Objective:To evaluate the role of splenic sympathetic nerve-regulated infiltration and polarization of dorsal root ganglion (DRG) macrophages in diabetic neuropathic pain (DNP) in mice.Methods:Forty-eight specific pathogen-free male C57BL/6 mice, aged 6 weeks, weighing 20-22 g, were divided into 4 groups ( n=12 each) using a random number table method: control group (Con group), DNP group, DNP plus sham operation group (DNP+ Sham group), and diabetes mellitus induced by DNP plus splenic sympathetic denervation group (DNP+ SS group). In DNP+ SS group, the splenic sympathetic denervation procedures were performed using 6-hydroxydopamine solution, while a solvent of 0.2% ascorbic acid saline solution was used as a substitute for 6-hydroxydopamine solution in DNP+ Sham group. After a two-week recovery, the diabetes mellitus was induced by intraperitoneal injection of streptozotocin 120 mg/kg in mice at 8 weeks of age. The mechanical paw withdrawal threshold (MWT) were measured on day 1 before developing the model and on days 7, 14, 21 and 28 after developing the model. After the last behavioral testing, the DRG was taken after anesthesia for determination of the expression of the macrophage marker ionized calcium-binding adaptor molecule 1(Iba1), calcitonin gene-related peptide (CGRP), and tumor necrosis factor-α (TNF-α) (by immunofluorescence) and expression of M1 phenotype markers (CD16, TNF-α, inducible nitric oxide synthase [iNOS]) and M2 phenotype markers (interleukin-10 [IL-10], transforming growth factor-β1 [TGF-β1], and CD206) mRNA (using quantitative real-time polymerase chain reaction). Results:Compared with Con group, the MWT was significantly decreased on days 14, 21 and 28 after developing the model, the expression of CGRP and TNF-α in the DRG was up-regulated, the count of Iba1-positive cells was increased, the expression of CD16, TNF-α and iNOS mRNA was up-regulated ( P<0.05), and no significant change was found in the expression of IL-10, TGF-β1 and CD206 in DNP group ( P>0.05). Compared with DNP group and DNP+ Sham group, the MWT was significantly increased on days 14, 21 and 28 after developing the model, the expression of CGRP and TNF-α in the DRG was down-regulated, the count of Iba1-positive cells was decreased, the expression of CD16, TNF-α and iNOS mRNA was down-regulated, and the expression of IL-10, TGF-β1 and CD206 mRNA was up-regulated in DNP+ SS group ( P<0.05), and no significant change was found in the aforementioned parameters at each time point in DNP and DNP+ Sham groups ( P>0.05). Conclusions:Activation of splenic sympathetic nerve can promote the infiltration and polarization of DRG macrophages, thus participating in the process of diabetic neuropathic pain in mice.

Objective:To evaluate the effect of dexmedetomidine on the viability of dopaminergic neurons in the ventral tegmental area (VTA) of morphine-addicted mice.Methods:Experiment Ⅰ Thirty SPF healthy adult male C57BL/6 mice, aged 8 weeks, weighing 20-25 g, were divided into 3 groups ( n=10 each) using the random number table method: normal saline group (NS group), dexmedetomidine 50 μg/kg group (DEX50 group), and dexmedetomidine 100 μg/kg group (DEX100 group). A morphine addiction model was established by intraperitoneal injection of increasing doses of morphine (10, 20, 30, 40, 50 and 50 mg/kg) for 6 consecutive days in mice. After the successful establishment of the model, dexmedetomidine 50 and 100 μg/kg were intraperitoneally injected for 14 consecutive days in group DEX50 and group DEX100 respectively, while normal saline was given instead in group C. The conditioned place preference (CPP) experiment was conducted every other day. Experiment Ⅱ Thirty SPF healthy adult male C57BL/6 mice, aged 8 weeks, weighing 20-25 g, were divided into 3 groups ( n=10 each) by the random number table method: control group (C group), morphine group (Mor group) and dexmedetomidine 50 μg/kg group (DEX50 group). Normal saline was intraperitoneally injected for 10 consecutive days in group C. Morphine with increasing doses was intraperitoneally injected for 6 days, and then normal saline was intraperitoneally injected for 4 consecutive days in group Mor. Morphine with increasing doses was intraperitoneally injected for 6 days, and then dexmedetomidine 50 μg/kg was intraperitoneally injected for 4 consecutive days in group DEX50. The mice were anesthetized at 90 min after the last intraperitoneal injection, brain tissues were harvested, and the corresponding brain slices of the VTA were selected for c-Fos immunofluorescence staining. Experiment Ⅲ Ten dopamine transporter-Cre recombinase mice were divided into 2 groups ( n=5 each) by the random number table method: morphine group (Mor group) and morphine+ dexmedetomidine 50 μg/kg group (Mor+ DEX group). Stereotaxic viral injection was performed in the brain. rAAV-EF1α-DIO-GCaMP6s was injected into the VTA and an optical fiber was implanted. Three weeks later, a morphine addiction model was established based on Experiment Ⅰ for the CPP experiment, morphine was intraperitoneally injected in group Mor, and morphine and dexmedetomidine were intraperitoneally injected in group Mor+ DEX. The viral fluorescence signals were recorded at 5 min before and 20 min after the drug administration in the three groups. Results:Experiment Ⅰ There was no statistically significant difference in the CPP scores after developing the morphine addiction model among the three groups ( P>0.05). Compared with group NS, the CPP scores were significantly decreased at 4-14 days of the continuous administration in group DEX50 and group DEX100 ( P<0.05). Experiment Ⅱ Compared with group C, the number of c-Fos positive cells in the VTA was significantly increased in group Mor ( P<0.05). Compared with group Mor, the number of c-Fos positive cells in the VTA was significantly decreased in group DEX ( P<0.05). Experiment Ⅲ Compared with that before administration, the calcium signals of dopaminergic neurons in the VTA were significantly enhanced in group Mor ( P<0.05), and no statistically significant difference was found in the calcium signals of dopaminergic neurons in the VTA in group Mor+ DEX ( P>0.05). Compared with group Mor, no statistically significant difference was found in the calcium signals of dopaminergic neurons in the VTA before drug administration ( P>0.05), and the calcium signals of dopaminergic neurons in the VTA were significantly weakened after administration in group Mor+ DEX ( P<0.05). Conclusions:The mechanism by which dexmedetomidine promotes the extinction of morphine addiction is related to the inhibition of the viability of dopaminergic neurons in the VTA of mice.

Objective:To evaluate the role of splenic sympathetic nerve-regulated infiltration and polarization of dorsal root ganglion (DRG) macrophages in diabetic neuropathic pain (DNP) in mice.Methods:Forty-eight specific pathogen-free male C57BL/6 mice, aged 6 weeks, weighing 20-22 g, were divided into 4 groups ( n=12 each) using a random number table method: control group (Con group), DNP group, DNP plus sham operation group (DNP+ Sham group), and diabetes mellitus induced by DNP plus splenic sympathetic denervation group (DNP+ SS group). In DNP+ SS group, the splenic sympathetic denervation procedures were performed using 6-hydroxydopamine solution, while a solvent of 0.2% ascorbic acid saline solution was used as a substitute for 6-hydroxydopamine solution in DNP+ Sham group. After a two-week recovery, the diabetes mellitus was induced by intraperitoneal injection of streptozotocin 120 mg/kg in mice at 8 weeks of age. The mechanical paw withdrawal threshold (MWT) were measured on day 1 before developing the model and on days 7, 14, 21 and 28 after developing the model. After the last behavioral testing, the DRG was taken after anesthesia for determination of the expression of the macrophage marker ionized calcium-binding adaptor molecule 1(Iba1), calcitonin gene-related peptide (CGRP), and tumor necrosis factor-α (TNF-α) (by immunofluorescence) and expression of M1 phenotype markers (CD16, TNF-α, inducible nitric oxide synthase [iNOS]) and M2 phenotype markers (interleukin-10 [IL-10], transforming growth factor-β1 [TGF-β1], and CD206) mRNA (using quantitative real-time polymerase chain reaction). Results:Compared with Con group, the MWT was significantly decreased on days 14, 21 and 28 after developing the model, the expression of CGRP and TNF-α in the DRG was up-regulated, the count of Iba1-positive cells was increased, the expression of CD16, TNF-α and iNOS mRNA was up-regulated ( P<0.05), and no significant change was found in the expression of IL-10, TGF-β1 and CD206 in DNP group ( P>0.05). Compared with DNP group and DNP+ Sham group, the MWT was significantly increased on days 14, 21 and 28 after developing the model, the expression of CGRP and TNF-α in the DRG was down-regulated, the count of Iba1-positive cells was decreased, the expression of CD16, TNF-α and iNOS mRNA was down-regulated, and the expression of IL-10, TGF-β1 and CD206 mRNA was up-regulated in DNP+ SS group ( P<0.05), and no significant change was found in the aforementioned parameters at each time point in DNP and DNP+ Sham groups ( P>0.05). Conclusions:Activation of splenic sympathetic nerve can promote the infiltration and polarization of DRG macrophages, thus participating in the process of diabetic neuropathic pain in mice.

Objective:To evaluate the effect of dexmedetomidine on the viability of dopaminergic neurons in the ventral tegmental area (VTA) of morphine-addicted mice.Methods:Experiment Ⅰ Thirty SPF healthy adult male C57BL/6 mice, aged 8 weeks, weighing 20-25 g, were divided into 3 groups ( n=10 each) using the random number table method: normal saline group (NS group), dexmedetomidine 50 μg/kg group (DEX50 group), and dexmedetomidine 100 μg/kg group (DEX100 group). A morphine addiction model was established by intraperitoneal injection of increasing doses of morphine (10, 20, 30, 40, 50 and 50 mg/kg) for 6 consecutive days in mice. After the successful establishment of the model, dexmedetomidine 50 and 100 μg/kg were intraperitoneally injected for 14 consecutive days in group DEX50 and group DEX100 respectively, while normal saline was given instead in group C. The conditioned place preference (CPP) experiment was conducted every other day. Experiment Ⅱ Thirty SPF healthy adult male C57BL/6 mice, aged 8 weeks, weighing 20-25 g, were divided into 3 groups ( n=10 each) by the random number table method: control group (C group), morphine group (Mor group) and dexmedetomidine 50 μg/kg group (DEX50 group). Normal saline was intraperitoneally injected for 10 consecutive days in group C. Morphine with increasing doses was intraperitoneally injected for 6 days, and then normal saline was intraperitoneally injected for 4 consecutive days in group Mor. Morphine with increasing doses was intraperitoneally injected for 6 days, and then dexmedetomidine 50 μg/kg was intraperitoneally injected for 4 consecutive days in group DEX50. The mice were anesthetized at 90 min after the last intraperitoneal injection, brain tissues were harvested, and the corresponding brain slices of the VTA were selected for c-Fos immunofluorescence staining. Experiment Ⅲ Ten dopamine transporter-Cre recombinase mice were divided into 2 groups ( n=5 each) by the random number table method: morphine group (Mor group) and morphine+ dexmedetomidine 50 μg/kg group (Mor+ DEX group). Stereotaxic viral injection was performed in the brain. rAAV-EF1α-DIO-GCaMP6s was injected into the VTA and an optical fiber was implanted. Three weeks later, a morphine addiction model was established based on Experiment Ⅰ for the CPP experiment, morphine was intraperitoneally injected in group Mor, and morphine and dexmedetomidine were intraperitoneally injected in group Mor+ DEX. The viral fluorescence signals were recorded at 5 min before and 20 min after the drug administration in the three groups. Results:Experiment Ⅰ There was no statistically significant difference in the CPP scores after developing the morphine addiction model among the three groups ( P>0.05). Compared with group NS, the CPP scores were significantly decreased at 4-14 days of the continuous administration in group DEX50 and group DEX100 ( P<0.05). Experiment Ⅱ Compared with group C, the number of c-Fos positive cells in the VTA was significantly increased in group Mor ( P<0.05). Compared with group Mor, the number of c-Fos positive cells in the VTA was significantly decreased in group DEX ( P<0.05). Experiment Ⅲ Compared with that before administration, the calcium signals of dopaminergic neurons in the VTA were significantly enhanced in group Mor ( P<0.05), and no statistically significant difference was found in the calcium signals of dopaminergic neurons in the VTA in group Mor+ DEX ( P>0.05). Compared with group Mor, no statistically significant difference was found in the calcium signals of dopaminergic neurons in the VTA before drug administration ( P>0.05), and the calcium signals of dopaminergic neurons in the VTA were significantly weakened after administration in group Mor+ DEX ( P<0.05). Conclusions:The mechanism by which dexmedetomidine promotes the extinction of morphine addiction is related to the inhibition of the viability of dopaminergic neurons in the VTA of mice.

Objective:To evaluate the role of spinal cord neuron Src-associated-in-mitosis-68-kDa (SAM68)-transient receptor potential vanilloid-1 channel (TRPV1) signaling pathway in diabetic neuropathic pain (DNP) in mice.Methods:Forty SPF male C57BL/6 mice, aged 8 weeks, weighing 18-22 g, were used in this study. Diabetes mellitus was induced by intraperitoneal streptozotocin 0.12 mg/g, and successful DNP model was defined as decrease in the mechanical paw withdrawal threshold (MWT) of the hind limb≥50% of the baseline value. Twenty-four mice with DNP at 4 weeks after developing the model were divided into 3 groups ( n=8 each) using a simple random sampling: DNP group, SAM68 knocked down group (KD group) and virus control group (VC group). Eight diabetic mice with decrease in MWT <50% were randomly selected as non-DNP group (ND group), and 8 normal mice were randomly selected as control group (NC group). At 4 weeks after developing the diabetes mellitus model, SAM68 gene silencing virus and empty virus were injected into the lumbar enlargement of the spinal cord in KD group and VC group, respectively. MWT was measured before developing the diabetes mellitus model and at 4 and 6 weeks after developing the diabetes mellitus model. The mice were sacrificed after the end of MWT measurement at week 6 after developing the model, spinal cord tissues were collected and the expression of SAM68 and TRPV1 was detected by Western blot, and their localization in the spinal cord was observed by immunofluorescence. Results:Compared with NC and ND groups, the MWT was significantly decreased at 4 and 6 weeks after developing the model, and the expression of SAM68 and TRPV1 in spinal cord tissues was up-regulated in DNP group ( P<0.05). Compared with DNP group, the MWT was significantly increased at 6 weeks after developing the model, the expression of SAM68 and TRPV1 in spinal cord tissues was down-regulated, and no significant change was found in the parameters mentioned above in VC group ( P>0.05). SAM68 and TRPV1 were expressed in neurons in the same region of the spinal cord. Conclusions:Activation of SAM68-TRPV1 signaling pathway in spinal cord neurons is involved in the pathophysiological mechanism of DNP in mice.

Objective:To evaluate the role of lactate-induced mitochondrial division of spinal cord neurons in diabetic neuropathic pain (DNP) in mice.Methods:Thirty-six SPF-grade healthy adult male C57BL/6 mice, aged 2 months, weighing 20-25 g, were divided into 3 groups ( n=12 each) using a random number table method: control group (CON group), DNP group, and DNP+ sodium oxalate group (OXA group). The diabetic model was established by intraperitoneal injection of streptozotocin 130 mg/kg. After the diabetic model was successfully established, sodium oxalate 750 mg/kg was intraperitoneally injected once a day for 4 consecutive weeks to inhibit lactate production in OXA group, while the equal volume of normal saline was given instead at the same time in C group and DNP group. The mechanical paw withdrawal threshold (MWT) of the left hindpaw was measured before developing the model and at 1, 2, 3 and 4 weeks after developing the model. After completing the last behavioral testing, the spinal cord tissue of the lumbar segment (L 4-6) was taken for determination of the levels of lactate in serum and spinal cord tissues (by the colorimetric method), expression of the mitochondrial membrane potential, reactive oxygen species (ROS) content (using JC-1 or DHE probes), expression of mitochondrial dynamin-related protein 1 (Drp1) and mitochondrial protein mitofusin 2 (Mfn2) (by Western blot), and co-expression of Drp1 and neuronal neuronal marker neuronal nuclear protein (NeuN) (by immunofluorescence double labeling) and for examination of the structure and the number of mitochondria (with a transmission electron microscope). Results:Compared with C group, the MWT was significantly decreased after developing the model, the levels of lactate in serum and spinal cord tissues and ROS content in the spinal cord were increased, the mitochondrial membrane potential was decreased, the Drp1 expression was up-regulated, the Mfn2 expression was down-regulated, the number of mitochondria was increased, the area was reduced ( P<0.05), and the co-expression of Drp 1 and NeuN was increased in DNP group and OXA group. Compared with DNP group, the MWT was significantly increased after developing the model, the levels of lactate in serum and spinal cord tissues and ROS content in the spinal cord were decreased, the mitochondrial membrane potential was increased, the Drp1 expression was down-regulated, the Mfn2 expression was up-regulated, the number of mitochondria was decreased, the area was increased ( P<0.05), and the co-expression of Drp 1 and NeuN was decreased in OXA group. Conclusions:Lactate-induced excessive mitochondrial division of spinal cord neurons can lead to mitochondrial dysfunction, which may be involved in the maintenance mechanism of DNP in mice.

Objective:To evaluate the effect of intrathecal insulin-like growth factor-1 (IGF-1) on chemotherapy-induced neuropathic pain (NP) in mice.Methods:Forty clean-grade healthy male C57 mice, aged 7-9 weeks, weighing 22-24 g, were divided into 4 groups ( n=10 each) using a random number table method: control group (group C), chemotherapy-induced NP group (group CIPN), low-dose IGF-1 group (group I1) and high-dose IGF-1 group (group I2). In CIPN, I1 and I2 groups, oxaliplatin 5 mg/kg was intraperitoneally injected for 5 consecutive days to establish chemotherapy-induced NP model.Normal saline 0.2 ml was given in group C. After measurement of the pain threshold at 10 days after establishment of the model, IGF-1 0.5 and 1.0 μg were intrathecally injected in group I1 and group I2, respectively.Normal saline 5 μl was intrathecally injected in C and CINP groups.Mechanical withdrawal threshold (MWT) was measured at 3, 5, 8, 10, 11, 13 and 15 days after establishment of the model.After measurement of the pain threshold at 15 days after establishment of the model, the expression of spinal IGF-1, IGF-1receptor (IGF-1R), interleukin (IL)-17A, IL-1β and tumor necrosis factor (TNF)-α was detected, and IGF-1 positive cells were counted using immunofluorescence. Results:Compared with group C, MWT was significantly decreased, the expression of spinal IGF-1 was down-regulated, the count of IGF-1 positive cells was decreased, and expression of IL-17A, IL-1β and TNF-α was up-regulated at 3-25 days after establishment of the model in CINP, I1 and I2 groups ( P<0.05). Compared with group CIPN, MWT was significantly increased at 15 days after establishment of the model in group I1, and MWT was increased, the expression of spinal IGF-1 was up-regulated, the count of IGF-1 positive cells was increased, and expression of IL-17A, IL-1β and TNF-α was down-regulated at 13 and 15 days after establishment of the model in group I2 ( P<0.05). Compared with group I1, the count of IGF-1 positive cells in spinal dorsal horn was increased in group I2 ( P<0.05). There was no significant difference in the expression of spinal IGF-1R among the 4 groups ( P>0.05). Conclusion:Intrathecal IGF-1 can alleviate chemotherapy-induced NP, and the mechanism may be related to inhibiting the inflammatory responses in spinal cord of mice.

Objective To evaluate the role of spinal cord tumor necrosis factor receptor-associated factor 6 (TRAF6)/nuclear factor kappa B (NF-κB)signaling pathway in the development of diabetic neuropathic pain (DNP)in rats.Methods Clean-grade healthy adult male Sprague-Dawley rats,aged 2 months,weighing 180-230 g,in which IT catheters were implanted,were used in this study.Streptozotocin 60 mg/kg was intraperitoneally injected after IT catheterization to establish the model of DNP.Twelve DNP rats were divided into 2 groups (n =6 each) by a random number table method:DNP group and DNP plus TRAF6 inhibitor group (group DTR).Another 6 age-matched Sprague-Dawley rats were used as normal control group (group NC).The rats in group DC and group DTR received IT injection of dimethyl sulfoxide 10 μl and TRAF6 inhibition 10 μg,respectively,once a day for 7 consecutive days starting from day 21 after establishing the model.The mechanical paw withdrawal threshold (MWT) was determined before establishing the model (T1),on 7,14 and 21 days after establishing the model (T2-4),and on 1,4 and 7 days after IT injection (T5-7).The rats were sacrificed after the last MWT measurement,and the L3-5 segments of the spinal cord were removed for determination of the expression of TRAF6 and NFκB p65 by Western blot.Results Compared with group NC,the MWT at T3-7 in group DC and at T3-6 in group DTR was significantly decreased,and the expression of spinal TRAF6 and NF-κB p65 was up-regulated in DC and DTR groups (P＜0.05).Compared with group DC,the MWT was significantly increased at T6-7,and the expression of spinal TRAF6 and NF-κB p65 was down-regulated in group DTR (P ＜ 0.05).Conclusion Spinal cord TRAF6/NF-κB signaling pathway is involved in the development of DNP in rats.

Objective To evaluate the effect of pulsed radiofrequency (PRF) on the phenotypic transformation of the lumbar sympathetic ganglion (LSG) in the rats with diabetic neuropathic pain (PDN).Methods Twenty-four clean-grade healthy adult male Sprague-Dawley rats,aged 2 months,weighing 180-220 g,were divided into 4 groups (n =6 each) according to the method of random number table:control group (group C),group PDN,group PRF,and PRF control group (group PC).The PDN model was established by intraperitoneal injection of streptozotocin 60 mg/kg in anesthetized rats.Citrate-sodium citrate buffer 6 ml/kg was intraperitoneally injected in group C.Group PC only received radiofrequency needle puncture.PRF was performed on the right L3 LSG in group PRF.The mechanical paw withdrawal threshold (MWT) to yon Frey filament stimulation was measured before intraperitoneal injection (baseline,T0),before PRF and at 1,3,5,7 and 14 days after PRF.The rats were then sacrificed,and ipsilateral L3 LSGs were removed for determination of the expression of tyrosine hydroxylase (TH) and vesicle glutamate transporter2 (VGLUT2) in LSGs (by double immunofluorescent staining) and for examination of pathological changes (with a light microscope).The number of neurons expressing VGLUT2 was counted.Results Compared with group C,the MWT was significantly decreased at T1-6,and the number of neurons expressing VGLUT2 was increased at T6 in PDN,PC and PRF groups (P＜0.05).Compared with PDN and PC groups,the MWT was significantly increased at T2-6,and the number of neurons expressing VGLUT2 was decreased at T6 in group PRF (P＜0.05).TH expression in LSGs was found,and no VGLUT2 expression in LSGs was observed in group C,the expression of TH and VGLUT2 in LSGs was found in the other three groups,especially in PDN and PC groups,and most of the neurons expressing VGLUT2 expressed TH simultaneously.Conclusion The mechanism by which PRF mitigates PDN is related to inhibiting the phenotypic transformation of LSGs in the rats.

Objective To evaluate the effect of intrathecal cardamonin on diabetic neuropathic pain (DNP) in rats.Methods Healthy adult male Sprague-Dawley rats,aged 2 months,weighing 180-220 g,were included in the study.Diabetes mellitus was produced by intraperitoneal injection of streptozotocin 60 mg/kg after intrathecal catheterization.When decrease in pain threshold＞50％ of the baseline at 21 days after diabetes mellitus was produced,the induction of DNP was considered successful.Twenty-four rats with DNP were divided into 4 groups (n=6 each) using a random number table:group DNP,rapamycin group (group R),cardamonin 50 μg group (group D50) and cardamonin 100 μg group (group D100).Another 6 healthy age-matched rats were used as normal control (group C).In DNP,R,D50 and D100 groups,dimethyl sulfoxide 10 μl,rapamycin 5 μg and cardamonin 50 μg and 100 μg were intrathecally injected,respectively,once a day for 7 consecutive days starting from 21 days after successful estabiishment of the model.Mechanical paw withdrawal threshold (MWT) was measured before establishment of the model,on 7,14 and 21 days after establishment of the model,and on 1,4 and 7 days after intrathecal injection.The rats were sacrificed after the last MWT measurement,and their L3-5 segments of the spinal cord were removed for determination of the expression of S6K,p-S6K and synapsin Ⅱ by Western blot.Results Compared with group C,MWT was significantly decreased,and the expression of spinal S6K,p-S6K and synapsin Ⅱ was up-regulated in group DNP (P＜0.05 or 0.01).Compared with group DNP,MWT was significantly increased,and the expression of spinal S6K,p-S6K and synapsin Ⅱ was down-regulated in R,D50 and D100 groups (P＜0.05 or 0.01).Compared with group D50,MWT was significantly increased,and the expression of spinal S6K,p-S6K and synapsin Ⅱ was down-regulated in group D100 (P＜0.05).Conclusion Intrathecal cardamonin can relieve DNP in rats,and the mechanism is related to inhibiting spinal mammalian target of rapamycin activity and down-regulating the expression of synapsin Ⅱ.