Effect of nerve growth factor on elderly degenerative knee osteoarthritis pain / 中国骨伤

OBJECTIVE@#To explore effect of nerve growth factor (NGF) antibody on knee osteoarthritis (KOA) pain model was evaluated by in vitro model.@*METHODS@#Thirty male SPF rats aged 28-week-old were divided into blank group (10 rats with anesthesia only). The other 20 rats were with monoiodoacetate (MIA) on the right knee joint to establish pain model of OA, and were randomly divided into control group (injected intraperitoneal injection of normal saline) and treatment group (injected anti-NGF) intraperitoneal after successful modeling, and 10 rats in each group. All rats were received retrograde injection of fluorogold (FG) into the right knee joint. Gait was assessed using catwalk gait analysis system before treatment, 1 and 2 weeks after treatment. Three weeks after treatment, right dorsal root ganglia (DRG) were excised on L4-L6 level, immunostained for calcitonin gene-related peptide (CGRP), and the number of DRGS was counted.@*RESULTS@#In terms of gait analysis using cat track system, duty cycle, swing speed and print area ratio in control and treatment group were significantly reduced compared with blank group (P<0.05). Compared with control group, duty cycle and swing speed of treatment group were significantly improved (P<0.05), and there was no significant difference in print area ratio between treatment group and blank group (P>0.05). The number of FG-labeled DRG neurons in control group was significantly higher than that in treatment group and blank group (P<0.05). The expression of CGRP in control group was up-regulated, and differences were statistically significant compared with treatment group (P<0.05).@*CONCLUSION@#Intraperitoneal injection of anti-NGF antibody inhibited gait injury and upregulation of CGRP in DRG neurons. The results suggest that anti-nerve growth factor therapy may be of value in treating knee pain. NGF may be an important target for the treatment of knee OA pain.

Deciphering the dynamic characteristics of non-neuronal cells in dorsal root ganglion of rat at different developmental stage based on single cell transcriptome data / 生物工程学报

Dorsal root ganglia (DRG) is an essential part of the peripheral nervous system and the hub of the peripheral sensory afferent. The dynamic changes of neuronal cells and their gene expression during the development of dorsal root ganglion have been studied through single-cell RNAseq analysis, while the dynamic changes of non-neuronal cells have not been systematically studied. Using single cell RNA sequencing technology, we conducted a research on the non-neuronal cells in the dorsal root ganglia of rats at different developmental stage. In this study, primary cell suspension was obtained from using the dorsal root ganglions (DRGs, L4-L5) of ten 7-day-old rats and three 3-month-old rats. The 10×Genomics platform was used for single cell dissociation and RNA sequencing. Twenty cell subsets were acquired through cluster dimension reduction analysis, and the marker genes of different types of cells in DRG were identified according to previous researches about DRG single cell transcriptome sequencing. In order to find out the non-neuronal cell subsets with significant differences at different development stage, the cells were classified into different cell types according to markers collected from previous researches. We performed pseudotime analysis of 4 types Schwann cells. It was found that subtype Ⅱ Schwann cells emerged firstly, and then were subtype Ⅲ Schwann cells and subtype Ⅳ Schwann cells, while subtype Ⅰ Schwann cells existed during the whole development procedure. Pseudotime analysis indicated the essential genes influencing cell fate of different subtypes of Schwann cell in DRG, such as Ntrk2 and Pmp2, which affected cell fate of Schwann cells during the development period. GO analysis of differential expressed genes showed that the up-regulated genes, such as Cst3 and Spp1, were closely related to biological process of tissue homeostasis and multi-multicellular organism process. The down regulated key genes, such as Col3a1 and Col4a1, had close relationship with the progress of extracellular structure organization and negative regulation of cell adhesion. This suggested that the expression of genes enhancing cell homestasis increased, while the expression of related genes regulating ECM-receptor interaction pathway decreased during the development. The discovery provided valuable information and brand-new perspectives for the study on the physical and developmental mechanism of Schwann cell as well as the non-neuronal cell changes in DRG at different developmental stage. The differential gene expression results provided crucial references for the mechanism of somatosensory maturation during development.

The Antinociceptive Effect of Sympathetic Block is Mediated by Transforming Growth Factor β in a Mouse Model of Radiculopathy / 神经科学通报·英文版

Although sympathetic blockade is clinically used to treat pain, the underlying mechanisms remain unclear. We developed a localized microsympathectomy (mSYMPX), by cutting the grey rami entering the spinal nerves near the rodent lumbar dorsal root ganglia (DRG). In a chemotherapy-induced peripheral neuropathy model, mSYMPX attenuated pain behaviors via DRG macrophages and the anti-inflammatory actions of transforming growth factor-β (TGF-β) and its receptor TGF-βR1. Here, we examined the role of TGF-β in sympathetic-mediated radiculopathy produced by local inflammation of the DRG (LID). Mice showed mechanical hypersensitivity and transcriptional and protein upregulation of TGF-β1 and TGF-βR1 three days after LID. Microsympathectomy prevented mechanical hypersensitivity and further upregulated Tgfb1 and Tgfbr1. Intrathecal delivery of TGF-β1 rapidly relieved the LID-induced mechanical hypersensitivity, and TGF-βR1 antagonists rapidly unmasked the mechanical hypersensitivity after LID+mSYMPX. In situ hybridization showed that Tgfb1 was largely expressed in DRG macrophages, and Tgfbr1 in neurons. We suggest that TGF-β signaling is a general underlying mechanism of local sympathetic blockade.

Microglial Depletion does not Affect the Laterality of Mechanical Allodynia in Mice / 神经科学通报·英文版

Mechanical allodynia (MA), including punctate and dynamic forms, is a common and debilitating symptom suffered by millions of chronic pain patients. Some peripheral injuries result in the development of bilateral MA, while most injuries usually led to unilateral MA. To date, the control of such laterality remains poorly understood. Here, to study the role of microglia in the control of MA laterality, we used genetic strategies to deplete microglia and tested both dynamic and punctate forms of MA in mice. Surprisingly, the depletion of central microglia did not prevent the induction of bilateral dynamic and punctate MA. Moreover, in dorsal root ganglion-dorsal root-sagittal spinal cord slice preparations we recorded the low-threshold Aβ-fiber stimulation-evoked inputs and outputs of superficial dorsal horn neurons. Consistent with behavioral results, microglial depletion did not prevent the opening of bilateral gates for Aβ pathways in the superficial dorsal horn. This study challenges the role of microglia in the control of MA laterality in mice. Future studies are needed to further understand whether the role of microglia in the control of MA laterality is etiology-or species-specific.

Mechanosensitive Ion Channel TMEM63A Gangs Up with Local Macrophages to Modulate Chronic Post-amputation Pain / 神经科学通报·英文版

Post-amputation pain causes great suffering to amputees, but still no effective drugs are available due to its elusive mechanisms. Our previous clinical studies found that surgical removal or radiofrequency treatment of the neuroma at the axotomized nerve stump effectively relieves the phantom pain afflicting patients after amputation. This indicated an essential role of the residual nerve stump in the formation of chronic post-amputation pain (CPAP). However, the molecular mechanism by which the residual nerve stump or neuroma is involved and regulates CPAP is still a mystery. In this study, we found that nociceptors expressed the mechanosensitive ion channel TMEM63A and macrophages infiltrated into the dorsal root ganglion (DRG) neurons worked synergistically to promote CPAP. Histology and qRT-PCR showed that TMEM63A was mainly expressed in mechanical pain-producing non-peptidergic nociceptors in the DRG, and the expression of TMEM63A increased significantly both in the neuroma from amputated patients and the DRG in a mouse model of tibial nerve transfer (TNT). Behavioral tests showed that the mechanical, heat, and cold sensitivity were not affected in the Tmem63a-/- mice in the naïve state, suggesting the basal pain was not affected. In the inflammatory and post-amputation state, the mechanical allodynia but not the heat hyperalgesia or cold allodynia was significantly decreased in Tmem63a-/- mice. Further study showed that there was severe neuronal injury and macrophage infiltration in the DRG, tibial nerve, residual stump, and the neuroma-like structure of the TNT mouse model, Consistent with this, expression of the pro-inflammatory cytokines TNF-α, IL-6, and IL-1β all increased dramatically in the DRG. Interestingly, the deletion of Tmem63a significantly reduced the macrophage infiltration in the DRG but not in the tibial nerve stump. Furthermore, the ablation of macrophages significantly reduced both the expression of Tmem63a and the mechanical allodynia in the TNT mouse model, indicating an interaction between nociceptors and macrophages, and that these two factors gang up together to regulate the formation of CPAP. This provides a new insight into the mechanisms underlying CPAP and potential drug targets its treatment.

Baimai Ointment relieves chronic pain induced by chronic compression of dorsal root ganglion in rats by regulating neuroactive ligand-receptor interaction and HIF-1 signaling pathway / 中国中药杂志

The Baimai Ointment with the effect of relaxing sinew and activating collaterals demonstrates a definite effect on Baimai disease with pain, spasm, stiffness and other symptoms, while the pharmacodynamic characteristics and mechanism of this agent remain unclear. In this study, a rat model of chronic compression of L4 dorsal root ganglion(CCD) was established by lumbar disc herniation, and the efficacy and mechanism of Baimai Ointment in the treatment of CCD were preliminarily explored by behavioral tests, side effect evaluation, network analysis, antagonist and molecular biology verification. The pharmacodynamic experiment indicated that Baimai Ointment significantly improved the pain thresholds(mechanical pain, thermal pain, and cold pain) and gait behavior of CCD model rats without causing tolerance or obvious toxic and side effects. Baimai Ointment inhibited the second-phase nociceptive response of mice in the formalin test, increased the hot plate threshold of normal mice, and down-regulated the expression of inflammatory cytokines in the spinal cord. Network analysis showed that Baimai Ointment had synergistic effect in the treatment of CCD and was related to descending inhibition/facilitation system and neuroinflammation. Furthermore, behavioral tests, Western blot, and immunofluorescence assay revealed that the pain-relieving effect of Baimai Ointment on CCD may be related to the regulation of the interaction between neuroactive ligand and receptors(neuroligands) such as CHRNA7, ADRA2A, and ADRB2, and the down-regulation of the expression of NOS2/pERK/PI3K, the core regulatory element of HIF-1 signaling pathway in spinal microglia. The findings preliminarily reveal the mechanism of relaxing sinew and activating collaterals of Baimai Ointment in the treatment of Baimai disease, providing a reference for the rational drug use and further research of this agent.

An experimental study of tangzhouling on morphological changes of nissl bodies in the dorsal root ganglion of DM rats / Un estudio experimental de tangzhouling sobre los cambios morfológicos de los cuerpos de nissl en el ganglio de la raíz dorsal de ratas DM

SUMMARY: This study aims to investigate the effect of Tangzhouling on the morphological changes of Nissl bodies in the dorsal root ganglion of DM Rats. In this study, 69 rats were randomly divided into a control group (n = 10) and a model group (n = 59). The rats in the model group were randomly divided into a diabetic group (n = 11), a vitamin C group (n = 12), a low dose Tangzhouling group (n = 12), a medium dose Tangzhouling group (n = 12) and a high dose Tangzhouling group (n = 12). The dose of Tangzhouling in the low dose group was 5 times that of the adult dose, being 0.44g/kg/d. The dose of Tangzhouling in the medium dose group was 10 times that of the adult dose, being 0.88g/kg/d. The dose of Tangzhouling in the high dose group was 20 times that of the adult dose, being 1.75g/kg/d. All doses above are crude drug dosages. Rats in the vitamin C group were given 10 times the dose of an adult, being, 0.05 g/ kg/d. The diabetic group and the control group were given the same amount of distilled water. Drug delivery time is 16 weeks. The dorsal root ganglion was placed in a freezing tube at the end of the experiment. The morphological changes of Nissl bodies in the dorsal root ganglion were detected by HE and Nissl staining. The study results showed that vitamin C had no significant effect on the quantity, size and nucleolus. Tangzhouling can improvee the morphology, quantity and nucleolus of Nissl bodies to a certain extent, and the high dose is better than the lower dose. Tangzhouling capsules can improve the nerve function of DM rats through Nissl bodies.

RESUMEN: Este estudio tuvo como objetivo investigar el efecto de Tangzhouling en los cambios morfológicos de los cuerpos de Nissl en el ganglio de la raíz dorsal de las ratas DM. En este estudio, 69 ratas se dividieron aleatoriamente en un grupo control (n = 10) y un grupo modelo (n = 59). Las ratas del grupo modelo se dividieron aleatoriamente en un grupo diabéticos (n = 11), un grupo vitamina C (n = 12), un grupo de dosis baja de Tangzhouling (n = 12), un grupo de dosis media de Tangzhouling (n = 12) y un grupo de dosis alta de Tangzhouling (n = 12). La dosis de Tangzhouling en el grupo de dosis baja fue 5 veces mayor que la dosis del adulto, siendo 0,44 g/kg/d. La dosis de Tangzhouling en el grupo de dosis media fue 10 veces mayor que la dosis del adulto, siendo 0,88 g/kg/d. La dosis de Tangzhouling en el grupo de dosis alta fue 20 veces mayor que la dosis del adulto, siendo 1,75 g/kg/d. Todas las dosis anteriores son dosis de fármaco crudo. Se les administró 10 veces la dosis de un adulto a las ratas del grupo vitamina C, siendo 0,05 g/kg/d. El grupo de diabéticos y el grupo de control recibieron la misma cantidad de agua destilada. El tiempo de entrega del fármaco fue de 16 semanas. El ganglio de la raíz dorsal se colocó en un tubo de congelación al final del experimento. Los cambios morfológicos de los cuerpos de Nissl en el ganglio de la raíz dorsal se detectaron mediante tinción de HE y Nissl. Los resultados del estudio mostraron que la vitamina C no tuvo un efecto significativo sobre la cantidad, el tamaño y el nucléolo. Tangzhouling puede mejorar la morfología, la cantidad y el nucléolo de los cuerpos de Nissl hasta cierto punto, y es mejor la dosis alta que la dosis baja. Las cápsulas de Tangzhouling pueden mejorar la función nerviosa de las ratas DM a través de los cuerpos de Nissl.

Genistein attenuates LPS-induced inflammatory injury of rat dorsal root ganglion neuron via down-regulating HDAC6 / 中南大学学报(医学版)

OBJECTIVES@#Neuropathic pain (NP) is a chronic pain caused by somatosensory neuropathy or disease, and genistein (Gen) might be a potential drug for the treatment of NP. Therefore, this study aims to investigate the effect of Gen on lipopolysaccharide (LPS)-induced inflammatory injury of dorsal root ganglion neuron (DRGn) in rats and the possible molecular mechanism.@*METHODS@#The DRGn of 1-day-old juvenile rats were taken for isolation and culture. The DRGn in logarithmic growth phase were divided into a control group, a LPS group, a tubastatin hydrochloride (TSA)+LPS group, a Gen1+LPS group, a Gen2+LPS group, a Gen2+LPS+TSA group, a Gen2+pcDNA-histone deacetylase 6 (HDAC6)+LPS group, and a Gen2+pcDNA3.1+LPS group. The LPS group was treated with 1 μg/mL LPS for 24 h; the TSA+LPS group, the Gen1+LPS group, the Gen2+LPS group were treated with 5 μmol/L TSA, 5 μmol/L Gen, 10 μmol/L Gen respectively for 0.5 h, and then added 1 μg/mL LPS for 24 h; the Gen2+TSA+LPS group was treated with 10 μmol/L Gen and 5 μmol/L TSA for 0.5 h and then added 1 μg/mL LPS for 24 h; the Gen2+pcDNA-HDAC6+LPS group and the Gen2+pcDNA3.1+LPS group received 100 nmol/L pcDNA-HDAC6 and pcDNA3.1 plasmids respectively, and 24 h after transfection, 10 μmol/L Gen was pretreated for 0.5 h, and then added 1 μg/mL LPS for 24 h. Real-time RT-PCR was used to detect the HDAC6 mRNA expression in DRGn; CCK-8 method was used to detect cell viability of DRGn; flow cytometry was used to detect cell apoptosis of DRGn; ELISA was used to detect the levels of IL-1β, IL-6, and TNF-α in DRGn culture supernatant; Western blotting was used to detect the protein expression of HDAC6, Toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), and NF-κB p65 in DRGn.@*RESULTS@#Compared with the control group, the expression levels of HDAC6 mRNA and protein, the expression levels of TLR4 and MyD88 protein in DRGn of LPS group rats were significantly up-regulated, the ratio of p-NF-κB p65/NF-κB p65 was significantly increased, and the activity of DRGn was significantly decreased, the apoptosis rate was significantly increased, and the levels of IL-1β, IL-6 and TNF-α in the DRGn culture supernatant were significantly increased (all P<0.05). Compared with the LPS group, the expression levels of HDAC6 mRNA and protein, TLR4 and MyD88 protein expression levels in DRGn of the TSA+LPS group, the Gen1+LPS group, the Gen2+LPS group and the Gen2+TSA+LPS group were significantly down-regulated, the ratio of p-NF-κB p65/NF-κB p65 was significantly decreased, the activity of DRGn was significantly increased, the apoptosis rate was significantly decreased, and the levels of IL-1β, IL-6 and TNF-α in the DRGn culture supernatant were significantly decreased (all P<0.05), and the above changes were most obvious in the Gen2+TSA+LPS group. Compared with the Gen2+LPS group, the expression levels of HDAC6 mRNA and protein, TLR4 and MyD88 protein expression levels in DRGn of the Gen2+pcDNA-HDAC6+LPS group were significantly up-regulated, the ratio of p-NF-κB p65/NF-κB p65 was significantly increased, the activity of DRGn was significantly decreased, and the apoptosis rate was significantly increased, and the levels of IL-1β, IL-6 and TNF-α in the DRGn culture supernatant were significantly increased (all P<0.05).@*CONCLUSIONS@#Gen can alleviate LPS-induced DRGn inflammatory injury in rats, which might be related to down-regulating the expression of HDAC6 and further inhibiting the activation of TLR4/MyD88/NF-κB signaling pathway.

Referred Somatic Hyperalgesia Mediates Cardiac Regulation by the Activation of Sympathetic Nerves in a Rat Model of Myocardial Ischemia / 神经科学通报·英文版

Myocardial ischemia (MI) causes somatic referred pain and sympathetic hyperactivity, and the role of sensory inputs from referred areas in cardiac function and sympathetic hyperactivity remain unclear. Here, in a rat model, we showed that MI not only led to referred mechanical hypersensitivity on the forelimbs and upper back, but also elicited sympathetic sprouting in the skin of the referred area and C8-T6 dorsal root ganglia, and increased cardiac sympathetic tone, indicating sympathetic-sensory coupling. Moreover, intensifying referred hyperalgesic inputs with noxious mechanical, thermal, and electro-stimulation (ES) of the forearm augmented sympathetic hyperactivity and regulated cardiac function, whereas deafferentation of the left brachial plexus diminished sympathoexcitation. Intradermal injection of the α2 adrenoceptor (α2AR) antagonist yohimbine and agonist dexmedetomidine in the forearm attenuated the cardiac adjustment by ES. Overall, these findings suggest that sensory inputs from the referred pain area contribute to cardiac functional adjustment via peripheral α2AR-mediated sympathetic-sensory coupling.

Growth Differentiation Factor-15 Produces Analgesia by Inhibiting Tetrodotoxin-Resistant Nav1.8 Sodium Channel Activity in Rat Primary Sensory Neurons / 神经科学通报·英文版

Growth differentiation factor 15 (GDF-15) is a member of the transforming growth factor-β superfamily. It is widely distributed in the central and peripheral nervous systems. Whether and how GDF-15 modulates nociceptive signaling remains unclear. Behaviorally, we found that peripheral GDF-15 significantly elevated nociceptive response thresholds to mechanical and thermal stimuli in naïve and arthritic rats. Electrophysiologically, we demonstrated that GDF-15 decreased the excitability of small-diameter dorsal root ganglia (DRG) neurons. Furthermore, GDF-15 concentration-dependently suppressed tetrodotoxin-resistant sodium channel Nav1.8 currents, and shifted the steady-state inactivation curves of Nav1.8 in a hyperpolarizing direction. GDF-15 also reduced window currents and slowed down the recovery rate of Nav1.8 channels, suggesting that GDF-15 accelerated inactivation and slowed recovery of the channel. Immunohistochemistry results showed that activin receptor-like kinase-2 (ALK2) was widely expressed in DRG medium- and small-diameter neurons, and some of them were Nav1.8-positive. Blockade of ALK2 prevented the GDF-15-induced inhibition of Nav1.8 currents and nociceptive behaviors. Inhibition of PKA and ERK, but not PKC, blocked the inhibitory effect of GDF-15 on Nav1.8 currents. These results suggest a functional link between GDF-15 and Nav1.8 in DRG neurons via ALK2 receptors and PKA associated with MEK/ERK, which mediate the peripheral analgesia of GDF-15.

Early intervention of bone-nearby acupuncture combined with electroacupuncture on morphine tolerance in bone cancer pain rats and its effect on the expression of HDAC and MOR in dorsal root ganglia / 中国针灸

OBJECTIVE@#To observe the effect of early intervention of bone-nearby acupuncture (BNA) combined with electroacupuncture (EA) on the expression of histone deacetylase1(HDAC1), histone deacetylase 2 (HDAC2) andμ-opioid recepter (MOR) in dorsal root ganglia (DRG) of bone cancer pain-morphine tolerance (BCP-MT) rats, and to explore its possible mechanism.@*METHODS@#A total of 35 SD rats were randomized into a sham BCP group (=6), a BCP group (=7), a MT group (=7), a BNA+EA group (=8) and a shame BNA group (=7). Except of the sham BCP group, cancer cell inoculation operation at left tibia was given in the other 4 groups to establish the bone cancer pain model. In the MT group, the BNA+EA group and the shame BNA group, intraperitoneal injection of morphine hydrochloride was given to establish the morphine tolerance model. After the operation, bone-nearby acupuncture combined with electroacupuncture was applied at "Zusanli" (ST 36) and "Kunlun" (BL 60) in the BNA+EA group, with dilatational wave, 2 Hz/100 Hz in frequency, 0.5 to 1.5 mA in intensity. Intervention in the shame BNA group was applied at the same time and acupoints as those in the BNA+EA group, the needles were pierced the skin without any electrical stimulation. The needles were retained for 30 min, once a day for continuous 7 days in both BNA+EA and shame BNA groups. Before and 10, 11, 15, 22 days after the operation, the left paw withdrawal threshold (PWT) was measured in the 5 groups. The levels of HDAC1, HDAC2 and MOR in DRG were detected by Western blot.@*RESULTS@#Ten days after the cancer cell inoculation operation, the PWT of the BCP, MT, BNA+EA and sham BNA groups was decreased compared with the sham BCP group (0.05); the PWT of the BNA+EA group was increased compared with the MT and sham BNA group (<0.01). In the BCP group, the DRG levels of HDAC1 and HDCA2 were increased, while the level of MOR was decreased compared with the sham BCP group (<0.05, <0.01). In the MT group, the DRG level of HDAC1 was increased compared with the BCP group (<0.05). In the BNA+EA group, the DRG level of HDAC1 was decreased compared with the MT group and the sham BNA group (<0.01, <0.05), while the level of MOR was increased (<0.01).@*CONCLUSION@#Early intervention of bone-nearby acupuncture combined with electroacupuncture can relieve the morphine tolerance in bone cancer pain rats, it may relate to down-regulating the expression of HDAC1 and up-regulating the expression of MOR in the dorsal root ganglia.

Evaluation of the lumbar safety triangle through magnetic resonance imaging / Avaliação do triângulo de segurança lombar por meio da ressonância magnética / Evaluación del triángulo de seguridad lumbar por medio de la resonancia magnética

ABSTRACT Objective: To evaluate the lumbar triangular safety zone, its boundaries and its relationship with the dorsal root ganglion through Magnetic Resonance Imaging (MRI). Methods: The boundaries, shape and dimensions of 303 triangular safety zones were analyzed in Tesla 3.0 Magnetic Resonance Imaging (MRI) coronal sections from L2 to L5, including the dorsal root ganglion. Results: The sample consisted of 101 patients with a mean age of 32 years. The height of the triangular safety zone was formed by the lateral edge of the dura mater, the width by the upper plateau of the lower vertebra and the hypotenuse by the corresponding nerve root. The mean dimensions and the area varied according to the level studied. The dorsal root ganglion invaded the dimensions of the triangle in all the images studied. Conclusion: Based on the data and the analyses performed, we concluded that knowledge of the boundaries of the triangular safety zone through MRI increases the safety of minimally invasive procedures in the lumbar spine. Level of evidence I; Diagnostic studies - Investigation of a diagnostic test.

RESUMO Objetivo: Avaliar a zona triangular de segurança lombar, seus limites e sua relação com o gânglio da raiz dorsal por meio da ressonância magnética (RM). Métodos: Foram estudados os limites, o formato e as dimensões de 303 zonas triangulares de segurança no corte coronal de RM 3.0 Tesla de L2 a L5, incluindo o gânglio da raiz dorsal. Resultados: A amostra foi composta por 101 pacientes com média de idade de 32 anos. A altura da zona triangular de segurança era formada pela borda lateral da dura-máter; a largura, pelo platô superior da vértebra inferior; e a hipotenusa, pela raiz nervosa correspondente. A média das dimensões, assim como a área, variaram conforme o nível estudado. O gânglio da raiz dorsal invadiu as dimensões do triângulo em todas as imagens estudadas. Conclusão: Baseados nos dados e nas análises realizadas, concluímos que o conhecimento dos limites da zona triangular de segurança, por meio da imagem da RM, aumenta a segurança dos procedimentos minimamente invasivos na coluna lombar. Nível de evidência I; Estudos diagnósticos-Investigação de um exame para diagnóstico.

RESUMEN Objetivo: Evaluar la zona triangular de seguridad lumbar, sus límites y su relación con el ganglio de la raíz dorsal a través de la Resonancia Magnética (RM). Métodos: Se estudiaron los límites, el formato y las dimensiones de 303 zonas triangulares de seguridad en el corte coronal de RM 3.0 Tesla de L2 a L5, incluyendo el ganglio de la raíz dorsal. Resultados: La muestra fue compuesta por 101 pacientes, con promedio de edad de 32 años. La altura de la zona triangular de seguridad estaba formada por el borde lateral de la duramadre, el ancho por la meseta superior de la vértebra inferior y la hipotenusa por la raíz nerviosa correspondiente. El promedio de las dimensiones, así como el área, variaron según el nivel estudiado. El ganglio de la raíz dorsal invadió las dimensiones del triángulo en todas las imágenes estudiadas. Conclusión: Basándose en los datos y análisis realizados, concluimos que el conocimiento de los límites de la zona triangular de seguridad a través de la imagen de RM aumenta la seguridad de los procedimientos mínimamente invasivos en la columna lumbar. Nivel de evidencia I; Estudios diagnósticos - Investigación de un examen para diagnóstico.

Role of ZHX2 in regulating dorsal root ganglion μ-opioid receptor expression in mice with peripheral nerve injuryinduced pain hypersensitivity / 南方医科大学学报

OBJECTIVE@#To investigate the role of zinc-fingers and homeoboxes 2 (ZHX2) in regulating μ-opioid receptor expression in the dorsal root ganglion (DRG) in mice with peripheral nerve injury-induced pain hypersensitivity.@*METHODS@#Forty-eight male adult C57BL6J mice were randomized into 4 groups and subjected to chronic constriction injury (CCI) of the sciatic nerve or sham operation followed by microinjection of a specific small interfering RNA (siRNA) of ZHX2 or a negative control siRNA sequence (siNC) into the DRG. Seven days later, the mice were examined for changes in the hind paw withdrawal frequency (PWF), after which the DRG tissue was collected for detecting the expressions of μ-opioid receptor at the mRNA and protein levels using RT-qPCR and Western blotting. In another experiment, the DRG tissues were collected from 6 mice (21-day-old) for primary culture of the DRG neurons, which were transfected with ZHX2 siRNA or the siNC to observe the changes in the expressions of ZHX2 and μ-pioid receptor.@*RESULTS@#Microinjection of ZHX2 siRNA into the ipsilateral L3 and L4 DRGs significantly reversed CCI-induced μ-pioid receptor downregulation in the injured DRG and alleviated CCI-induced mechanical allodynia in the mice. In the cell experiment, ZHX2 knockdown obviously upregulated the mRNA and protein expressions of opioid receptor in the primary cultured DRG neurons.@*CONCLUSIONS@#ZHX2 knockdown in the DRG reverses CCI-induced down-regulation of μ opioid receptor to alleviate periphery nerve injury-induced pain hypersensitivity in mice.

Effect of cinobufagin on transient outward potassium current in dorsal root ganglion cells of rats with cancer-induced bone pain / 南方医科大学学报

OBJECTIVE@#To observe the effect of cinobufagin on transient outward potassium current () in rat dorsal root ganglion cells of cancer-induced bone pain (CIBP) and explore the possible analgesic mechanism of cinobufagin.@*METHODS@#Whole cell patch clamp technique was used to examine the effect of cionbufagin on in acutely isolated dorsal root ganglion (DRG) cells from normal SD rats and rats with bone cancer pain.@*RESULTS@#The DRG cells from rats with CIBP showed obviously decreased current density, an activation curve shift to the right, and an inactivation curve shift to the left. Cinobufagin treatment significantly increased the current density and reversed the changes in the activation and inactivation curves in the DRG cells.@*CONCLUSIONS@# current is decreased in DRG neurons from rats with CIBP. Cinobufagin can regulate the activation and inactivation of current in the DRG cells, which may be related to its analgesic mechanism.

Expression of KCNA2 in the dorsal root ganglia of rats with osteoarthritis pain induced by monoiodoacetate / 南方医科大学学报

OBJECTIVE@#To investigate the changes in the expression of voltage-gated potassium channel subunit KCNA2 in the dorsal root ganglion (DRG) neurons of rats with osteoarthritis (OA) pain induced by sodium monoiodoacetate and explore the mechanism.@*METHODS@#A total of 156 adult male Sprague-Dawley rats were randomly divided into blank control group, saline group and intra-articular monoiodoacetate injection-induced OA group. The paw withdrawal mechanical threshold (PWMT) was measured before and at 1, 2, 4, and 6 weeks after monoiodoacetate injection. At 4 weeks after the injection, the pathological changes in the knee joints were analyzed using HE staining and Safranin O-Fast Green staining, and the expression of activating transcription factor 3 (ATF-3) and inducible nitric oxide synthase (iNOS) in the DRG neurons were detected by immunofluorescence staining. The expression of mRNA in the DRG neurons was detected by RT-qPCR at 1, 2, 4 and 6 weeks after the injection. The expression of KCNA2 in the DRG was measured by Western blotting, and the methylation level of promoter region was measured by MSPCR at 4 weeks after the injection.@*RESULTS@#The PWMT of the rats in OA group was significantly decreased at 2, 4, and 6 weeks after the injection as compared with the baseline ( < 0.05 or < 0.001) as well as the control group ( < 0.05 or < 0.001). Four weeks after the intra-articular injection, fractures and defects on the surface of the articular cartilage, bone hyperplasia, and blurred tidal line were observed in the rats in OA group, but no obvious pathological changes were detected in the control or saline groups. Compared with those in the control group, the expressions of ATF-3 and iNOS were significantly increased ( < 0.01) at 4 weeks after injection; the expression of mRNA at 2, 4 and 6 weeks and the expression of KCNA2 protein at 4 weeks were all significantly decreased ( < 0.05 or < 0.01), and the methylation level of gene was significantly increased at 4 weeks after the injection in OA group ( < 0.01).@*CONCLUSIONS@#The expression of KCNA2 is decreased in the DRG neurons of rats with OA pain likely as a result of enhanced methylation of promoter region.

Research Advances in Mitogen-activated Protein Kinases in Central and Peripheral Sensitization of Diabetic Neuropathic Pain / 中国医学科学院学报

Mitogen-activated protein kinases(MAPKs)are Ser/Thr kinases consisting of extracellular regulated protein kinases(ERK)1/2,c-Jun N-terminal kinase 1/2/3,p38 isoforms(α,β,γ,and δ),and ERK5,which mediate a range of cellular activities including proliferation,differentiation,apoptosis,immunity,and inflammation. Pain sensitization is a remodeling mechanism of central and peripheral nociceptor. A growing number of evidences have indicated that MAPKs are extensively activated in the spinal dorsal cord and dorsal root ganglions in the animal models of diabetic neuropathic pain(DNP)and play an important role in the central and peripheral sensitization of DNP. In addition,some drugs can alleviate DNP by suppressing MAPKs activation of central and peripheral nervous system. This article summarizes the research progress of MAPKs in central and peripheral sensitization of DNP.

Neonatal Maternal Deprivation Followed by Adult Stress Enhances Adrenergic Signaling to Advance Visceral Hypersensitivity / 神经科学通报·英文版

The pathophysiology of visceral pain in patients with irritable bowel syndrome remains largely unknown. Our previous study showed that neonatal maternal deprivation (NMD) does not induce visceral hypersensitivity at the age of 6 weeks in rats. The aim of this study was to determine whether NMD followed by adult stress at the age of 6 weeks induces visceral pain in rats and to investigate the roles of adrenergic signaling in visceral pain. Here we showed that NMD rats exhibited visceral hypersensitivity 6 h and 24 h after the termination of adult multiple stressors (AMSs). The plasma level of norepinephrine was significantly increased in NMD rats after AMSs. Whole-cell patch-clamp recording showed that the excitability of dorsal root ganglion (DRG) neurons from NMD rats with AMSs was remarkably increased. The expression of β adrenergic receptors at the protein and mRNA levels was markedly higher in NMD rats with AMSs than in rats with NMD alone. Inhibition of β adrenergic receptors with propranolol or butoxamine enhanced the colorectal distention threshold and application of butoxamine also reversed the enhanced hypersensitivity of DRG neurons. Overall, our data demonstrate that AMS induces visceral hypersensitivity in NMD rats, in part due to enhanced NE-β adrenergic signaling in DRGs.

The Molecular Signatures of Acute-immobilization-induced Antinociception and Chronic-immobilization-induced Antinociceptive Tolerance

In the present study, the productions of antinociception induced by acute and chronic immobilization stress were compared in several animal pain models. In the acute immobilization stress model (up to 1 hr immobilization), the antinociception was produced in writhing, tail-flick, and formalin-induced pain models. In chronic immobilization stress experiment, the mouse was enforced into immobilization for 1 hr/day for 3, 7, or 14 days, then analgesic tests were performed. The antinociceptive effect was gradually reduced after 3, 7 and 14 days of immobilization stress. To delineate the molecular mechanism involved in the antinociceptive tolerance development in the chronic stress model, the expressions of some signal molecules in dorsal root ganglia (DRG), spinal cord, hippocampus, and the hypothalamus were observed in acute and chronic immobilization models. The COX-2 in DRG, p-JNK, p-AMPKα1, and p-mTOR in the spinal cord, p-P38 in the hippocampus, and p-AMPKα1 in the hypothalamus were elevated in acute immobilization stress, but were reduced gradually after 3, 7 and 14 days of immobilization stress. Our results suggest that the chronic immobilization stress causes development of tolerance to the antinociception induced by acute immobilization stress. In addition, the COX-2 in DRG, p-JNK, p-AMPKα1, and p-mTOR in the spinal cord, p-P38 in the hippocampus, and p-AMPKα1 in the hypothalamus may play important roles in the regulation of antinociception induced by acute immobilization stress and the tolerance development induced by chronic immobilization stress.

Tardy Ulnar Nerve Palsy by Neurofibroma

Tardy ulnar nerve palsy is ulnar neuropathy at or around elbow and commonly evaluated in the electromyography laboratory. However, ulnar neuropathy at the elbow due to neurofibroma is rare. Neurofibromas are tumors that arise within nerve fasciculi and anywhere along a nerve from dorsal root ganglion to the terminal nerve branch. We report one case of ulnar neuropathy at the elbow due to neurofibroma. Patient had paresthesia on the left 5th finger and there had been left hypothenar atrophy since 2 months ago. Tinel's sign was positive at left elbow. As a result of electromyography, there were suggestive of right ulnar neuropathy at or around elbow, referred to as tardy ulnar nerve palsy. Ultrasonography showed a diffuse tortuous thickening with multiple neurofibromas arising from individual fascicles of the ulnar nerve in cubital tunnel area. Surgery was then performed to release cubital tunnel of left elbow, then the patient's symptoms improved.

Expression of myo-inositol cotransporters in the sciatic nerve and dorsal root ganglia in experimental diabetes

The transport of myo-inositol is the main mechanism for the maintenance of its high intracellular levels. We aimed to measure the mRNA and protein levels of myo-inositol cotransporters in the sciatic nerve (SN) and dorsal root ganglia (DRG) during experimental diabetes. Streptozotocin-induced (STZ; 4, 8, and 12 weeks; 65 mg/kg; ip) diabetic rats (DB) and age-matched euglycemic (E) rats were used for the analysis of mRNA and protein levels of sodium myo-inositol cotransporters 1, 2 (SMIT1, SMIT2) or H+/myo-inositol cotransporter (HMIT). There was a significant reduction in the mRNA levels for SMIT1 in the SN and DRG (by 36.9 and 31.0%) in the 4-week DB (DB4) group compared to the E group. SMIT2 was not expressed in SN. The mRNA level for SMIT2 was up-regulated only in the DRG in the DB4 group. On the other hand, the protein level of SMIT1 decreased by 42.5, 41.3, and 44.8% in the SN after 4, 8, and 12 weeks of diabetes, respectively. In addition, there was a decrease of 64.3 and 58.0% of HMIT in membrane and cytosolic fractions, respectively, in the SN of the DB4 group. In the DRG, there was an increase of 230 and 86.3% for SMIT1 and HMIT, respectively, in the DB12 group. The levels of the main inositol transporters, SMIT1 and HMIT, were greatly reduced in the SN but not in the DRG. SMIT-1 was selectively reduced in the sciatic nerve during experimental STZ-induced diabetes.