The Effect Of Pulsed Radiofrequency On Dorsal Root Ganglions To CCI And Inflammation Pain Rats And The Efficacy And Safety To Treat Patientswith Postherpetic Neuralgia On Chest And Back

Refractory postherpetic neuralgia (PHN) is always the difficult areas for the study and treatment of chronic pain. Dorsal root ganglion (DRG) cells are the primary afferent neurons of algaesthesis of trunk and extremities. DRG transmits and accommodates sensations and accepts and conveys nociception of the organism, so it plays an important role in occurance and maintenance of neuropathic pain.The small neurons in DRG transmit nociception and are the primary afferent neurons of peripheral nociception signals afferenting to cerebral cortex. The small neurons are closely related to pain transmission mechanism. Navl.8is highly and mainly expressed in small DRG neurons and their efferent nerve C fibers. Navl.8are closely related to inflammatory pain and neuropathic pain mechanism.In addition,It is indicated in recent studies that the activation of microglia and astrocyte in spinal cord may be involved in the pathogenesis of inflammatory pain and neuropathic pain.There are definite analgesic effect of pulsed radiofrequency (PRF) applied to peripheral nervous system in animal experiments and clinical studies, although its analgesic mechanism is not completely clear. The effect of PRF to Navl.8in DRG and had not been reported in literature and the effect of PRF to glial cells such as microglia and astrocytein the spinal cord in CCI and inflammatory pain rats had not been reported. This research is divided into the following three parts:Part OneThe effect of Nav1.8expression by PRF on DRGs in CCI and inflammatory pain rats.Objective:To observe the effect of Navl.8mRNA and protein expression by PRF on DRGs in CCI and inflammatory painrats.Methods:1. Establishment of CCI and inflammatory pain(IP) model in rats.48SD male rats were divided randomly into8groups, six rats per group(n=6). A1(Sham-Sham): CCI sham-operation and RPF sham-operation, A2(Sham-PRF):CCI sham-operation and RPF, A3(CCI-Sham):CCI and RPF sham-operation, A4(CCI-PRF):CCI and PRF. B1(Sham-Sham):IP sham-operation and RPF sham-operation, B2(Sham-PRF):IP sham-operation and PRF, B3(IP-Sham):IP and PRFsham-operation, B4(IP-PRF):IP and RPF.2. Paw withdrawal threshold(PWT) and paw withdrawal latency (PWL) were measured to evaluate mechanical hyperalgesia and thermal hyperalgesia before surgery (To) and1,3,5,7days(T1-T4) after surgery. PRF or PRF sham-operation was performed at4days after surgery.3. RT-PCR for Nav1.8mRNA expression in the right L4-L5DRGs in each group rats.4. Western blot for Navl.8protein expression in the right L4-L5DRGs in in each group rats.Results:1. Changes of behavior in in each group ratsCompared to group Al, PWT and PWL were decreased in group A3and A4at T1-T4(P<0.05). Compared to group A3, PWT and PWL in group A4at T3and T4were increased. Compared to B1, PWT and PWL were decreased in group B3and B4at T1-T4(P<0.05). Compared to group B3, PWT and PWL in group B4at T3and T4were increased.2. Results of RT-PCR:Nav1.8mRNA expression showed a significant decrease in ipsilateral DRGs of A3and A4group compared with A1rats (P<0.05). Compared with A3, Navl.8mRNA expression of A4showed no significant difference (P>0.05). There was no change of Navl.8mRNA expression level in DRGs of A2rats compared with A1(P>0.05). Navl.8mRNA expression showed a significant increase in ipsilateral DRGs of B3and B4group compared with B1rats (P<0.05). Compared with B3, Navl.8mRNA expression decreased in B4rats (P<0.05). There was no change of Nav1.8mRNA expression level in DRGs of B2rats compared with B1(P>0.05). 3. Results of Western blot:Compared to group A1, the Navl.8protein expression in ipsilateral DRGs in group A3and A4were decreased (P<0.05). Compared to A1, the Nav1.8protein expression in A2group showed no significant difference (P>0.05). Compared to A3, there were no significant changes in Navl.8protein expression in A4(P>0.05). Compared to group B1, Navl.8protein expression in group B3B4were increased (P<0.05).Compared to B1, the Nav1.8protein expression in B2group showed no significant difference (P>0.05). Compared to B3, there were no significant changes in Nav1.8protein expression in B4(P>0.05).Conclusions:Mechanical hyperalgesia and thermal hyperalgesia in CCI and inflammatory painrats were inhibited by PRF on DRGs.Nav1.8mRNA and protein expression were significantly decreased in CCI rats, PRF made no difference to Navl.8mRNA and protein expression in CCI rats. Navl.8mRNA and protein expression were significantly increased in IP rats, PRF made a decrese to Nav1.8mRNA expression IP rats.Part TwoThe effect of PRF to glial cells and inflammatory cytokine in the spinal cord in CCI and inflammatory pain rats.Objective:To observe the effect of PRF to mRNA expression of OX42, GFAP, TNF-a, IL-1and IL-6in the spinal cord in CCI and inflammatory pain rats.Methods:1. Establishment of CCI and inflammatory pain (IP) model in rats.48SD male rats were divided randomly into8groups, six rats per group (n=6). A1(Sham-Sham): CCI sham-operation and RPF sham-operation, A2(Sham-PRF):CCI sham-operation and RPF, A3(CCI-Sham):CCI and RPF sham-operation, A4(CCI-PRF):CCI and PRF. B1(Sham-Sham):IP sham-operation and RPF sham-operation, B2(Sham-PRF):IP sham-operation and PRF, B3(IP-Sham):IP and PRF sham-operation, B4(IP-PRF):IP and RPF.2. Paw withdrawal threshold (PWT) and paw withdrawal latency (PWL) were measured to evaluate mechanical hyperalgesia and thermal hyperalgesia before surgery (TO) and1,3,5,7days (T1-T4) after surgery. PRF or PRF sham-operation was performed at4days after surgery.3. RT-PCR for mRNA expression of OX42, GFAP, TNF-α, IL-1and IL-6in the right L4-L5spinal segment in each group rats.Results:The mRNA expression of OX42, GFAP, TNF-aand IL-1showed a significant increase in A3and A4group compared with A1rats (P<0.05). Compared with A3, mRNA expression of OX42、GFAP、TNF-α and IL-1in A4were decreased (P<0.05). There was no significant difference of IL-6mRNA expression in A1-A4groups (P>0.05).The mRNA expression of OX42, GFAP, TNF-α, IL-1and IL-6showed a significant increase in B3and B4group compared with Bl rats (P<0.05). Compared with B3, mRNA expression of OX42, GFAP, TNF-a, IL-1and IL-6in B4were decreased (P<0.05).Conclusions:PRF can decrese the expressionof OX42, GFAP andinflammatorycytokine in spinal cord.Part ThreeClinical research of continuous and pulsed radiofrequency on the dorsal root ganglia for the treatment of postherpetic neuralgia on chest and back under the guidance of CTObjective To evaluate the efficacy and security of continuous and pulsed radiofrequency on dorsal root ganglia for the treatment of postherpetic neuralgia on chest and back under the guidance of3-dimention reconstruction CT.Methods120patients suffering from postherpetic neuralgia in thoracic back region were randomly divided into3groups (n=40each):group C, control group, injection with compound betamethasone simplely. Group CRF, accepted continuous radiofrequency at70℃combined with compound betamethasone and group PRF, accepted pulsed radiofrequency combined with compound betamethasone. Visual Analogue Scale(VAS), sleep interference score (SIS) and a short form of McGill pain questionnaire (SF-MPQ) were used to evaluate the efficacy preoperation (To) and1d,7d,1,3months afteroperation(T1-4).Results Compared with To, VAS, SIS and SF-MPQ scores were significant lower at T1-2in group C and T1-4in group CRF and PRF(P<0.05).Compared with group C, VAS, SIS and SF-MPQ scores were significant lower at T1-4in group CRF and PRF(P<0.05). The recurernce rate at T4in three groups was respectively57%、33%、39%. Hypesthesia respectively appeared in13patients and anesthesia dolorosa appeared in5patients in group CRF.Furthermore1patients in group CRF got nerve injuryed followed with dyskinesia in homolateral lower limb. No severe complication such as nerve and spinal cord injuryed occurred except6patients got slightly hypesthesia in group PRF.Conclusion CRF and PRF on DRG under the guidance of CT for the treatment of PHN on chest and back all achieved exact effect in3months afteroperation. The recurrence rate was lower and complications were more in CRF compared with PRF. PRF was safer with fewer complications.Insummary, PRF on DRGs can attenuate hyperalgesia. PRF can decrese activation of microglia and astrocyteand further inhibit the release of inflammatory factors in the spinal cord to achieve anti-inflammatory and analgesic effect. PRF may affect Navl.8in DRGs of inflammatory pain model rats.