The effect of spinal interleutkin-33 on radicular pain after non-compressive lumbar disc herniation / 中华物理医学与康复杂志

Objective:To explore the effect of spinal interleutkin-33 (IL-33) on radicular pain in rats modeling non-compressive lumbar disc herniation.Methods:A total of 80 male Sprague-Dawley rats were randomly divided into a sham operation group, a model group, a lentivirus negative control group, a low-dose IL-33 recombinant lentivirus group and a high-dose IL-33 group, each of 16. Non-compressive lumbar disc herniation was successfully induced in all except the rats in the sham operation group. Two days later, the model group was injected intrathecally with 10μl of enhanced infection solution. The lentivirus control group received 10μl of negative lentivirus, the low-dose IL-33 recombinant lentivirus group received 5μl of IL-33 recombinant lentivirus and the high-dose IL-33 recombinant lentivirus group received 10μl of IL-33 recombinant lentivirus. The 50% paw withdrawal threshold (50% PWT) was measured one day before the modeling and on the 1 st, 3 rd, 5 th, 7 th, 9 th, 11 th, 13 th, 15 th, 17 th, 19 th, and 21 st day afterward. On the 12 th day the expressions of IL-33 protein and mRNA were evaluated. Results:The average expression of IL-33 protein and mRNA in the model and the lentivirus negative control group increased significantly after the modelling compared with the sham group, while expression in the low- and high-dose IL-33 recombinant lentivirus groups was significantly lower than in the lentivirus negative control group. Compared with one day before the modelling, average 50% PWTs on the affected side decreased significantly in all of the modelling groups. From the 9 th to the 21 st day significantly increased 50% PWTs were observed on the affected side in the low-dose and high-dose IL-33 recombinant lentivirus groups compared with the other two modelling groups. Immunostaining showed significant increase in the expression of IL-33 in the dorsal horn of the spinal cord in the model group, compared with the sham operation group. Significant decrease in the average expression of IL-33 in the spinal dorsal horns was observed in the low-dose and high-dose IL-33 recombinant lentivirus groups. Conclusions:Intervertebral disk herniation may increase the expression of IL-33 in the spinal cord, and may cause radicular pain.

Role of spinal P2X4 receptor in remifentanil-induced postoperative hyperalgesia / 中南大学学报(医学版)

To explore the role of P2X4 receptor in opioid-induced hyperalgesia (OIH).
 Methods: A total of 30 Sprague-Dawley (SD) male rats were randomly divided into 5 groups: a saline (N0) group, a remifentanil at 0.5 μg/(kg.min) (R1) group, a remifentanil at 1.0 μg/(kg.min) (R2) group, a remifentanil at 1.5 μg/(kg.min) (R3) group, and a remifentanil at 5.0 μg/(kg.min) (R4) group. The paw withdrawal mechanical threshold (PWMT) and paw withdrawal thermal latency (PWTL) were measured at follow time points to optimize the dosages: the day before treatment (T1), 30 min after tail intravenous catheterization (T2), and 30 min (T3), 1 h (T4), 2 h (T5), 24 h (T6) after withdrawal from remifentanil. Then, the rats were randomly divided into 2 groups: a saline group (N group), a remifentanil at 1.0 μg/(kg.min) group (R group). The PWMT and PWTL were measured at follow time points: T1, T2, and T4. The lumbar enlargement of spine was selected at 1 h after withdrawal from remifentanil, and the expression of P2X4 receptor mRNA and protein was examined in OIH. Additional male rats were selected and randomly divided into 2 groups: a plantar incision surgery followed by saline treatment group (I+N group), a plantar incision surgery followed by remifentanil treatment group (I+R group). The PWMT and PWTL were measured at follow time points: T1, T2, T3, T4, T5, T6, 48 h (T7) and 72 h (T8) after withdrawal from remifentanil. The lumbar enlargement of spine was selected at 1 h after withdrawal from remifentanil, the expression of P2X4 receptor mRNA and protein was examined by PCR and Western blotting, and the microglial activation in spine 1 h after withdrawal from remifentanil were assessed by immunofluorescence.
 Results: The pain thresholds including PWMT and PWTL in different groups were as follows: R4 group

Role of DNA methyltransferases in the pathogenesis of neuropathic pain in rats / 中南大学学报(医学版)

OBJECTIVE@#To explore the role of DNA methyltransferases (DNMTs) in the pathogenesis of neuropathic pain (NPP) in rats following sciatic nerve chronic constriction injury (CCI).
@*METHODS@#A total of 27 adult male Sprague-Dawley rats with successful implantation of lumbar intrathecal catheter were randomly divided into 3 groups: a sham + normal saline group (sham+NS group), a CCI+NS group, and a CCI+5-azacytidine group (CCI+5-AZA group) (n=9 in each group). The rats in the Sham+NS group and the CCI+NS group received NS, while the rats in the CCI+5-AZA group received 10 μmol/L of 5-AZA (a DNMTs inhibition) once a day through spinal injection from the 3th day to 14th day after CCI surgery. Mechanical withdrawal threshold (MWT) and thermal withdrawal latency (TWL) of ipsilateral hinds in the 3 groups were measured before or at the 3th, 5th, 7th, 10th or 14th day after CCI surgery. At the end of experiments, all rats were killed under deep anesthesia and their lumbar spinal cords were dissected to examine the DNMT1, DNMT3a and DNMT3b expression by RT-PCR, Western blot and immunohistochemistry, respectively.
@*RESULTS@#Compared with the sham+NS group, the MWT and TWL in the CCI+NS group were obviously reduced from the 3th day to the 14th day after surgery (both P<0.05). Compared with the CCI+NS group, the MWT and TWL in the CCI+5-AZA group were obviously increased from the 5th day to the 14th day after surgery (both P<0.05), but they were still reduced compared with the sham+NS group (both P<0.05). The DNMT1, DNMT3a and DNMT3b were highly expressed in the lumbar spinal dorsal horn in all rats, and the positive signals were mainly located in the nucleus. The DNMT1, DNMT3a and DNMT3b levels in the CCI+NS group were increased significantly compared with that in the sham+NS group on the 14th day after surgery (all P<0.05). The DNMT1, DNMT3a and DNMT3b expressions in the CCI+ 5-AZA group were decreased significantly compared with that in the CCI+NS group (all P<0.05), but they still increased compared with that in the sham+NS group (all P<0.05). 
@*CONCLUSION@#Up-regulation of DNMTs in the lumbar spinal may play an important role in the pathogenesis of NPP in CCI rats. DNMTs inhibitors (5-AZA) could reduce expression of DNMTs and attenuate CCI-induced NPP, which might be a potential therapeutic drug for NPP.

Effects of maternal behaviors in rats with neuropathic pain on emotions of offspring rats and the relationship with DNA methylation in amygdala / 中华麻醉学杂志

Objective To investigate the effects of maternal behaviors in the rats with neuropathic pain (NP) on emotions of offspring rats and the relationship with DNA methylation in the amygdala.Methods Forty-eight healthy adult Sprague-Dawley rats (24 males and 24 females),weighing 200-250 g,were used in the study.Twelve female and 12 male rats were randomly selected,and NP was induced by chronic constriction injury (CCI).Each female rat was mated with one male rat at 10 days after CCI.Fortyeight F1 generation rats of maternal rats with NP were randomly divided into 2 groups (n =24 each) using a random number table:NP1 group and NP2 group.Forty-eight F1 generation rats of normal maternal rats were randomly divided into 2 groups (n=24 each) using a random number table:S1 group and S2 group.The F1 generation rats were cross-fed immediately after birth between group NP2 and group S2,and fed by their own mother rats in NP1 and S1 groups.All the offspring rats were fed to 21 days after birth by the maternal rats selected,and separately fed to 30 days after birth,and then subjected to behavioral testing.Retrieving and licking pups were recorded after delivery in maternal rats to evaluate the maternal behaviors.The mechanical and thermal paw withdrawal thresholds were measured in the offspring rats.Elevated plus maze and open field tests were conducted to detect anxiety and depression behaviors in the offspring rats.At 1 day after completion of behavioral testing,the expression of DNA methyltransferase 1 (DNMT1) and DNA methyltransferase 3a and 3b in the amygdala was detected by Western blot analysis.Results Compared with S1 or S2 groups,the latency to lick pups,latency to retrieve pups,and total retrieval time were significantly prolonged,and the total time spent licking pups was significantly shortened in NP1 group or NP2 group (P＜0.05 or 0.01).There was no significant difference in the mechanical and thermal paw withdrawal thresholds in the offspring rats between the four groups (P＞0.05).Compared with group S1,the ratios of time spent in the open arm to the closed arm and of time spent in the central square to the peripheral square were significantly decreased,DNMT1 expression in the amygdala was significantly up-regulated,and the total DNA methylation was increased in the offspring rats in S2 and NP1 groups (P＜0.05).Compared with group NP2,the ratios of time spent in the open arm to the closed arm and of time spent in the central square to the peripheral square were significantly decreased,DNMT1 expression in the amygdala was significantly up-regulated,and the total DNA methylation was increased in the offspring rats in S2 and NP1 groups (P＜0.05).Conclusion Decreased maternal behaviors in the rats with NP results in negative emotions including anxiety and depression in the offspring rats,and the mechanism is related to increased DNA methylation in the amygdala of the offspring rats.

The expressions of IL-33 and ST2 receptor in nervous system and their roles in pain / 中国医师杂志

Interleukin-33 (IL-33),a novel member of IL-1 family,is a multifunctional cytokine.IL-33 can act as a transcriptional repressor.It can also bind to growth stimulation expressed gene 2 protein (ST2) to induce the activation of some inflammatory cells.IL-33 is extensively expressed in nervous system.Some studies showed that the levels of IL-33 and ST2 were significantly changed in pain.Some reports demonstrated that the IL-33/ST2 signaling pathway played critical roles in them.This present article will review the biological characteristics of IL-33/ST2 and their expressions in nervous system and significance of interventional pain related diseases.

Role of hippocampal histone acetylation in isoflurane-induced amnestic effect in mice / 中华麻醉学杂志

Objective To evaluate the role of hippocampal histone acetylation in isoflurane-induced amnestic effect in mice.Methods Fifty-four male C57BL/6J mice,aged 8 weeks,weighing 18-22 g,were randomly divided into 3 groups (n =18 each) using a random number table:control group (group C),isoflurane group (group ISO) and histone deacetylase inhibitor sodium butyrate group (group SB).Group C inhaled 35％ oxygen for 30 ain,and ISO and SB groups inhaled the mixture of 35 ％ oxygen and 0.4％ isoflurane for 30 min,and then the animals underwent contextual fear conditioning training.After the end of training,normal saline 6 ml/kg was intraperitoneally injected in C and ISO groups,while in group SB,sodium butyrate 1.2 g/kg was intraperitoneally injected.One hour after the end of training,3 mice were sacrificed randomly in each group and their hippocampi were immediately removed for determination of the expression of acetylated histone-H3 (Ac-H3) and Ac-H4 by Western blot.Twenty-four hours after the end of training,contextual fear conditioning test and open field test were conducted.The freezing time,total distance and time of staying at the central zone were recorded.Results Compared with group C,Ac-H3 and Ac-H4 expression was significantly down-regulated,and the percentage of freezing time during testing was decreased in group ISO (P ＜ 0.05).Compared with group ISO,Ac-H3 and Ac-H4 expression was significantly up-regulated,and the percentage of freezing time during testing was increased in group SB (P ＜ 0.05).There was no significant difference in the percentage of freezing time during training,total distance and time of staying in the central zone among the 3 groups (P ＞ 0.05).Conclusion Hippocampal histone acetylation is involved in the regulation of isoflurane-induced amnestic effect in mice.

Effects of different degrees of neuromuscular blockade induced by rocuronium on facial nerve evoked-electromyographic monitoring in patients undergoing resection of acoustic neuroma / 中华麻醉学杂志

Objective To investigate the effects of different degrees of neuromuscular blockade (NMB) induced by rocuronium on facial nerve evoked-electromyographic (EEMG) monitoring in patients undergoing resection of acoustic neuroma.Methods Thirty-five ASA Ⅰ or Ⅱ patients of both sexes,aged 20-64 yr,with body mass index ≤30 kg/m2,scheduled for elective resection of acoustic neuroma under general anesthesia,were included in the study.Anesthesia was induced with midazolam,fentanyl and propofol.The patients were mechanically ventilated after tracheal intubation.Facial nerve EEMG monitoring and peripheral NMB monitoring were performed simultaneously during operation.Facial nerve EEMG was monitored using the Epoch XP2000 multichannel electrophysiological nerve monitoring system (Axon Co.,USA),facial nerve was stimulated and evoked potential of orbicularis oculi was recorded during operation.Peripheral NMB degrees were monitored with TOF-Watch SX monitor (Organon Co.Holland).After rocuronium 0.6 mg/kg was injected intravenously,the facial nerve EEMG responses were monitored when the degree of NMB (T1) was at 100％,75％,50％,25％ and 0 of the control height.The amplitude and latency of EEMG were recorded.The amplitude reservation ratio (the ratio of the amplitude of EEMG monitored to the baseline value) was calculated.Linear correlation of the amplitude reservation ratio or latency of EEMG with the degree of NMB was analyzed.Results No EEMG response was elicited when the degree of NMB was 100％ in 6 patients.The lirear regression equation of the interaction between the degree of NMB (X) and the amplitude reservation ratio (Y) was Y =1 - 0.787 X,the coefficient of determination was 0.898 ( P ＜ 0.05) and the correlation coefficient was - 0.947 ( P ＜ 0.05).The correlation coefficient between the latency of EEMG and the degree of NMB was 0.328 ( P ＜ 0.05).Conclusion When the degree of NMB is maintained at 25 ％-50％,facial nerve EEMG can be monitored effectively and body movement can be avoided during resection of acoustic neuroma.

Role of cyclooxygenases in up-regulation of P2X3 receptor expression in dorsal root ganglion in rats with neuropathic pain / 中华麻醉学杂志

Objective To investigate the role of cyclooxygenases (COXs) in the up-regulation of the expression of P2X3 receptors in the dorsal root ganglion (DRG) in rats with neuropsthic pain. Methods Twenty-four male SD rats, weighing 250-280 g, were randomly divided into 4 groups ( n = 6 each): sham operation group (group S), chronic constrictive injury (CCI) group, COX-1 inhibitor ibuprofen group (group Ⅰ), and COX-2 inhibitor celecoxib group (group C). Neuropathic pain was induced by CCI. The animals were anesthetized with intraperitoneal 10% chloral hydrate 300-500 mg/kg. CCI was produced by placing 4 ligatures on the left sciatic nerve at 1 mm intervals. In group S, the left sciatic nerve was only exposed but not ligated. In groups Ⅰ and C, ibuprofen 40 mg·kg-1 ·d-1 and celecoxib 30 mg·kg-1 ·d-1 were given through a gastric tube into the stomach at day 3-14 after operation respectively. Paw withdrawal latency (PWL) and paw withdrawal threshold (PWT) were measured before operation (baseline), and at 3, 5, 7, 10 and 14 days after operation. Then the rats were sacrificed and their L()-6 DRGs were removed to detect the expression of P2X3 mRNA and protein. Results Compared with group S, PWL was significantly shortened, PWT decreased, and P2X3 mRNA and protein expression up-regulated in group CCI ( P ＜ 0.05＝. Compared with group CCI, PWL was significantly prolonged, PWT increased, and P2X3 mRNA and protein expression down-regulated in groups Ⅰ and C (P ＜0.05＝. Compared with group Ⅰ, PWL was significantly prolonged, PWT increased, and P2X3 mRNA and protein expression up-regulated in group C ( P ＜0.05＝. Conclusion COXs are involved in the up-regulation of the expression of P2X3 receptors in the DRG in rats with neuropathic pain, and the effect of COX-1 is stronger than that of COX-2.