardiac chest pain, chronic indigestion, etc.), as well as one of the main symptoms of pelvic organ disorders (such as chronic interstitial cystitis) . Intestinal tract and pelvic organ disorders lack of anatomical structure, infection, metabolic abnormalities, pain dispersion indicators no fixed sites and easily confused with parenchymal disease of the internal organs. Among the functional disorders of the gastrointestinal tract, IBS patients, the proportion of the largest incidence of about 18-20%. The main symptoms are: abdominal pain, bloating, constipation and / or diarrhea. Similarly, about 15% of women suffer chronic pelvic pain the troubled . Intestinal tract and pelvic organ disorders characterized by lower abdominal pain. There are a variety of factors may cause these dysfunction diseases occur, such as sustained mental stress, organ infection and inflammation history, genetic background, early negative events (such as abuse, trauma and pain, etc.) and the like. In recent years, the study of the pathogenesis of IBS rectal balloon inflated test, IBS patients and IBS animal models pain threshold was significantly lower than the control group, that is visceral hyperalgesia phenomenon, visceral hyperalgesia may IBS patients with chronic abdominal pain and discomfort. one of the main mechanisms. Generally believed that visceral hyperalgesia may be associated with visceral afferent nerve and the nerve center of the phenomenon of sensitization (sensitization). Of animal and human studies have shown that the three central mechanisms may be involved in the modulation of visceral hyperalgesia: 1) brain nerve center of the visceral sensory conduction easily effect; 2) consecutive visceral afferent information stimulation due to spinal cord sensorium in the sensitized state; 3) from the marrow on to facilitate adjustment of the center of the spinal cord or internal organs sensory transmission. The spinal cord is the first stage after the integration of the pain signal into the center hub, the pain of information transmission of the relay station, both the direct modulation of pain, but also accept supraspinal central downlink adjustment signal, painful stimulus to adjust the key parts. A large number of studies have shown that many neurotransmitters, receptors, cytokines play a key role in the peripheral and central mechanisms of hyperalgesia formed spinal dorsal horn, which include the 5-HT, P substance and calcitonin gene-related peptide (CGRP) also including the NMDA receptor. The rostral ventromedial nucleus (RVM) is a common pathway of the spinal cord on the nerve center of the downlink modulation of visceral nociceptive stimulation. The RVM has dual regulation of visceral pain: rejection and ease of harm input. According to a large number of research results, Porreca et al hypothesized, RVM downlink information for pain regulation disorders, pain, paresthesia important reason such as IBS, fibromyalgia and neuropathic pain, glutamic acid neurotransmitters and their receptors in the RVM especially NMDA receptors, play an important role in acupuncture analgesia in the regulation of visceral hyperalgesia is one of the treasures of Chinese medicine, efficacy, fewer side effects, and simple economic advantages. The large number of domestic and international clinical and basic studies have shown that acupuncture treatment of various types of pain, including visceral pain has a significant analgesic effect. Is generally believed by the multiple nerve center on the spinal cord, such as RVM, PAG, amygdala, cingulate downlink of pain modulation system has a strong inhibitory effect on the conduction of the dorsal horn of the spinal cord pain information, acupuncture may activate downlink pain modulation system and play its analgesic effect. Al-Chaer, reported in 2001, a way to simulate the clinical IBS in a rat model. Successfully copied the IBS rat model to observe the electrical role in the treatment of irritable bowel syndrome, found that EA could significantly alleviate the rat model of chronic visceral hyperalgesia, and found that the electricity for the of IBS rat chronic visceral pain the sensitive treatment effect, probably by central NMDA receptors play a role. For acupuncture treatment to alleviate IBS rat model chronic visceral hyperalgesia role of the mechanism, however, has yet to be further carried out. In view of the formation and development of chronic visceral pain and spinal cord and RVM glutamate neurotransmitter receptor systems are closely linked, EA could significantly alleviate the rat model of chronic visceral hyperalgesia, and found that the electrical treatment effect for chronic visceral hyperalgesia the possible central NMDA receptors play a role, this study selected the spinal cord dorsal horn and RVM in c-Fos and NR1 receptor study, using immunohistochemical methods, observation and analysis of the IBS rat spinal cord dorsal horn and RVM visceral reaction to the excitability of the neurons in the acupuncture treatment before and after the change, as well as the two in the NR1 receptor acupuncture to ease IBS rat model of chronic visceral hyperalgesia in participatory mechanisms. Method 1. Establish IBS rat model reference to Al-Chaer rat IBS model and our research group reported improvement, nine days of newborn SD rats were divided into two groups, the first group of colorectal mechanical expansion to stimulate the production of IBS chronic visceral hyperalgesia model, two weeks; another group only gentle perianal skin as a control. After 2.IBS model behavior in rats assessment reared to 6 to 8 weeks, respectively, through the determination of rat model of abdominal withdrawal reflex (abdominal withdrawal reflex AWR) and pain threshold pressure value (pain threshold pressure, PTP), model assessment. IBS rat model of electro-acupuncture treatment and behavioral assessment of treatment outcomes IBS rat model randomly divided into three groups: the model group (M) the model plus EA group (EA) and model plus sham EA group ( SEA). Model group without any treatment, the the EA group points take bilateral \Again through behavioral assessment of the electric needle treatment results. 4. Fixed and frozen sections of rats were prepared in 5% pentobarbital anesthesia, about perfusion with 4% paraformaldehyde for 30 min, medullary and spinal gradient of sucrose in PBS and dehydration, after it is made of 30μm consecutive frozen sections were placed in 24-well plates of different markers. 5 observed several EA process spinal cord T13-L2 and L6-S2 segments, as well as the RVM of c-Fos of protein and NRl receptor expression variation of 5.1 using immunohistochemistry to observe the spinal cord T13-L2 and L6-S2 segment and RVM in c-Fos protein expression observed for these parts of the IBS rat model visceral reaction neuron excitability. 5.2 using immunohistochemical methods, observe Spinal Cord L6-S2 segments and RVM NR1 receptor expression, the observed variation of these parts after several EA IBS rat model of NMDA receptor expression. Results 1.IBS rat PTP value decreased AWR score abnormally elevated compared with the positive control group, model group decreased value of PTP. AWR scores results show that the model group compared to the normal control group, AWR score was significantly higher in the different intensity (20,40,60,80 mmHg) CRD induced visceral pain stimulation. 2. Electro-acupuncture to ease IBS rat visceral hyperalgesia EA group after treatment compared to before treatment and sham EA group therapy, AWR score was significantly lower, PTP was significantly higher, while sham EA group after treatment and before treatment AWR scores the difference was not statistically significant. 3.IBS rat spinal cord dorsal horn c-Fos, and NRl receptor expression was significantly higher in the CRD stimulus, relative to the control rats, IBS model rats L6-S2 segments shallow (the superficial lamina SDH, lamina Ⅰ and Ⅱ), intrinsic layer (T nucleus of proprius NP lamina Ⅲ and Ⅳ), the dorsal horn of the cervical (the neck of the dorsal horn, NECK, laminae Ⅴ and Ⅵ), c-FosI positive nerve yuan was significantly higher than the normal control group, while in the X layer is no significant difference; IBS rat model T13-L2 segments in addition of c-Fos positive neurons in the dorsal horn the NECK layers (laminae V), significantly higher than higher than compared to the normal control rats the superficial lamina propria and central peritubular area c-Fos positive neurons were no significant differences. Receptor NR1 staining results similar to the results of the c-Fos, L6-S2 segments shallow IBS model group, the lamina propria of the number of neurons and IOD positive F value is significantly higher than normal control group. Of 4.IBS model in rats RVM of c-Fos and NR1 receptor expression was significantly elevated in the RVM various the subnuclear Gi (nucleus of reticularis gigantocellularis), the blood gas analysis was tested after 12 days (nucleus of lateralis paragigantocellulari) GiA (nucleus of the reticularis gigantocellularis pars alpha), NRM ( nucleus raphe magnus) the level of c-Fos, IBS model group and NR1 receptor immunoreactive cell count was significantly higher: the RVM in NR1 receptor IOD values ??and normal control group was significantly higher compared. 5. Electro-acupuncture significantly reduced c-Fos and NR1 receptor expression in the IBS model rat spinal cord dorsal horn several times the next day after electro-acupuncture treatment, IBS model rats L6-S2 segments SDH, NP, NECK, X-layer c-Fos positive neurons decreased sham EA does not have this effect. Electroacupuncture treatment of IBS rat T13-L2 segment of the superficial lamina propria, c-Fos positive neurons of the dorsal horn of the cervical and central peritubular area was no significant difference in the number; several times the next day after electro-acupuncture treatment, IBS model rat L6-S2 segments SDH, NP, NR1 positive neurons number and IOD value decreased NECK layer, NR1 positive neurons was no significant difference in the number of, IOD values ??decreased to sham EA does not have this effect. 6. Electro-acupuncture significantly reduced IBS rat model RVM in c-Fos and NRI receptor expression IBS model rats after treatment in four consecutive EA RVM subnuclear Gi, the blood gas analysis was tested after 12 days, GiA c-Fos protein, as well as Gi, LPGi, GiA, NRM NR1 receptor immunoreactive cell count decreased; RVM overall level of NR1 receptor the IOD value also significantly decreased. But no significant change compared to sham EA group and the model group. In summary, this study suggests that: PTP AWR scores showed that adult rats of IBS model of visceral hyperalgesia obvious visceral hypersensitivity and hyperalgesia phenomenon simulated clinical IBS patients with gut hypersensitivity phenomenon a relatively stable chronic visceral hyperalgesia animal models. 2, our early laboratory research results show that the EA 4-6 times every other day, to achieve the maximum therapeutic effect. This study suggests that the fourth EA treatment, PTP and AWR scores show that multiple EA treatment can significantly alleviate chronic visceral hyperalgesia. IBS rat model L6-S2 segments of the spinal cord dorsal horn and RVM in c-Fos protein expression was significantly higher in the visceral reaction in this table, the huge amount of spinal cord dorsal horn and RVM neuronal excitability abnormal increase may IBS rat model an important cause of visceral hyperalgesia. 4, IBS model rat spinal dorsal angle and RVM in NR1 receptor expression was significantly elevated, suggesting that the spinal cord dorsal horn and RVM visceral reaction to abnormal expression of NR1 receptor neurons, may be involved in IBS rat model of chronic visceral functional to maintain HYPERALGESIA. 5, acupuncture can significantly inhibit IBS rat model L6-S2 segments of the spinal cord dorsal horn and RVM in c-Fos expression, so that the spinal cord dorsal visceral reaction in the corner and RVM neuron abnormalities increased excitability decline, which may be acupuncture 6, electro-acupuncture can significantly inhibit IBS rat model of spinal cord dorsal horn and RVM NR1 receptor expression, which may be visceral reaction in the spinal cord dorsal horn and RVM neurons abnormally high levels of the excitatory decline alleviate one of the mechanisms of chronic visceral hyperalgesia important reason for this may be one of the mechanisms of acupuncture to ease chronic visceral hyperalgesia.