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Objective:To evaluate the role of sphingosine-1-phospho-1 receptor(S1PR1)in the dorsal root ganglion in remifentanil-induced hyperalgesia in rats with incisional pain.Methods:Forty-eight male Sprague-Dawley rats with successful intrathecal and caudal vein catheterization, weighing 260-280 g, aged 2-3 months, were divided into 6 groups ( n= 8 each) using a random number table method: control group (group C), S1PR1 antagonist (FTY720) group (group F), remifentanil group (group R), remifentanil + S1PR1 antagonist (FTY720) group (group R+ F), remifentanil + incisional pain group (group R+ I), and remifentanil + incisional pain + S1PR1 antagonist (FTY720) group (group R+ I+ F). In C group, normal saline 0.1 μg·kg -1·min -1 was intravenously infused for 60 min. In R group, remifentanil 1.0 μg· kg -1·min -1 was infused for 60 min through the caudal vein. In F group, FTY720 3 nmol was intrathecally injected, and 10 min later normal saline 1.0 μg· kg -1·min -1 was infused for 60 min via the caudal vein. In R+ F group, FTY720 3 nmol was intrathecally injected, and 10 min later remifentanil 1.0 μg· kg -1·min -1 was infused for 60 min through the caudal vein. In R+ I group, remifentanil 1.0 μg·kg -1·min -1 was infused for 60 min through the caudal vein while the model of incisional pain was developed. In R+ I+ F group, FTY720 3 nmol was intrathecally injected, 10 min later the incisional pain model was prepared, and remifentanil 1.0 μg·kg -1·min -1 was injected for 60 min through the caudal vein at the same time. The mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) were measured at 24 h before remifentanil or normal saline infusion (T 0) and 2, 6, 24 and 48 h after stopping remifentanil or normal saline infusion (T 1-4). Rats were sacrificed after the last measurement of pain threshold, and the L 4-6 segments of dorsal root ganglion were taken for determination of the expression of S1PR1, NOD-like receptor thermal protein domain-associated protein 3 (NLRP3), interleukin-1β (IL-1β) and glutamate transporter-1 (GLT-1) protein and mRNA (by Western blot and quantitative polymerase chain reaction). Results:Compared with C group, the MWT was significantly decreased and TWL was shortened at T 1-4, the expression of S1PR1, NLRP3 and IL-1β protein and mRNA in dorsal root ganglion was up-regulated, and the expression of GLT-1 protein and mRNA in dorsal root ganglion was down-regulated in R group ( P<0.05), and no significant change was found in the parameters mentioned above in group F ( P>0.05). Compared with R group, MWT was significantly decreased and TWL was shortened at T 1-4, the expression of S1PR1, NLRP3 and IL-1β protein and mRNA in dorsal root ganglion was up-regulated, and GLT-1 protein and mRNA expression in dorsal root ganglion was down-regulated in R+ I group, and MWT was significantly increased and TWL was prolonged at T 1-4, the expression of S1PR1, NLRP3 and IL-1β protein and mRNA in the dorsal root ganglion was down-regulated, and GLT-1 protein and mRNA expression in the dorsal root ganglion was up-regulated in R+ F group ( P<0.05). Compared with R+ I group, MWT was significantly increased and TWL was prolonged at T 1-4, the expression of S1PR1, NLRP3 and IL-1β protein and mRNA in the dorsal root ganglion was down-regulated, and the expression of GLT-1 protein and mRNA in the dorsal root ganglion was up-regulated in R+ I+ F group( P<0.05). Conclusions:The mechanism by which remifentanil induces hyperalgesia is associated with up-regulation of S1PR1 expression, activation of inflammatory factors, and down-regulation of GLT-1 expression in the rats with incisional pain.
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Objective:To investigate effects of the autophagy inducer rapamycin and autophagy inhibitor 3-methyladenine on viral structures and biosynthesis of functional proteins in dorsal root ganglia in a guinea pig model of varicella-zoster virus (VZV) infection, and to explore their possible mechanisms.Methods:VZV was cultured and proliferated in human embryonic lung fibroblasts (HELFs) , and peripheral blood mononuclear cells (PBMCs) were isolated from guinea pigs. VZV-HELFs and PBMCs were co-cultured for 18-20 hours, and VZV-PBMCs were collected by centrifugation. Thirty-two guinea pigs were randomly and equally divided into 4 groups (8 mice in each group) : blank control group was injected with autologous PBMCs via the medial canthal venous plexus; autophagy inhibition group, autophagy induction group, and VZV infection group were intraperitoneally injected with 3 mg/kg 3-methyladenine solution, 0.5 mg/kg rapamycin solution, and the same volume of 0.9% NaCl solution respectively, followed 2 hours later by injections with 50 μl of VZV-PBMCs via the medial canthal venous plexus. Fourteen days later, the guinea pigs in each group were sacrificed, and dorsal root ganglion tissues were collected. The transmission electron microscope was used to observe the morphology of virus particles, as well as the morphology and number of autophagic vesicles, Western blot analysis was performed to determine the expression of VZV nucleocapsid protein (NCP) , immediate-early protein 62 (IE62) , and autophagy-related proteins Beclin-1 and p62, and immunohistochemical study to determine the expression of anti-VZV antibodies in VZV-infected dorsal root ganglia. Statistical analysis was carried out by using two-independent-sample t test, one-way analysis of variance, least significant difference- t test or Kruskal-Wallis H test. Results:Nucleocapsid-containing virions and scattered autophagosomes were seen in the dorsal root ganglia in the VZV infection group under the transmission electron microscope. The number of autophagic vesicles significantly differed among the blank control group, VZV infection group, autophagy induction group and autophagy inhibition group ( M[ Q1, Q3]: 0, 5[4, 6], 7[5, 9], 0, respectively; H = 135.60, P < 0.01) , and was significantly higher in the VZV infection group than in the blank control group and autophagy inhibition group (both P < 0.05) , as well as in the autophagy induction group than in the autophagy inhibition group ( P<0.05) , but there was no significant difference between the VZV infection group and autophagy induction group ( P>0.05) . Western blot analysis showed that the expression level of IE62 protein was significantly higher in the VZV infection group (1.49 ± 0.06) than in the blank control group (0.50 ± 0.09, t = 9.17, P < 0.05) ; the expression of anti-VZV antibodies was significantly lower in the autophagy inhibition group than in the autophagy induction group and VZV infection group ( t = 9.24, 7.78, respectively, both P < 0.01) , while there was no significant difference between the autophagy induction group and VZV infection group ( P > 0.05) . Conclusion:Autophagy occurred in the dorsal root ganglia of guinea pigs after VZV infection; the inhibition of autophagy could affect the structure of VZV and decrease the expression of VZV functional proteins in the dorsal root ganglia of guinea pigs.
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Objective:To evaluate the role of ferroptosis in the dorsal root gangions in neuropathic pain (NP) in rats.Methods:Thirty-two healthy male Sprague-Dawley rats, aged 6-8 weeks, weighing 180-220 g, were randomized into 4 groups ( n=8 each) using a random number table method: sham operation group (Sham group), NP group, NP+ solvent control group (NP+ Veh group), and NP+ liproxstatin-1 (Lip-1) group (NP+ Lip group). NP was induced by chronic constrictive injury (CCI) to sciatic nerve in anesthetized animals.In NP+ Lip group, liproxstatin-1 (diluted to 10 μg/μl in DMSO) 30 μl was intrathecally injected for 3 consecutive days after surgery.NP+ Veh group received intrathecal injection of DMSO 30 μl for 3 consecutive days after surgery.Mechanical withdrawal threshold (MWT) and thermal withdrawal latency (TWL) were measured at 3 days before surgery and on days 1, 3, 5, 7 and 10 after surgery.Rats were sacrificed after the end of pain threshold measurement on day 10 after surgery, and DRGs of the lumbar segment (L 3-5) on the left side were removed for determination of the levels of iron ion, reactive oxygen species (ROS), malondialdehyde (MDA), glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD), expression of glutathione peroxidase 4 (GPX4) and acyl-CoA synthetase long-chain family member 4 (ACSL4) (by Western blot), and expression of ACSL4 in each nerve cells of DRGs (by immunofluorescence) and for microscopic examination of the ultrastructure of mitochondria in DRGs (by transmission electron microscopy). Results:Compared with Sham group, MWT was significantly decreased and TWL was shortened at T 2-6, levels of iron ions, ROS and MDA in DGRs were increased, activities of SOD and GSH-Px were decreased, ACSL4 expression was up-regulated, GPX4 expression was down-regulated, and ACSL4 expression in astrocytes and Schwann cells of DRGs was up-regulated in NP group ( P<0.05). Compared with NP group, MWT was significantly increased and TWL was prolonged at T 3-6, levels of iron ions, ROS and MDA in DGRs were decreased, activities of SOD and GSH-Px were increased, ACSL4 expression was down-regulated, GPX4 expression was up-regulated, and ACSL4 expression in astrocytes and Schwann cells of DRGs was down-regulated ( P<0.05), and no significant change was found in the parameters mentioned above in NP+ Veh group ( P>0.05). The results of electron microscopy showed that collapsed mitochondrial cristae and membrane rupture were found in astrocytes and Schwann cells of DRGs in NP group, and the number of collapsed mitochondrial cristae and membrane rupture was significantly decreased in NP + Lip group when compared with NP group. Conclusions:The ferroptosis in DRGs is involved in NP in rats.
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Objective:To evaluate the role of Nod-like receptor family pyrin domain-containing 3 (NLRP3) in the dorsal root ganglion (DRG) in persistent postoperative pain in rats.Methods:Forty-eight male Sprague-Dawley rats, in which IT catheters were successfully implanted, weighing 200-250 g, aged 2-3 months, were divided into 4 groups ( n=12 each) using a random number table method: sham operation group (S group), persistent postoperative pain group (P group), persistent postoperative pain+ NLRP3-siRNA group (P+ siRNA group) and persistent postoperative pain+ NLRP3-scrRNA group (P+ scrRNA group). A persistent postoperative pain model was established by skin/muscle incision and retraction (SMIR) in anesthetized animals.Normal saline 10 μl were intrathecally injected in S group and P group, NLRP3-siRNA 10 μl and NLRP3-scrRNA 10 μl were intrathecally injected in CP+ siRNA group and CP+ scrRNA group, respectively, at 3 days before operation.The mechanical paw withdrawal threshold (MWT) was measured at 1 day before operation (T 0) and 1, 5, 10, 15 and 20 days after operation (T 1-5). Six rats in each group were randomly selected and sacrificed at T 3, and the L 4-5 DRGs on the operated side were harvested for determination of the expression of NLRP3 and caspase-1 (by Western blot), NLRP3 mRNA expression (by real-time polymerase chain reaction) and content of interleukin-1beta (IL-1β) (by enzyme-linked immunosorbent assay). Results:Compared with group S, the MWT was significantly decreased at T 2-5, the expression of NLRP3 protein and mRNA in DRGs was up-regulated, and the content of IL-1β was increased in group P ( P<0.05). Compared with group P, the MWT was significantly increased at T 2-5, the expression of NLRP3 protein and mRNA and caspase-1 was down-regulated, and the content IL-1β was decreased in group P+ siRNA ( P<0.05), and no significant change was found in the parameters mentioned above in group P+ scrRNA ( P>0.05). Conclusion:NLRP3 in DRGs is involved in the development of persistent postoperative pain, and the mechanism may be related to the development of NLPR3 inflammasomes which further induces peripheral neuroinflammatory response in rats.
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Objective:To evaluate the role of nucleotide-binding oligomerization domain-2 (NOD2) in dorsal root ganglion in the development of neuropathic pain (NP) in rats.Methods:Thirty-two adult male SPF Sprague-Dawley rats, weighing 240-260 g, aged 2-3 months, were divided into 4 groups ( n=8 each) using a random number table method: control group (group C), NP group (group S), negative control siRAN group (group N), and NOD2-siRNA group (group R). In N and R groups, 1×10 8 IFU/ml negative control siRNA and NOD2-siRNA 10 μl were intrathecally injected, respectively, once a day for 3 consecutive days.Normal saline 10 μl was intrathecally injected once a day for 3 consecutive days in C and S groups.The model of NP was established using spared nerve injury (SNI) at 2 weeks after intrathecal injection.The mechanical paw withdrawal threshold (MWT) was measured at 1 day before surgery and 1, 3, 7, 10, 14 and 28 days after SNI.Animals were sacrificed after measuring pain threshold on day 28, and the dorsal root ganglions (DRGs) of the lumbar segment (L 4-6) were removed for determination of the expression of NOD2 (by Western blot) and expression of tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β), IL-6 and NOD2 mRNA (using quantitative real-time polymerase chain reaction). Results:Compared with group C, MWT was significantly decreased at each time point after SNI, and the expression of NOD2 protein and mRNA and TNF-α, IL-1β and IL-6 mRNA in DRGs was up-regulated in group NP ( P<0.01). Compared with group NP, MWT was significantly increased at each time point after SNI, and the expression of NOD2 protein and mRNA and TNF-α, IL-1β and IL-6 mRNA in DRGs was down-regulated in group R ( P<0.01), and no significant change was found in the parameters mentioned above in group N ( P>0.05). Conclusion:The mechanism underlying the development of NP may be related to the up-regulation of NOD2 expression in DRGs, thus further promoting the expression of pro-inflammatory factors in rats.
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Objective:To evaluate the relationship between the euchromatic histone-lysine N-methyltransferase (G9a) and sodium-dependent activation of potassium channel (Slack) in the dorsal root ganglia (DRG) of rats with neuropathic pain (NP).Methods:Forty-eight clean-grade healthy male Sprague-Dawley rats, aged 1 month, weighing 100-120 g, were divided into 4 groups ( n=12 each) by a random number table method: sham operation group (S group), vector plus sham operation group (VS group), vector plus NP group (VN group), and G9a CRISPR/Cas9 knockout plus NP group (GN group). Sham operation was performed at the age of 2 months in group S. In group VS, AAV5 1 μl was microinjected into L 4 and L 5 DRG at the age of 1 month, and sham operation was performed at the age of 2 months.In VN group and GN group, AAV5 and G9a CRISPR/Cas9 knockout plasmid 1 μl were microinjected into L 4 and L 5 DRG at the age of 1 month, and NP model was established by spinal nerve ligation (SNL) at the age of 2 months.Six rats in each group were selected to measure the mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) before microinjection (T 0), before SNL (T 1), and at 3, 5 and 7 days after SNL (T 2-4). The animals were sacrificed after the last behavioral testing, the DRGs of lumbar segment (L 4, 5) were removed for determination of the expression of G9a, dimethylation of histone H3 at lysine 9(H3K9me2) and Slack (by Western blot). At 7 days after establishing the model, 6 rats from each group were selected to culture the primary DRG neurons.The frequency and amplitude of Slack current in DRG neurons and miniature excitatory post-synaptic currents (mEPSCs) in the spinal dorsal horn were measured by whole-cell patch-clamp technique. Results:Compared with group S, the TWL was significantly shortened and the MWT was decreased at T 2-4, the expression of G9a and H3K9me2 in the spinal dorsal horn was up-regulated, the expression of Slack was down-regulated, the amplitude and frequency of Slack currents in DRG neurons were decreased, and the frequency of mEPSCs was increased in group VN ( P<0.05), and no significant change was found in the parameters mentioned above in group VS ( P>0.05). Compared with group VN, the TWL was significantly prolonged and the MWT was increased at T 2-4, the expression of G9a and H3K9me2 in the spinal dorsal horn was down-regulated, the expression of Slack was up-regulated, the amplitude and frequency of Slack currents in DRG neurons were increased, and the frequency of mEPSCs was decreased in group GN ( P<0.05). Conclusion:The mechanism of NP is related to up-regulating the expression of G9a in DRG, thus inhibiting the expression and opening of Slack channels in rats.
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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.
Subject(s)
Humans , Spine , Magnetic Resonance Imaging , Minimally Invasive Surgical Procedures , Ganglia, Spinal , AnatomyABSTRACT
BACKGROUND: Pulsed radiofrequency (PRF) is a treatment modality that alleviates radicular pain by intermittently applying high-frequency currents adjacent to the dorsal root ganglion. There has been no comparative study on analgesic effect according to the position of the needle tip in PRF treatment. The objective of this study is to evaluate the clinical outcomes of PRF according to the needle tip position. METHODS: Patients were classified into 2 groups (group IP [group inside of pedicle] and group OP [group outside of pedicle]) based on needle tip position in the anteroposterior view of fluoroscopy. In the anteroposterior view, the needle tip was advanced medially further than the lateral aspect of the corresponding pedicle in group IP; however, in group OP, the needle tip was not advanced. The treatment outcomes and pain scores were evaluated at 4, 8, and 12 weeks after applying PRF. RESULTS: At 4, 8, and 12 weeks, there were no significant differences between the successful response rate and numerical rating scale score ratio. CONCLUSIONS: The analgesic efficacy of PRF treatment did not differ with the needle tip position.
Subject(s)
Humans , Analgesics , Fluoroscopy , Ganglia, Spinal , Low Back Pain , Lumbosacral Region , Needles , Observational Study , Pulsed Radiofrequency Treatment , Radiculopathy , Retrospective Studies , Spinal Nerve RootsABSTRACT
BACKGROUND: Several nerve blocks can reduce the incidence of postherpetic neuralgia (PHN) as well as relieve acute zoster-related pain, but the long-term outcome of PHN has not been clearly determined. This study investigated the efficacy of selective nerve root block (SNRB) for herpes zoster (HZ) on the long-term outcome of PHN. METHODS: We prospectively conducted an interview of patients who had undergone an SNRB for HZ from January 2006 to December 2016 to evaluate their long-term PHN status. The relationship between the time from HZ onset to the first SNRB and the long-term outcome of PHN was investigated. RESULTS: The data of 67 patients were collected. The patients were allocated to acute (SNRB ≤ 14 days, n = 16) or subacute (SNRB > 14 days, n = 51) groups. The proportions of cured patients were 62.5% and 25.5% in the acute and subacute groups (P = 0.007), respectively. In logistic regression, an SNRB >14 days was the significant predictor of PHN (adjusted odd ratio, 3.89; 95% confidence interval, 1.02–14.93; P = 0.047). Kaplan–Meier analysis revealed that time from the SNRB to the cure of PHN was significantly shorter in the acute group (2.4 ± 0.7 yr) than in the subacute group (5.0 ± 0.4 yr; P = 0.003). CONCLUSIONS: An early SNRB during the acute stage of HZ (within 14 days) appears to decrease the incidence and shorten the duration of PHN, with a median of 5.0 years of follow-up.
Subject(s)
Humans , Follow-Up Studies , Ganglia, Spinal , Herpes Zoster , Incidence , Logistic Models , Nerve Block , Neuralgia, Postherpetic , Prospective StudiesABSTRACT
Objective To evaluate the relationship between hydrogen sulfide (H2S) and P2X3 receptors in dorsal root ganglions (DRGs) of rats with neuropathic pain (NP).Methods Thirty-six healthy male Sprague-Dawley rats,aged 4-6 weeks,weighing 180-200 g,in which IT catheters were successfully implanted,were divided into 3 groups (n=12 each) using a random number table method:sham operation group (group S),group NP and endogenous H2S synthase (cystathionine beta-syntheses [CBS]) inhibitor animooxyacetic acid (AOAA) group (group A).NP was induced by chronic constriction injury (CCI) to the sciatic nerve at 3 days after IT catheters were successfully implanted.AOAA (10 μg/kg) 10 μl and normal saline 10 μl were intrathecally injected once a day for 14 consecutive days starting from 1 day after CCI in group A,and normal saline 20 μl was intrathecally injected instead in S and NP groups.At 1 day before CCI and 1,3,7,10 and 14 days after CCI,the thermal paw withdrawal latency (TWL) and mechanical paw withdrawal threshold (MWT) were measured at 30 min after intrathecal injection.The animals were sacrificed at 7 and 14 days after CCI,and ipsilateral DRGs of the lumbar segment (L4-6) were removed for detection of the expression of CBS and P2X3 receptors by Western blot.Results Compared with group S,the TWL was significantly shortened,MWT was decreased,and the expression of CBS and P2X3 receptors in DRGs was up-regulated at each time point after CCI in group NP (P＜0.05).Compared with group NP,the TWL was significantly prolonged,the MWT was increased,and the expression of CBS and P2X3 receptors in DRG s was down-regulated at each time point after CCI in group A (P＜0.05).Conclusion H2S in DRG s can up-regulate the expression of P2X3 receptors,which may be involved in the pathophysiological mechanism of NP in rats.
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Abstract Purpose: To evaluate the role of CX3CL1 and NF-κB in the lumbar disc herniation induced neuropathic pain. Methods: After LDH induced by implantation of autologous nucleus pulposus (NP) on the left L5 nerve root was established, mechanical thresholds and thermal hyperalgesia were tested at relevant time points during an observation period of 28 days. Expression of CX3CL1 and NF-κBin the dorsal root ganglion (DRG) were performed by using Western blotting and RT-PCR. Results: Implantation of autologous nucleus pulposus (NP) induced neuropathic pain, associated with increased mRNA and protein expression of CX3CL1 in the DRG. Moreover, intrathecal injection of neutralizing antibody against CX3CL1 could attenuates LDH-induced persistent pain hypersensitivity. Interestingly, NF-κB activation in the DRGs were found in LDH-induced neuropathic pain. Furthermore, NF-κB downregulation by p65 inhibitor PDTC markedly alleviated LDH-induced mechanical allodynia and thermal hyperalgesia in rat. Importantly, CX3CL1 neutralizing antibody (10 μg/10 μl, i.t.) reduces p-p65 protein level in DRG Conclusions: CX3XL1 could regulate LDH-induced neuropathic pain through NF-κB pathway. Targeting CX3CL1 and NF-κB may represent a potential treatment for neuropathic pain caused by LDH.
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Animals , Male , NF-kappa B/metabolism , Chemokine CX3CL1/metabolism , Ganglia, Spinal/metabolism , Intervertebral Disc Displacement/metabolism , Neuralgia/etiology , Neuralgia/metabolism , Time Factors , Behavior, Animal , Down-Regulation , Blotting, Western , NF-kappa B/analysis , Rats, Sprague-Dawley , Disease Models, Animal , Chemokine CX3CL1/analysis , Real-Time Polymerase Chain Reaction , Hyperalgesia/metabolism , Intervertebral Disc Displacement/complicationsABSTRACT
Objective To evaluate the effect of application of pulsed radiofrequency to dorsal root ganglia on activation of spinal astrocytes in a rat model of neuropathic pain (NP).Methods Eighty male Sprague-Dawley rats,aged 6-8 weeks,weighing 200-250 g,were divided into 4 groups (n=20 each) using a random number table method:sham operation group (group Sham),group NP,pulsed radiofrequency group (PRF group) and sham pulsed radiofrequency group (group SPRF).NP was induced by chronic constriction injury (CCI).The mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) were measured at 1 day before CCI and 1,7,14 and 21 days after CCI.Four rats were sacrificed at 1 day before CCI and 14 and 21 days after CCI,and the L4.6 segments of the spinal cord were harvested to detect the expression of glial fibrillary acidic protein (GFAP) and interleukin-1beta (IL-1β) by Western blot.Results Compared with group Sham,the MWT was significantly decreased and the TWL was shortened at each time point after CCI,and the expression of GFAP and IL-1β was up-regulated at 14 and 21 days after CCI in NP,PRF and SPRF groups (P＜0.05).Compared with group NP,the MWT was significantly increased and the TWL was prolonged at 14 and 21 days after CCI (P＜0.05),and the expression of GFAP and IL-1β was down-regulated at 14 and 21 days after CCI in group PRF (P＜0.05),and no significant change was found in the parameters mentioned above in group SPRF (P＞0.05).Conclusion The mechanism by which pulsed radiofrequency reduces NP is probably related to inhibiting spinal astrocyte activation in rats.
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Objective To evaluate the role of protein kinase C in the maintenance of chronic inflammatory pain in rats and the relationship with the expression of Nav1.8 in the dorsal root ganglion (DRG).Methods Thirty pathogen-free healthy female Sprague-Dawley rats,weighing 180-220 g,were divided into 3 groups using a random number table:control group (group C),chronic inflammatory pain group (group CIP) and PKC inhibitor group (group P).Normal saline 20 μl was injected into the plantar surface of the right hindpaw every day for 14 consecutive days in group C.Prostaglandin E2 100 ng was injected into the plantar surface of the right hindpaw every day for 13 consecutive days to establish the model of chronic inflammatory pain,and dimethyl sulfoxide 20μl was injected into the plantar surface of the right hindpaw on 14th day in group CIP.Prostaglandin E2 100 ng was injected into the plantar surface of the right hindpaw every day for 13 consecutive days,and PKC inhibitor GF1O9203X 100 nmol/20 μl was injected into the plantar surface of the right hindpaw on 14th day in group P.The mechanical paw withdrawal threshold (MWT) was measured at 1 day before injection (T0) and 1,3,7 and 14 days after the last injection (T1-4).The DRGs of the lumbar segment (L4.5) were removed for determination of Nav1.8 expression using immunofluorescence and Western blot.Results Compared with group C,the MWT was significantly decreased at T1-4 in CIP and P groups,and the expression of Nav1.8 in DRGs was significantly up-regulated in group CIP (P＜0.05).Compared with group CIP,the MWT was significantly increased at T4,and the expression of Nav1.8 in DRGs was down-regulated in group P (P＜0.05).Conclusion Up-regulated expression of Nav1.8 after PKC activation in DRGs is involved in the maintenance of chronic inflammatory pain in rats.
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Objective To evaluate the changes in the expression of isolectin B4 (IB4) and calcium gene-related peptide (CGRP) in neurons in dorsal root ganglion (DRG) of rats with neuropathic pain (NP).Methods Forty healthy male Sprague-Dawley rats,weighing 250-280 g,were divided into 2 groups (n =20 each) using a random number table method:solvent group (group S) and group NP.NP was induced by intraperitoneally injecting resiniferatoxin 210 μg/kg,and the solvent of resiniferatoxin was intraperitoneally injected in group S.The mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) were measured in 5 rats selected before establishing the model and at 1,3,7 and 42 days after establishing the model.Five rats were sacrificed at 1,3,7 and 42 days after establishing the model,and the L4-6 segments of the DRGs were removed to determine the expression of CGRP and IB4 in neurons using immunofluorescence.Results Compared with the baseline before establishing the model,the MWT was signilicantly decreased at 3,7 and 42 days after establishing the model,and the TWL was prolonged at 1,3,7 and 42 days after establishing the model in group NP (P＜0.05).Compared with group S,the MWT was significantly decreased at 3,7 and 42 days after establishing the model,the TWL was prolonged at 1,3,7 and 42 days after establishing the model,and the expression of IB4 and CGRP in neurons in DRGs was down-regulated at 1,3,7 and 42 days after establishing the model in group NP (P＜0.05).Conclusion Down-regulated expression of IB4 expression in neurons in DRGs may be involved in the development and maintenance of mechanical hypersensitivity to pain,and down-regulated expression of CGRP may be involved in the development and maintenance of thermal analgesia in rats with NP.
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Objective To evaluate the effect of oxycodone on function of GABAA receptors in dor-sal root ganglion ( DRG ) neurons of rats with neuropathic pain ( NP ) . Methods Thirty-six adult male Sprague-Dawley rats, weighing 180-220 g, aged 10 weeks, were allocated into 3 groups ( n=12 each) u-sing a random number table method: sham operation group ( group S ) , group NP and oxycodone group ( group O) . The sciatic nerve was only isolated but not ligated in group S. NP was induced by chronic con-striction injury. The sciatic nerve was exposed and 4 loose ligatures were placed on the sciatic nerve at 1 mm intervals with 4-0 chromic catgut. Oxycodone 15μg∕kg was intraperitoneally injected once a day for 14 con-secutive days from ligating the sciatic nerve to satisfaction in group O. The thermal paw withdrawal latency( TWL) was measured at 1 day before establishing the model ( T0 ) and 3, 5, 7, 10 and 14 days after es-tablishing the model ( T1-5 ) . The rats were sacrificed after measurement of pain threshold at T5 , and DRG neurons were acutely isolated for recording the amplitude of GABAA receptors-activated currents using whole-cell patch-clamp technique. Results Compared with group S, the TWL was significantly shortened at T1-5, and the amplitude of GABAA receptors-activated currents in DRG neurons was decreased in NP and O groups (P<0. 05). Compared with group NP, the TWL was significantly prolonged at T1-5, and the ampli-tude of GABAA receptors-activated currents in DRG neurons was increased in group O ( P<0. 05) . Conclu-sion Oxycodone can enhance the function of GABAA receptors-activated currents in DRG neurons and thus enhance GABAA receptors-mediated presynaptic inhibition, which may be related to the mechanism of oxyc-odone-induced reduction of NP in rats.
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Objective To evaluate the changes in the expression of gamma-aminobutyric acid (GABA) receptor subunit genes in the dorsal root ganglia (DRG) in a mouse model of neuropathic pain. Methods Experiment Ⅰ Twenty-four male C57BL6 mice, aged 8 weeks, weighing 25-30 g, were di-vided into sham operation group (group Sham, n=12) and neuropathic pain group (group NP, n=12) by using a random number table method. Neuropathic pain was produced by bilateral L4 spinal nerve ligation in anesthetized mice in group NP . The mechanical pain threshold of bilateral hindpaws was measured at 1 day before establishing the model and 7 days after establishing the model. Mice were then sacrificed and DRGs of the bilateral L4 were removed to perform transcriptome sequencing and to analyze the expression of GABA receptor subunit genes. Experiment Ⅱ Twenty-four male C57BL6 mice, aged 8 weeks, weighing 25-30 g, were studied. Neuropathic pain was produced by the left L4 spinal nerve ligation in anesthetized mice. Six mice were selected at 1 day before establishing the model and 3, 7 and 14 days after establishing the model, and the mechanical pain threshold of the left hindpaw was measured. Mice were then sacrificed and DRGs of the left L4 were removed to verify the expression of differentially expressed GABA receptor subunitgenes described in experiment Ⅰby quantitative real-time polymerase chain reaction. Results ExperimentⅠ Compared with group Sham, the mechanical pain threshold was significantly increased, the expression of Gabra1, Gabra2, Gabrb3, Gabrg2, Gabbr1 and Gabbr2 in DRGs was down-regulated, and the expres-sion of Gabrg1 in DRGs was up-regulated at 7 days after establishing the model in group NP ( P<0. 05 or 0. 01) . Experiment Ⅱ Compared with the baseline at 1 day before establishing the model, the mechanical pain threshold was significantly increased, and the expression of Gabra1, Gabra2, Gabrb3, Gabrg2, Gab-br1 and Gabbr2 in DRGs was down-regulated at each time point after establishing the model ( P<0. 05 or 0. 01) , and no significant change was found in the expression of Gabrg1 in DRGs at each time point after establishing the model ( P>0. 05) . Conclusion The expression of GABA receptor subunit genes Gabra1, Gabra2, Gabrb3, Gabrg2, Gabbr1 and Gabbr2 in DRGs is down-regulated, and the expression of Gabrg1 in DRGs is up-regulated in a mouse model of neuropathic pain.
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Objective To investigate the changes in the expression of Ca2+/calmodulin-dependent protein kinase Ⅱ α (CaMK Ⅱ α) in the spinal cord and dorsal root ganglia (DRG) during remifentanil-induced hyperalgesia in a rat model of incisional pain (IP).Methods Thirty-two male Sprague-Dawley rats in which caudal vein catheter was successfully placed,aged 260-280 g,were divided into 4 groups (n=8 each) using a random number table method:control group (group C),IP group,remifentanil group (group R) and remifentanil plus IP group (group RIP).Normal saline was infused via the caudal vein for 60 min at a rate of 0.1 ml · kg-1 · min-1 in group C.Normal saline was infused via the caudal vein for 60 min at a rate of 0.1 ml · kg-1 · min-1,and the model of IP was simultaneously established in group IP.Remifentanil was infused via the caudal vein for 60 min at a rate of 1.0 μg · kg-1 · min-1 in group R.Remifentanil was infused via the caudal vein for 60 min at a rate of 1.0 μg · kg-1 · min-1,and the model of IP was simultaneously established in group RIP.Mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) were measured at 24 h before infusion and 2,6,24 and 48 h after infusion (T0-4).The rats were sacrificed after the last behavioral test,and L4-6 segment of the spinal cord and DRGs were removed for determination of the expression of total and phosphorylated CaMK Ⅱ α (tCaMK Ⅱ α,pCaMK Ⅱ α) by Western blot.The ratio of pCaMK Ⅱ /tCaMK Ⅱ α was calculated.Results Compared with group C,MWT was significantly decreased,TWL was shortened,the expression of tCaMK Ⅱ α and pCaMK Ⅱ α in the spinal cord and DRGs was up-regulated,and the ratio of pCaMK Ⅱ α/tCaMK Ⅱ α was increased in I,R and RIP groups (P＜0.05 or 0.01).Compared with group IP and group R,MWT was significantly decreased,TWL was shortened,the expression of tCaMK Ⅱ α and pCaMK Ⅱ α in the spinal cord and DRGs was up-regulated,and the ratio of pCaMK Ⅱ α/tCaMK Ⅱ α was increased in group RIP (P＜0.05 or 0.01).Conclusion The mechanism by which remifentanil induces hyperalgesia may be related to upregulated expression of CaMK Ⅱ α in the spinal cord and DRGs in a rat model of IP.
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ABSTRACT The authors present an historical review about the main contributions of Professor Derek Denny-Brown to neurology. Some of his achievements include the first description of sensory neuronopathies, and some of the essential textbooks on the function and anatomy of the basal ganglia. In 2016, on the 35th anniversary of his death, modern neurologists are still strongly influenced by his legacy.
RESUMO Os autores apresentam uma revisão histórica sobre as principais contribuições do Professor Derek Denny-Brown à neurologia. Suas realizações incluem a primeira descrição da neuronopatia sensitiva e alguns dos livros fundamentais acerca da função e anatomia dos núcleos da base. Em 2016, ano do seu 35o aniversário de falecimento, os neurologistas atuais ainda são fortemente influenciados pelo seu legado.
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History, 20th Century , Neurology/history , New ZealandABSTRACT
Objective To evaluate the role of transient receptor potential channel 8 (TRPM8) in the development and maintenance of neuropathic pain and the relationship with nuclear factor kappa B (NF-κB) in the dorsal root ganglion of rats.Methods Thirty-six pathogen-free healthy adult male SpragueDawley rats,weighing 180-200 g,aged 6-8 weeks,were divided into 3 groups (n=12 each) using a random number table:sham opeation group (group S),neuropathic pain group (group NP) and TRPM8 bocker BCTC group (group BCTC).Neuropathic pain was induced by ligation of the right sciatic nerve in anesthetized rats.BCTC 20 nmol was intrathecally injected once a day on preoperative day 1 and postoperative days 1,3,7 and 10 in group BCTC.The thermal,mechanical and cold pain thresholds were measured on preoperative day 1 and postoperative days 1,3,7,10 and 14.The dorsal root ganglions of the lumbar segment (L4-6) were removed on postoperative days 7 and 14 for determination of the expression of TRPM8 and NF-κB p65 by Western blot.Results Compared with group S,the thermal and mechanical thresholds were significantly decreased on postoperative days 1-14,and the cold pain threshold was decreased on postoperative days 3-14 in NP and BCTC groups,the expression of TRPM8 and NF-κB p65 in dorsal root ganglions was up-regulated on postoperative days 7 and 14 in group NP (P＜0.05),and no significant change was found in the expression of TRPM8 and NF-κB p65 in dorsal root ganglions in group BCTC (P＞0.05).Compared with group NP,the thermal pain threshold was significantly decreased and the cold pain threshold was increased on postoperative days 3-14,the expression of TRPM8 and NF-κB p65 in dorsal root ganglions was up-regulated on postoperative days 7 and 14,and no significant change was found in the mechanical pain threshold in group BCTC (P＞0.05).Conclusion NF-κB activation after opening of TR-PM8 in dorsal root ganglion neurons is involved in the development and maintenance of neuropathie pain in rats.
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Objective To evaluate the relationship between cold hyperalgesia and trafficking of transient receptor potential melastatin 8 (TRPM8) to cell membrane in the dorsal root ganglion (DRG) of rats with neuropathic pain (NP).Methods Ninety-six healthy male Sprague-Dawley rats,aged 10-12 weeks,weighing 250-280 g,were divided into sham operation group (S group,n=48) and NP group (n =48) using a random number table.NP was produced by chronic constriction injury to the sciatic nerve.The number of paw lifts on the cold plate and mechanical paw withdrawal threshold (MWT) were measured on 1 day before operation and 1,4,7,10 and 14 days after operation.Rats were sacrificed after behavioral testing,and ipsilateral DRGs of the lumbar segment (L46) were dissected tor detection of the expression of TRPM8 in total and membrane proteins by Western blot,and the ratio of TRPM8 expression in the membrane protein to that in the total protein (m/t ratio) was calculated.Results Compared with group S,the number of paw lifts on the cold plate was significantly increased,the MWT was decreased,the expression of TRPM8 in total and membrane proteins was up-regulated,and m/t ratio was increased on postoperative days 4,7,10 and 14 in group NP (P＜0.05 or 0.01).In group NP,the number of paw lifts on the cold plate was gradually increased with the prolongation of time after operation and reached the peak on postoperative day 10,maintaining at the peak until postoperative day 14;the MWT was gradually decreased and reached the lowest level on postoperative day 10,maintaining at the lowest level until postoperative day 14;the expression of TRPM8 in total and membrane proteins and m/t ratio were gradually increased with the prolongation of time after operation and reached the peak on postoperative day 10,maintaining at the peak level until postoperative day 14 (P＜0.01).Conclusion The mechanism underlying the development of cold hyperalgesia is related to enhanced trafficking of TRPM8 to cell membrane in DRGs of rats with NP.