Low-Intensity Focused Ultrasound Alleviates Chronic Neuropathic Pain-Induced Allodynia by Inhibiting Neuroplasticity in the Anterior Cingulate Cortex.

Low-intensity focused ultrasound (LIFU) is a potential noninvasive method to alleviate allodynia by modulating the central nervous system. However, the underlying analgesic mechanisms remain unexplored. Here, we assessed how LIFU at the anterior cingulate cortex (ACC) affects behavior response and central plasticity resulting from chronic constrictive injury (CCI). The safety of LIFU stimulation was assessed by hematoxylin and eosin (H&E) and Fluoro-Jade C (FJC) staining. A 21-day ultrasound exposure therapy was conducted from day 91 after CCI surgery in mice. We assessed the 50% mechanical withdrawal threshold (MWT50) using Von Frey filaments (VFFs). The expression levels of microtubule-associated protein 2 (MAP2), growth-associated protein 43 (GAP43), and tau were determined via western blotting (WB) and immunofluorescence (IF) staining to evaluate the central plasticity in ACC. The regions of ACC were activated effectively and safely by LIFU stimulation, which significantly increased the number of c-fos-positive cells (P < 0.05) with no bleeding, coagulative necrosis, and neuronal loss. Under chronic neuropathic pain- (CNP-) induced allodynia, MWT50 decreased significantly (P < 0.05), and overexpression of MAP2, GAP43, and tau was also observed. After 3 weeks of treatment, significant increases in MWT50 were found in the CCI+LIFU group compared with the CCI group (P < 0.05). WB and IF staining both demonstrated a significant reduction in the expression levels of MAP2, GAP43, and tau (P < 0.05). LIFU treatment on ACC can effectively attenuate CNP-evoked mechanical sensitivity to pain and reverse aberrant central plasticity.

The top 50 most cited articles in carpal tunnel syndrome research: A bibliometrics study.

BACKGROUND: Citation analysis was applied to identify the influential studies in the specific field. More and more literature related to carpal tunnel syndrome (CTS) have been published in recent years. To our knowledge, no one has performed a citation analysis of CTS. Thus, our study identified the top 50 influential articles pertaining to CTS and conduct an analysis of their characteristics. METHODS: The Web of Science database was used to identify all the articles from 1900 to 2020. We obtained the top 50 articles ranked by citation times, and articles were included and excluded based on the relevance to CTS. Also, we collected the information about journal name, level of evidence, source country and institution, and research type for further analysis. RESULTS: The top 50 articles were published between 1959 and 2012. The number of citations ranged from 151 to 1083. The citation density was between 3.23 and 40.27 per year. Muscle Nerve published most articles in CTS research, followed by Journal of Bone and Joint Surgery American Volume. The USA was the leading country, and all the top 5 institutions were from the USA. Katz JN with the highest h-index published most articles. Level III was the most common evidence level. CONCLUSIONS: We identified the top 50 cited articles related to CTS. These influential articles might provide researchers with a comprehensive list of the major contribution related to CTS research.

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.

LIFU Alleviates Neuropathic Pain by Improving the KCC2 Expression and Inhibiting the CaMKIV-KCC2 Pathway in the L4-L5 Section of the Spinal Cord.

Effective treatment remains lacking for neuropathic pain (NP), a type of intractable pain. Low-intensity focused ultrasound (LIFU), a noninvasive, cutting-edge neuromodulation technique, can effectively enhance inhibition of the central nervous system (CNS) and reduce neuronal excitability. We investigated the effect of LIFU on NP and on the expression of potassium chloride cotransporter 2 (KCC2) in the spinal cords of rats with peripheral nerve injury (PNI) in the lumbar 4-lumbar 5 (L4-L5) section. In this study, rats received PNI surgery on their right lower legs followed by LIFU stimulation of the L4-L5 section of the spinal cord for 4 weeks, starting 3 days after surgery. We used the 50% paw withdraw threshold (PWT50) to evaluate mechanical allodynia. Western blotting (WB) and immunofluorescence (IF) were used to calculate the expression of phosphorylated extracellular signal-regulated kinase 1/2 (p-ERK1/2), calcium/calmodulin-dependent protein kinase type IV (CaMKIV), phosphorylated cyclic adenosine monophosphate response element-binding protein (p-CREB), and KCC2 in the L4-L5 portion of the spinal cord after the last behavioral tests. We found that PWT50 decreased (P < 0.05) 3 days post-PNI surgery in the LIFU- and LIFU+ groups and increased (P < 0.05) after 4 weeks of LIFU stimulation. The expression of p-CREB and CaMKIV decreased (P < 0.05) and that of KCC2 increased (P < 0.05) after 4 weeks of LIFU stimulation, but that of p-ERK1/2 (P > 0.05) was unaffected. Our study showed that LIFU could effectively alleviate NP behavior in rats with PNI by increasing the expression of KCC2 on spinal dorsal corner neurons. A possible explanation is that LIFU could inhibit the activation of the CaMKIV-KCC2 pathway.

Gnaq Protects PC12 Cells from Oxidative Damage by Activation of Nrf2 and Inhibition of NF-kB.

Reactive oxygen species (ROS) are continuously produced as byproducts of aerobic metabolism. Oxidative stress (OS) plays an important role in the occurrence of several neurodegenerative diseases as well as aging because of the accumulation of ROS. Gnaq is a member of G protein α subunits. It has been reported that the expression level of Gnaq in the mouse forebrain cortex was significantly decreased with age in our previous study; therefore, we supposed that Gnaq contributes to attenuate the OS. In this study, we generated a Gnaq-overexpression cell using gene recombinant technique and lentivirus transfection technique in a neuron-like PC12 cell, and investigated whether Gnaq had antioxidant effects in PC12 cells treated with H2O2. The viability of cells, concentration of ROS, Nrf2 nuclear translocation, expression of antioxidant enzymes, activation of NF-κB and apoptosis were compared between Gnaq-PC12 cells and Vector-PC12 cells. Results showed that, compared with Vector-PC12 cells, the antioxidative ability of Gnaq-PC12 cells was significantly improved, while the ROS level in Gnaq-PC12 cells was significantly decreased. Nrf2 nuclear translocation was up-regulated and NF-κB nuclear translocation was down-regulated in Gnaq-PC12 cells after H2O2 treatment. The results suggest that Gnaq plays a crucial role in neuroprotection in PC12 cells. A possible mechanism for this would be that the overexpressed Gnaq enhances the antioxidative effect mediated by Nrf2 signal pathway and inhibits the cellular damaging effect through NF-κB signal pathway.