Autologous fat grafting to the paravertebral space seems to prevent the postherpetic neuralgia-A single-arm pilot study.

INTRODUCTION: Postherpetic neuralgia (PHN) is one of the most common complications of Herpes zoster (HZ), yet the mechanism and the treatment for PHN remains elusive. We first performed this feasibility study to verify the safety and efficiency of autologous fat grafting into the paravertebral space in early HZ to prevent PHN. METHODS: Patients suffering from HZ with a rash in chest, back, or abdomen were arranged for autologous fat grafting to the paravertebral space. The primary endpoint was the incidence of PHN, which was defined as persistence pain in the affected dermal area in 12 weeks after fat grafting. Secondary endpoints including patient-reported changes in pain intensity, assessed pain threshold and the quality of life during follow-ups. RESULTS: Eight patients accept the intervention and completed all follow-ups. Most patients report immediate pain relief after injection, one patient has a mild to moderate dizzy symptom after injection. No other short- or long-term adverse events occurred. For primary outcome, all patients have a timely reduced pain intensity, with no PHN events occurred, as all patients report pain intensity ≤3 in the VAS scale in 3 months after treatment. For electrical pain threshold, we identify that fat grafting differentially increases sensation and pain threshold in HZ area and healthy skin of patients. Besides, our results indicate significant improvement in patients' life quality decrease in analgesic consumption. DISCUSSION: Autologous fat transplantation to the paravertebral space is a safe and feasible technique in preventing PHN from HZ in a rash. Further randomized controlled trial to investigate the actual long-term benefice of autologous fat grafting to the paravertebral space in preventing PHN is needed. TRIAL REGISTRATION: ChiCTR, (ChiCTR1900025416); registered August 26, 2019.

Effects of Hypovitaminosis D on Preoperative Pain Threshold and Perioperative Opioid Use in Colorectal Cancer Surgery: A Cohort Study.

BACKGROUND: Postoperative pain after colorectal cancer surgery has a significant impact on postoperative physical and mental health. Vitamin D deficiency has been correlated with both acute pain states, including postoperative and post-traumatic pain, and several chronic pain diseases. The effects of hypovitaminosis D on preoperative pain threshold and perioperative opioid use in colorectal cancer surgery still need to be studied. OBJECTIVES: To find the relationship between hypovitaminosis D on pain threshold, perioperative opioid use, and postoperative complications in colorectal cancer surgery. STUDY DESIGN: A total of 112 patients, who were enrolled in this prospective, observational trial, were divided into 2 groups based on their preoperative serum 25-hydroxyvitamin D (25 [OH] D3) levels: (1) group D: vitamin D-deficient group (< 20 ng/mL); and (2) group S: vitamin D-sufficient group (>= 20 ng/mL). METHODS: Primary outcomes were pain threshold indexes, perioperative dosages of opioid use, and postoperative pain. Secondary outcomes were other postoperative complications. RESULTS: Preoperative serum level of vitamin D was 14.94 ± 3.10 ng/mL in group D and 24.20 ± 4.80 ng/mL in group S. Significant differences were showed in the 3 indexes of pain threshold and analgesic consumption between the 2 groups (P < 0.05). A low 25 (OH) D3 level was associated with a higher opioid dose of sufentanil. There was an association between 25 (OH) D3 and pain enduring threshold (PET), beta coefficient beta = 0.532, 95% confidential interval  (0.440, 0.623), P < 0.001. The history of diabetes mellitus (DM) and vitamin C and vitamin D levels may be risk factors of surgical site infections (SSI), and the binary logistics regression model is statistically significant, chi-squared = 35.028, P < 0.001. LIMITATIONS: There is room for further expansion in the sample size. Our study lacked objective indicators to measure pain threshold. Intestinal recovery time and total hospital stay were not included in the final analysis. In the follow-up study, the vitamin D supplementation group should be set and the specific site of colorectal cancer surgery also needs to be divided more carefully. CONCLUSIONS: On the basis of the study results, hypovitaminosis D is associated with increased perioperative opioid consumption in colorectal cancer surgery. Sensory perception and pain threshold of patients with insufficient 25 (OH) D3 concentration were more sensitive, and PET was lower. History of DM, vitamin D, and vitamin C may be factors related with SSI. Future studies are needed to investigate their relationship further and discover if postoperative pain and pain threshold can benefit from vitamin D supplementation in these patients.

Metformin Relieves Bortezomib-Induced Neuropathic Pain by Regulating AMPKa2-Mediated Autophagy in the Spinal Dorsal Horn.

Chemotherapy-induced neuropathic pain is a major clinical problem with limited treatment options. Here, we show that metformin relieves bortezomib (BTZ)-evoked induction and maintenance of neuropathic pain by preventing the reduction in the expression of Beclin-1, an autophagy marker, in the spinal dorsal horn. Application of rapamycin or 3-methyladenine, autophagy inducer and inhibitor, respectively, affected the mechanical allodynia differently. Co-application of 3-methyladenine and metformin partially inhibited the effect of metformin in recovering Beclin-1 expression and in reducing the pain behavior in rats subjected to BTZ treatment. BTZ treatment also reduced the expression of AMPKa2 in the dorsal horn, which was recovered by metformin treatment. Overexpression of AMPKa2 attenuated the BTZ-evoked reduction in Beclin-1 expression and mechanical allodynia, whereas intrathecal injection of AMPKa2 siRNA decreased the Beclin-1 expression and induced mechanical allodynia in naive rats. Moreover, BTZ treatment increased the GATA3 expression in the dorsal horn, and GATA3 siRNA attenuated the AMPKa2 downregulation and mechanical allodynia induced by BTZ. Chromatin immunoprecipitation further showed that BTZ induced an increased recruitment of GATA3 to multiple sites in the AMPKa2 promoter region. Furthermore, decreased acetylation and increased methylation of histone H3 in the AMPKa2 promoter in the spinal dorsal horn was detected after BTZ treatment. Our findings suggest that metformin may regulate AMPKa2-mediated autophagy in the dorsal horn and alleviate the behavioral hypersensitivity induced by BTZ.

MiR-30d Participates in Vincristine-Induced Neuropathic Pain by Down-Regulating GAD67.

Vincristine is a common chemotherapeutic agent in cancer treatment, while it often causes chemotherapy-induced peripheral neuropathy(CIPN), which brings patients a great disease burden and associated economic pressure. The mechanism under CIPN remains mostly unknown. The previous study has shown that cell-type-specific spinal synaptic plasticity in the dorsal horn plays a pivotal role in neuropathic pain. Downregulation of GABA transmission, which mainly acts as an inhibitory pathway, has been reported in the growing number of research. Our present study found that GAD67, responsible for > 90% of basal GABA synthesis, is down-regulated, while its relative mRNA remains unchanged in vincristine-induced neuropathy. Considering microRNAs (miRNAs) as a post-transcription modifier by degrading targeted mRNA or repressing mRNA translation, we performed genome-wide miRNA screening and revealed that miR-30d might contribute to GAD67 down-regulation. Further investigation confirmed that miR-30d could affect the fluorescence activity of GAD67 by binding to the 3 'UTR of the GAD67 gene, and intrathecal injection of miR-30d antagomir increased the expression of GAD67, partially rescued vincristine-induced thermal hyperalgesia and mechanical allodynia. In summary, our study revealed the molecule interactions of GAD67 and miR-30d in CIPN, which has not previously been discussed in the literature. The results give more profound insight into understanding the CIPN mechanism and hopefully helps pain control.

Exercise for Neuropathic Pain: A Systematic Review and Expert Consensus.

Background: Neuropathic pain (NP), a severe and disruptive symptom following many diseases, normally restricts patients' physical functions and leads to anxiety and depression. As an economical and effective therapy, exercise may be helpful in NP management. However, few guidelines and reviews focused on exercise therapy for NP associated with specific diseases. The study aimed to summarize the effectiveness and efficacy of exercise for various diseases with NP supported by evidence, describe expert recommendations for NP from different causes, and inform policymakers of the guidelines. Design: A systematic review and expert consensus. Methods: A systematic search was conducted in PubMed. We included systematic review and meta-analysis, randomized controlled trials (RCTs), which assessed patients with NP. Studies involved exercise intervention and outcome included pain intensity at least. Physiotherapy Evidence Database and the Assessment of Multiple Systematic reviews tool were used to grade the quality assessment of the included RCTs and systematic reviews, respectively. The final grades of recommendation were based on strength of evidence and a consensus discussion of results of Delphi rounds by the Delphi consensus panel including 21 experts from the Chinese Association of Rehabilitation Medicine. Results: Eight systematic reviews and 21 RCTs fulfilled all of the inclusion criteria and were included, which were used to create the 10 evidence-based consensus statements. The 10 expert recommendations regarding exercise for NP symptoms were relevant to the following 10 different diseases: spinal cord injury, stroke, multiple sclerosis, Parkinson's disease, cervical radiculopathy, sciatica, diabetic neuropathy, chemotherapy-induced peripheral neuropathy, HIV/AIDS, and surgery, respectively. The exercise recommended in the expert consensus involved but was not limited to muscle stretching, strengthening/resistance exercise, aerobic exercise, motor control/stabilization training and mind-body exercise (Tai Chi and yoga). Conclusions: Based on the available evidence, exercise is helpful to alleviate NP intensity. Therefore, these expert consensuses recommend that proper exercise programs can be considered as an effective alternative treatment or complementary therapy for most patients with NP. The expert consensus provided medical staff and policymakers with applicable recommendations for the formulation of exercise prescription for NP. This consensus statement will require regular updates after five-ten years.

ZEB1 Induces Ddr1 Promoter Hypermethylation and Contributes to the Chronic Pain in Spinal Cord in Rats Following Oxaliplatin Treatment.

Application of chemotherapeutic oxaliplatin represses gene transcription through induction of DNA methylation, which may contribute to oxaliplatin-induced chronic pain. Here, Ddr1, which showed an increased methylation in the promoter, was screened from the SRA methylation database (PRJNA587622) after oxaliplatin treatment. qPCR and MeDIP assays verified that oxaliplatin treatment increased the methylation in Ddr1 promoter region and decreased the expression of DDR1 in the neurons of spinal dorsal horn. In addition, overexpression of DDR1 by intraspinal injection of AAV-hSyn-Ddr1 significantly alleviated the mechanical allodynia induced by oxaliplatin. Furthermore, we found that oxaliplatin treatment increased the expression of DNMT3b and ZEB1 in dorsal horn neurons, and promoted the interaction between DNMT3b and ZEB1. Intrathecal injection of ZEB1 siRNA inhibited the enhanced recruitment of DNMT3b and the hypermethylation in Ddr1 promoter induced by oxaliplatin. Finally, ZEB1 siRNA rescued the DDR1 downregulation and mechanical allodynia induced by oxaliplatin. In conclusion, these results suggested that the ZEB1 recruited DNMT3b to the Ddr1 promoter, which induced the DDR1 downregulation and contributed to the oxaliplatin-induced chronic pain.

Chinese Association for the Study of Pain: Expert consensus on chronic postsurgical pain.

Chronic postsurgical pain is a common surgical complication that severely reduces a patient's quality of life. Many perioperative interventions and management strategies have been developed for reducing and managing chronic postsurgical pain. Under the leadership of the Chinese Association for the Study of Pain, an editorial committee was formed for chronic postsurgical pain diagnosis and treatment by experts in relevant fields. The editorial committee composed the main content and framework of this consensus and established a working group. The working group conducted literature review (1989-2020) using key words such as "surgery", "post-surgical", "post-operative", "pain", "chronic", and "persistent" in different databases including MEDLINE, EMBASE, PubMed, Cochrane Central Register of Controlled Trials and Cochrane Database of Systematic Reviews. Only publications in the English language were included. The types of literature included systematic reviews, randomized controlled studies, cohort studies and case reports. This consensus was written based on clinical practice combined with literature evidence. The first draft of the consensus was rigorously reviewed and edited by all the editorial committee experts before being finalized. The level of evidence was assessed by methodological experts based on the Oxford Centre for Evidence-Based Medicine Levels of Evidence. The strength of recommendation was evaluated by all editorial committee experts, and the opinions of most experts were adopted as the final decision. The recommendation level "strong" generally refers to recommendations based on high-level evidence and consistency between clinical behavior and expected results. The recommendation level "weak" generally refers to the uncertainty between clinical behavior and expected results based on low-level evidence.

DNMT3b SUMOylation Mediated MMP-2 Upregulation Contribute to Paclitaxel Induced Neuropathic Pain.

Paclitaxel is a common chemotherapeutic agent in cancer treatment, while it often causes chemotherapy-induced peripheral neuropathy (CIPN), which manifested as hyperalgesia and allodynia, and its mechanism remains largely unknown. The previous study has shown that matrix metalloproteinase-2 (MMP-2) plays a pivotal role in spinal nerve ligation (SNL) induced neuropathic pain, but its function in CIPN and exact molecular mechanisms underlying upregulation is not explored. Our present study revealed that MMP-2 is also upregulated in paclitaxel induced neuropathic pain (NP), and knockdown it by siRNA can ameliorate mechanical allodynia. Since DNA methylation is closely related to gene transcription, we explored the methylation status of the MMP-2 gene and demonstrated that MMP-2 upregulation is related to the reduced methylation level of its promoter. DNA methylation is mediated by DNA methyltransferases (DNMTs), and previous studies suggested that three main types of DNMTs can undergo SUMOylation. Our next study revealed that SUMO1 modification of DNMT3b is significantly enhanced. Intrathecal administration of SUMOylation inhibitor, ginkgolic acid (GA), could reverse enhanced SUMO1 modification of DNMT3b and upregulation of MMP-2 in the model rats. Further investigation suggested that DNMT3b binding activity to the promoter region of the MMP-2 gene is significantly decreased in paclitaxel treated rats, and the administration of GA can reverse these effects, which is also accompanied by changes in the promoter methylation status of the MMP-2 gene. Our study demonstrates that MMP-2 up-regulation mediated by DNMT3b SUMOylation is essential for paclitaxel induced NP development, which brings us new therapeutic options for CIPN.

NFATc2-dependent epigenetic upregulation of CXCL14 is involved in the development of neuropathic pain induced by paclitaxel.

BACKGROUND: The major dose-limiting toxicity of paclitaxel, one of the most commonly used drugs to treat solid tumor, is painful neuropathy. However, the molecular mechanisms underlying paclitaxel-induced painful neuropathy are largely unclarified. METHODS: Paw withdrawal threshold was measured in the rats following intraperitoneal injection of paclitaxel. The qPCR, western blotting, protein or chromatin immunoprecipitation, ChIP-seq identification of NFATc2 binding sites, and microarray analysis were performed to explore the molecular mechanism. RESULTS: We found that paclitaxel treatment increased the nuclear expression of NFATc2 in the spinal dorsal horn, and knockdown of NFATc2 with NFATc2 siRNA significantly attenuated the mechanical allodynia induced by paclitaxel. Further binding site analysis utilizing ChIP-seq assay combining with gene expression profile revealed a shift of NFATc2 binding site closer to TTS of target genes in dorsal horn after paclitaxel treatment. We further found that NFATc2 occupancy may directly upregulate the chemokine CXCL14 expression in dorsal horn, which was mediated by enhanced interaction between NFATc2 and p300 and consequently increased acetylation of histone H4 in CXCL14 promoter region. Also, knockdown of CXCL14 in dorsal horn significantly attenuated mechanical allodynia induced by paclitaxel. CONCLUSION: These results suggested that enhanced interaction between p300 and NFATc2 mediated the epigenetic upregulation of CXCL14 in the spinal dorsal horn, which contributed to the chemotherapeutic paclitaxel-induced chronic pain.

The role of dorsal root ganglia PIM1 in peripheral nerve injury-induced neuropathic pain.

Neuropathic pain induced by peripheral nerve injury is a complex and chronic state that is accompanied by poor quality of life. However, whether PIM1 (proviral integration site 1) contributes to the development of nociceptive hypersensitivity induced by nerve injury remains unknown. The present study was designed to investigate the effects of PIM1 on spinal nerve ligation (SNL) induced pain hypersensitivity. Here, we found that PIM1 positive neurons in the dorsal root ganglion (DRG) were colocalized with nociceptive neuronal markers CGRP, IB4 and substance P and were upregulated after SNL surgery. Knockdown PIM1 in the DRG by AAV5-shPIM1 alleviated SNL-induced pain hypersensitivity. In neuroblastoma cells (neuro-2a), PIM1 regulated the expression of CXCR4 phosphorylated at ser339 (pCXCR4) as well as the CXCL12/CXCR4 pathway. In the DRG tissues, we found that PIM1 was co-expressed with CXCR4, and knockdown of PIM1 attenuated pCXCR4 (ser339) protein expression but had little effect on total CXCR4 protein expression after SNL surgery. These findings suggest that PIM1 contributes to nerve injury-induced nociceptive hypersensitivity. Based on these findings and the characteristics of PIM1, we speculate that PIM1 might be a viable therapeutic target for the treatment of neuropathic pain in the near future.

Up-Regulation of CX3CL1 via STAT3 Contributes to SMIR-Induced Chronic Postsurgical Pain.

Chronic postsurgical pain (CPSP) often occurs after surgery and has a strong impact on patients' daily lives. However, the underlying mechanism of CPSP remains unknown. Here, we used a skin/muscle incision and retraction (SMIR) model to investigate the role of CX3CL1 in SMIR-induced pain and its underlying mechanism. We found that up-regulation of CX3CL1 in the spinal dorsal horn contributed to SMIR-induced mechanical allodynia. The use of a CX3CL1-neutralizing antibody to block CX3CL1 attenuated mechanical allodynia induced by SMIR surgery. We also found that phospho-STAT3 co-localizes with CX3CL1 in spinal neurons after SMIR surgery and that this contributes to SMIR-induced mechanical allodynia. Intrathecal administration of the STAT3 inhibitor S3I-201 suppressed up-regulation of CX3CL1 at both the protein and mRNA levels after SMIR surgery. Chromatin immunoprecipitation further demonstrated that SMIR promotes the recruitment of STAT3 to the cx3cl1 gene promoter (- 1032/- 1022). These findings suggest that activation of STAT3 after SMIR mediates the up-regulation of CX3CL1, leading to mechanical allodynia, and that this upregulation may partly be due to the enhanced recruitment of STAT3 to the cx3cl1 gene promoter after SMIR.

The Diagnosis and Therapy of Degenerative Knee Joint Disease: Expert Consensus from the Chinese Pain Medicine Panel.

At present, there are many constantly updated guidelines and consensuses on the diagnosis and treatment of osteoarthritis both at home and abroad. The recommendations established using methods of evidence-based medicine has experienced strict research on controlling bias and promoting reproduction rate. As a result, the previous evidence was reevaluated, and a lot of changes were provoked in the diagnosis and treatment concept of osteoarthritis. However, several methods not recommended by foreign guidelines are still in use in the current clinical practice in China. On the one hand, Chinese experts have not reached extensive consensus on whether it is necessary to make changes according to foreign guidelines. On the other hand, almost all the current relevant guidelines are on osteoarthritis, but the lesions around knee joints which, as a whole, bear the largest weight in human body, cannot be ignored. For this purpose, Chinese Association for the Study of Pain (CASP) organized some leading experts to formulate this Chinese Pain Specialist Consensus on the diagnosis and treatment of degenerative knee osteoarthritis (DKOA) in combination with the guidelines in foreign countries and the expert experience of clinical practice in China. The consensus, which includes the definition, pathophysiology, epidemiology, clinical manifestation, diagnostic criteria, and treatments of DKOA, is intended to be used by first-line doctors, including pain physicians to manage patients with DKOA.

Anti-nociceptive effect of dexmedetomidine in a rat model of monoarthritis via suppression of the TLR4/NF-κB p65 pathway.

As a therapeutic target for neuropathic pain, the anti-nociceptive effects of α 2-adrenoceptors (α2AR) have attracted attention. Dexmedetomidine (DEX), a potent and highly selective α2AR agonist, has exhibited significant analgesic effects in neuropathic pain, but the underlying mechanism has remained elusive. The present study investigated the effect of DEX on Toll-like receptor (TLR)4 and nuclear factor (NF)-κB p65 expression, as well as the production of pro-inflammatory cytokines. The rat monoarthritis (MA) model was induced by intra-articular injection of complete Freund's adjuvant (CFA) at the ankle joint. After induction of MA, the rats were intrathecally treated with normal saline or DEX (2.5 µg) for 3 consecutive days. The concentration of interleukin-1ß and -6 as well as tumor necrosis factor-α was examined by ELISA. The expression levels of TLR4 and NF-κB p65 were determined by western blot analysis and immunohistochemistry. The results indicated that the pro-inflammatory cytokines TLR4 and NF-κB p65 were significantly upregulated in MA rats. DEX treatment markedly reduced mechanical and thermal hyperalgesia, suppressed MA-induced elevation of the pro-inflammatory cytokines and inhibited the TLR4/NF-κB p65 pathway, while these effects were blocked by pre-treatment with the selective α2AR antagonist BRL44408 (15 µg) at 30 min prior to CFA injection. These results suggested that DEX has an anti-nociceptive effect via suppressing the TLR4/NF-κB p65 pathway.

CX3CR1-Mediated Akt1 Activation Contributes to the Paclitaxel-Induced Painful Peripheral Neuropathy in Rats.

Painful peripheral neuropathy is a serious dose-limiting side effect of paclitaxel therapy, which unfortunately often happens during the optimal clinical management of chemotherapy in cancer patients. Currently the underlying mechanisms of the painful peripheral neuropathy remain largely unknown. Here, we found that paclitaxel treatment (3 × 8 mg/kg, cumulative dose 24 mg/kg) upregulated the expression of CX3CR1 and phosphorylated Akt1 in DRG and spinal dorsal horn. Blocking of Akt1 pathway activation with different inhibitor (MK-2206 or LY294002) significantly attenuated mechanical allodynia and thermal hyperalgesia induced by paclitaxel. Furthermore, inhibition of CX3CR1 by using neutralizing antibody not only prevented Akt1 activation in DRG and spinal dorsal horn but also alleviated pain-related behavior induced by paclitaxel treatment. This study suggested that CX3CR1/Akt1 signaling pathway may be a potential target for prevention and reversion of the painful peripheral neuropathy induced by paclitaxel.

Validation of a Simplified Chinese Version of the Pain Catastrophizing Scale and an Exploration of the Factors Predicting Catastrophizing in Pain Clinic Patients.

BACKGROUND: Chronic pain is very common worldwide and can lead to disability, depression and absence from work. Catastrophizing has been proven to affect individuals' belief systems and coping strategies, and it is an essential risk factor for chronic pain. The pain catastrophizing scale (PCS) has been developed for the assessment of catastrophizing. However, a Chinese version of this scale is not available, and physicians are therefore unable to determine which patients are prone to catastrophizing. Additionally, the risk factors for catastrophizing are unknown. OBJECTIVE: We aimed to cross-culturally adapt and validate the PCS for simplified Chinese (SC-PCS) and explore the risk factors for catastrophizing in patients from a pain clinic. STUDY DESIGN: We utilized a prospective, nonrandomized, cross-sectional, descriptive survey design. A second analysis of test-retest reliability was performed in a longitudinal, observational study. SETTING: A convenience sample was recruited from a pain clinic in a tertiary hospital. METHODS: This study was performed in 3 stages. In the first stage, the PCS was translated and culturally adapted to create a Chinese version; in the second stage, the measurement properties of the SC-PCS were tested, including the content validity, construct validity and reliability; and in the third stage, factors affecting catastrophizing in a pain clinic setting were explored. The adaptation was performed using a forward-backward method, and content validity was analyzed by examining the response trend (Z-skewness and item-total correlation). Construct validity was analyzed by assessing structural validity (confirmatory factor analysis [CFA] and exploratory factor analysis [EFA]) and a priori hypothesis testing. Reliability was analyzed by internal consistency (Cronbach's alpha) and test-retest reliability (intraclass correlation coefficient [ICC]). Risk factors for catastrophizing were analyzed by multivariate linear regression. RESULTS: A total of 153 patients were included, with a response rate of 96%; no items were excluded from the SC-PCS. Both CFA and EFA confirmed a 3-factor structure, and 9/10 of the hypotheses were verified for construct validity. Excellent reliability was acquired with a Cronbach's alpha of 0.91, and an ICC of 0.94 was determined. Risk factors for catastrophizing included college education (beta = 0.47), pain duration (beta = 0.40), female (beta = 0.31), freelancer status (beta = 0.31), and retired status (beta = 0.19). LIMITATIONS: The recruited patients experienced severe pain or long-duration pain in a pain clinic setting. This may limit the applicability of the SC-PCS to patients with low or moderate pain levels. CONCLUSION: The PCS has been linguistically translated into simplified Chinese and culturally adapted for a Chinese population with remarkable clinical acceptance, good construct validity, and excellent internal consistency and test-retest reliability. Education, pain duration, marital status, gender, income, and use of pain medications are important factors affecting catastrophizing.

Effect of non-steroidal anti-inflammatory drugs on the increasing the incidence of colonic anastomosis in rats.

BACKGROUND: Anastomotic leakage is one of serious complications of colorectal surgery. Research is inconsistent about whether non-steroidal anti-inflammatory drugs influence the healing of colorectal anastomoses and increase the incidence of anastomotic leakage. OBJECTIVE: To study the influence of NSAIDs on the healing of rat colonic anastomoses. DESIGN: This was an animal randomized-control trial. This study was approved by the ethical committee of Yangpu Hospital, Tongji University. INTERVENTION: 90 healthy Sprague-Dawley rats were randomly divided into 6 groups of 15 rats/group. Trail was performed in C (cotrol group) with no drugs, group M with morphine for analgesia, group F with flurbiprofen axeil, group L with lornoxicam, and group P with parecoxib sodium. MAIN OUTCOME MEASURES: The main outcomes measures were serological indexes including vascular endothelial growth factor, prostaglandin E2, hydroxyproline, and C reactive protein; histological specimens from the anastomotic stoma tissue including the collagen proportion, and hydroxyproline, cycloxygenase-2, and vascular endothelial growth factor content; physical indicators, including stoma fracture pressure, fracture strength and anastomotic leakage. RESULTS: No significant difference was observed among the indices of each group (P > 0.05). A significant difference occurred after operation (P < 0.05), with the data for groups K and M being dramatically higher than those for group F. LIMITATION: The study was nonblinded. CONCLUSION: The postoperative usages of non-steroidal anti-inflammatory drugs can decrease the strength of anastomotic tissue, and increase the incidence of anastomotic leakage.

p38 and interleukin-1 beta pathway via toll-like receptor 4 contributed to the skin and muscle incision and retraction-induced allodynia.

BACKGROUND: Persistent postsurgical pain, as an important clinical problem, seriously affects the quality of life in patients. However, the mechanism underlying persistent postsurgical pain remains largely unclear. The present study aims to elucidate the involvement of toll-like receptor 4 (TLR4) and its interaction with p38 and interleukin [IL]-1ß signaling in dorsal root ganglion (DRG) in the persistent postsurgical pain. METHODS: Skin and muscle incision and retraction (SMIR) surgery-induced paw withdrawal threshold (PWT) change was determined by applying mechanical stimuli to the plantar surface of the hind paw using von Frey hairs. The PE-10 catheter intrathecal placement was used to deliver LPS-RS, interleukin-1 receptor antagonist, or SB203580. Western blot analysis was performed to measure the expression of the TLR4, mitogen-activated protein kinases family, and IL-1ß in ipsilateral L3 and L4 DRG. Immunofluorescence staining was performed to further investigate the cell type of TLR4 expression. All data were expressed as means ± standard error of the mean and analyzed using SPSS 13.0. RESULTS: The results showed that the SMIR surgery, a rat model of persistent postoperative pain, decreased the ipsilateral 50% PWT, and the decrease lasted for at least 20 d. The expression of TLR4 and phosphorylation of p38 were upregulated in ipsilateral L3 and L4 DRG neurons after SMIR surgery. Pretreatment with LPS-RS, an established TLR4 antagonist, prevented p38 activation and attenuated mechanical allodynia induced by SMIR surgery. In addition, the expression of IL-1ß was significantly increased after SMIR surgery. Blocking IL-1ß by interleukin-1 receptor antagonist significantly improved the decreased PWT evoked by SMIR. Moreover, inhibition of TLR4 or p38 pathway prevented the IL-1ß upregulation and mechanical allodynia induced by SMIR. CONCLUSIONS: These findings suggest that the activation of p38 and IL-1ß signaling pathway via TLR4 mediate mechanical allodynia after SMIR surgery.

Involvement of spinal microglia and interleukin-18 in the anti-nociceptive effect of dexmedetomidine in rats subjected to CCI.

Dexmedetomidine, a selective alpha 2-adrenoceptor (α2AR) agonist, has provided significant analgesia in neuropathic pain. However, its underlying molecular mechanism has not been fully elucidated. In the present study, we found that intrathecal administration of dexmedetomidine alleviated mechanical allodynia induced by chronic constriction injury (CCI), and pretreatment with BRL44408 significantly reversed the dexmedetomidine-induced anti-nociceptive effect. Western blotting revealed that dexmedetomidine reduced the activation of microglia and the upregulation of interleukin-18 (IL-18) protein expression in the ipsilateral lumbar spinal dorsal horn, while BRL44408 pretreatment significantly blocked these effects of dexmedetomidine. Immunocytochemistry/immunohistochemistry indicated that the α2A-adrenoceptor was localised to microglia in primary culture, and IL-18 predominantly colocalised with the microglial marker Iba-1 in the dorsal horn of the spinal cord. These results suggest that the IL-18 signalling pathway in microglia may be involved in the anti-nociceptive effect of dexmedetomidine in rats subjected to CCI.

Dexmedetomidine inhibits the secretion of high mobility group box 1 from lipopolysaccharide-activated macrophages in vitro.

BACKGROUND: High mobility group box 1 (HMGB1) is a critical proinflammatory factor that is closely related to mortality in sepsis patients. Dexmedetomidine has been proven to reduce the mortality rate from endotoxin shock and attenuate endotoxin-induced acute lung injury. These effects result from reduced secretion of many proinflammatory mediators, although it is not clear whether dexmedetomidine affects the secretion of HMGB1. In this study, we explored the effect of dexmedetomidine on the expression and secretion of HMGB1 from lipopolysaccharide (LPS)-activated macrophages. METHODS: We incubated RAW264.7 cells with LPS in the presence or absence of various concentrations of dexmedetomidine. We used an enzyme-linked immunosorbent assay to detect the secretion levels of HMGB1 in the culture supernatant. We employed real-time polymerase chain reaction to assess the expression of HMGB1 mRNA, and used a nuclear/cytoplasm extraction kit to extract the nuclear and cytoplasmic proteins. We employed Western blotting to observe changes in the translocation of HMGB1 from the nucleus to the cytoplasm. In addition, we used a nuclear factor (NF)-κB p50/p65 transcription factor assay kit to analyze NF-κB activity in the nuclear extract. RESULTS: Dexmedetomidine inhibited the translocation of HMGB1 from the nucleus to the cytoplasm and its extracellular secretion in LPS-activated macrophages while suppressing the expression of HMGB1 mRNA. Dexmedetomidine inhibited the translocation of NF-κB from the cytoplasm to the nucleus in LPS-activated macrophages in a dose-dependent manner. Moreover, these effects were significantly reversed by the α2-adrenergic receptor antagonist yohimbine. CONCLUSIONS: Our study demonstrates that dexmedetomidine inhibits the translocation of HMGB1 from the nucleus to the cytoplasm and the expression of HMGB1 mRNA at clinically relevant dosages. The mechanism responsible for these effects may be through the NF-κB signaling pathway and the α2-adrenergic receptors.