Effect of hydrogen on cell pyroptosis during lung injury in severely burned rats / 中华麻醉学杂志

Objective:To evaluate the effect of hydrogen on cell pyroptosis during lung injury in severely burned rats.Methods:Forty-eight clean-grade healthy adult male Sprague-Dawley rats, weighing 200-230 g, aged 6-7 weeks, were divided into 4 groups ( n=12 each) by the random number table method: sham operation group (SH group), sham operation+ hydrogen group (SH+ H 2 group), burn group (B group) and burn+ hydrogen group (B+ H 2 group). In group B and group B+ H 2, the Ⅲ degree burn model of the back (about 40% of the total body surface area) was prepared in anesthetized animals. The back was shaved and then subjected to a perm at skin temperature in group SH and group SH+ H 2. Rats were exposed to 2% hydrogen for 1 h starting from 1 and 6 h after burn in SH+ H 2 group and B+ H 2 group, respectively. At 12 and 24 h after burn, the rats were sacrificed and lung tissues were obtained for examination of pathological changes which were scored and for determination of the contents of interleukin-1beta (IL-1β) and IL-18 in lung tissues (by enzyme-linked immunosorbent assay) and expression of NOD-like receptor thermal protein domain associated protein 3 (NLRP3), caspase-1 and Gasdermin D protein (GSDMD) in lung tissues (by Western blot). Results:Compared with SH group, the pathological scores were significantly increased at 12 and 24 h after burn in group B ( P<0.05). The pathological scores were significantly decreased at 12 and 24 h after burn in group B+ H 2 as compared with group B ( P<0.05). Compared with SH group, the contents of IL-1β and IL-18 in lung tissues were significantly increased at 12 and 24 h after burn, and the expression of NLRP3, caspase-1 and GSDMD was up-regulated in B and B+ H 2 groups ( P<0.05). Compared with group B, the contents of IL-1β and IL-18 in lung tissues were significantly decreased at 12 and 24 h after burn, and the expression of NLRP3, caspase-1 and GSDMD was down-regulated in group B+ H 2 ( P<0.05). Conclusions:The mechanism by which hydrogen attenuates lung injury may be related to inhibition of cell pyroptosis in severely burned rats.

Effect of gender on anesthetic potency of ciprofol for gastroscopy when combined with fentanyl / 中华麻醉学杂志

Objective:To evaluate the effect of gender on anesthetic potency of ciprofol for gastroscopy when combined with fentanyl.Methods:American Society of Anesthesiologists Physical Status classification Ⅰ or Ⅱ patients, aged 18-50 yr, with body mass index of 18-25 kg/m 2, undergoing elective gastroscopy with intravenous anesthesia, were divided into 2 groups according to gender: male group (M group) and female group (F group). After fentanyl 1.5 μg/kg was intravenously injected, ciprofol was given by the Dixon′s up-and-down method, with the initial dose of 0.4 mg/kg followed by dose increment/decrement of 0.04 mg/kg. The ED 50 and 95% confidence interval of ciprofol for gastroscopy anesthesia were calculated by the probit regression analysis. Results:The ED 50 (95% confidence interval) of ciprofol for gastroscopy was 0.33 (0.32-0.34) mg/kg in F group and 0.27 (0.26-0.28) mg/kg in M patients when combined with fentanyl 1.5 μg/kg. There was no significant difference between the two groups ( P>0.05). Conclusions:There is no significant gender difference in the anesthetic potency of ciprofol for gastroscopy (ED 50: female 0.33 mg/kg, male 0.27 mg/kg) when combined with fentanyl (1.5 μg/kg).

Effect of sleep fragmentation on postoperative cognitive dysfunction and hippocampal glutamatergic metabolism in aged mice anesthetized with isoflurane / 中华麻醉学杂志

Objective:To evaluate the effect of sleep fragmentation on postoperative cognitive dysfunction (POCD) and hippocampal glutaminergic metabolism in aged mice anesthetized with isoflurane.Methods:Forty healthy SPF-grade male C57BL/6J mice, aged 18 months, weighing 20-30 g, were divided into 4 groups ( n= 10 each) by the random number table method: normal control group (group C), sleep fragmentation group (group SF), isoflurane anesthesia/surgery group (group I/S), and sleep fragmentation plus isoflurane anesthesia/surgery group (group SF+ I/S). Group C did not received any treatment. Group SF received sleep fragmentation for 24 h. The right carotid artery exposure was performed under isoflurane anesthesia in group I/S. Group SF+ I/S received isoflurane anesthesia/right carotid artery exposure at 24 h after sleep fragmentation. The metabolic levels of glutamate (Glu), glutamine (Gln), Glu/Gln complex (Glx), and N-acetylaspartate (NAA) and their ratio to creatine (Cr) were measured by in vivo 9.4T hydrogen proton magnetic resonance spectroscopy at 2 h after anaesthesia. Y maze and Morris water maze tests were used to evaluate the cognitive function at 1-7 days after surgery. The mice were sacrificed after the behavioral testing, brain tissues were immediately obtained, and the number of Nissl bodies and density of dendritic spines in the hippocampal CA1 region were measured by Nissl staining and Golgi staining, respectively. Results:Compared with group C, the percentage of exploration time and shuttle times at the novel arm were significantly decreased, the number of crossing the original platform was decreased, the time of stay at the target quadrant was shortened, the ratios of Glu/Cr, Gln/Cr and Glx/Cr in the hippocampal CA1 region were increased, and the ratio of NAA/Cr was decreased, and the number of Nissl bodies and density of dendritic spines were decreased in SF, I/S and SF+ I/S groups ( P<0.05). Compared with group SF and group I/S, the percentage of exploration time and shuttle times at the novel arm were significantly decreased, the number of crossing the original platform was decreased, the time of stay at the target quadrant was shortened, the ratios of Glu/Cr and Glx/Cr in hippocampal CA1 region was increased, the ratio of NAA/Cr was decreased, and the number of Nissl bodies and density of dendritic spines were decreased in group SF+ I/S ( P<0.05). Conclusions:Sleep fragmentation exacerbates POCD in aged mice anesthetized with isoflurane, and the mechanism is related to nerve injury induced by abnormality in hippocampal glutaminergic metabolism excitability.

Role of S1PR1 in dorsal root ganglion in remifentanil-induced hyperalgesia in rats with incisional pain / 中华麻醉学杂志

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.

Regulation of AMPA receptor on propofol induced hippocampal mitochondrial injury in neonatal rats / 中华危重病急救医学

Objective:To investigate whether propofol can cause injury to hippocampal mitochondria in neonatal rats and the regulation of excitatory amino acid receptor AMPA receptor.Methods:Forty-eight Sprague-Dawley (SD) rats aged 7 days were randomly divided into control group, propofol group, propofol+AMPA receptor agonist AMPA group (propofol+AMPA group) and propofol+AMPA receptor inhibitor CNQX group (propofol+CNQX group), with 12 rats in each group. The rats in the propofol groups were intraperitoneally injected with 30 mg/kg propofol, while in control group with 3 mg/kg normal saline. Each group was given 1/2 of the first dose every 20 minutes after the first administration, three times a day, for three consecutive days. The rats in the propofol+AMPA group and the propofol+CNQX group were injected with 1 g/L AMPA or CNQX 5 μL through left ventricle after the first administration. Three days after administration, the rats were sacrificed to obtain brain tissue. Western blotting was used to determine the expression of AMPA receptor glutamate receptors (GluR1, GluR2) subunit totally (T) and on membrane (M) in hippocampus. The expression of dynamin-related protein-1 (DRP-1) and phosphorylated-DRP-1 (p-DRP-1) and mitofusin 2 (Mfn2) related to mitochondrial fission and fusion were determined. The adenosine triphosphate (ATP) content and ATPase activity were determined.Results:Compared with the control group, GluR1 expression and its M/T ratio were significantly increased after treatment of propofol, GluR2 expression and its M/T ratio were significantly decreased, the ATP content and ATP-related enzyme activity were decreased significantly, while the expression of DRP-1 and its phosphorylation was significantly increased, and the expression of Mfn2 was significantly decreased. The changes indicated that repeated intraperitoneal injection of 30 mg/kg propofol leading to the injury of mitochondria in neural cells. Compared with the propofol group, the GluR1 expression and its M/T ratio further increased after AMPA agonist administration [T-GluR1 protein (T-GluR1/β-actin): 2.41±0.29 vs. 1.72±0.11, M-GluR1 protein (M-GluR1/β-actin): 1.18±0.15 vs. 0.79±0.09, M/T ratio: 0.78±0.12 vs. 0.46±0.08, all P < 0.01], GluR2 expression was significantly increased [T-GluR2 protein (T-GluR2/β-actin): 0.65±0.13 vs. 0.30±0.14, P < 0.01; M-GluR2 protein (M-GluR2/β-actin): 0.17±0.05 vs. 0.13±0.07, P > 0.05], but its M/T ratio was further decreased (0.27±0.10 vs. 0.41±0.08, P < 0.05). The ATP-related enzyme activity was further decreased, and the ATP content was further decreased (μmol/g: 0.32±0.07 vs. 0.70±0.10, P < 0.01). Mitochondria DRP-1 expression and its phosphorylation were further increased [DRP-1 protein (DRP-1/GAPDH): 2.75±0.36 vs. 1.70±0.19, p-DRP-1 protein (p-DRP-1/GAPDH): 0.99±0.14 vs. 0.76±0.15, both P < 0.05], and Mfn2 expression was further decreased (Mfn2/GAPDH: 0.23±0.12 vs. 0.54±0.12, P < 0.05). This indicated that the AMPA agonist increased the expression of the AMPA receptor GluR1 subunit on the cell membrane and shifted the GluR2 into the cell, thus increasing the mitochondrial injury caused by propofol. Compared with the propofol group, the GluR1 expression and its M/T ratio decreased significantly after AMPA inhibitor administration [T-GluR1 protein (T-GluR1/β-actin): 0.99±0.14 vs. 1.72±0.11, M-GluR1 protein (M-GluR1/β-actin): 0.21±0.07 vs. 0.79±0.09, M/T ratio: 0.21±0.07 vs. 0.46±0.08, all P < 0.01], the change of GluR2 expression was not significant, but its M/T ratio was significantly increased (0.59±0.09 vs. 0.41±0.08, P < 0.05). The ATP-related enzyme activity was increased significantly, and the ATP content was increased significantly (μmol/g: 0.87±0.12 vs. 0.70±0.10, P < 0.05). Mitochondria DRP-1 expression and its phosphorylation were significantly decreased [DRP-1 protein (DRP-1/GAPDH): 1.18±0.17 vs. 1.70±0.19, p-DRP-1 protein (p-DRP-1/GAPDH): 0.37±0.10 vs. 0.76±0.10, both P < 0.05], and Mfn2 expression was significantly increased (Mfn2/GAPDH: 0.78±0.10 vs. 0.54±0.12, P < 0.05). This indicated that AMPA inhibitor promoted the movement to the cell membrane of GluR2 subunits meanwhile inhibited the expression of GluR1 subunits, thus alleviating the injury of mitochondrial caused by propofol in the brain. Conclusions:Repeated intraperitoneal injection of 30 mg/kg propofol for 3 days can increase the expression of GluR1 subunits of AMPA receptor in 7-day neonatal rats hippocampus mainly distributing in the cell membrane, decrease the expression of GluR2 subunits moving into the cell, thus causing injury of mitochondrial function and dynamics, which can be aggravated by AMPA receptor agonist and alleviated by AMPA receptor inhibitors.

Effects of hydrogen gas on NOD-like receptor protein 3 inflammasomes in the cerebral cortex of rats with traumatic brain injury / 中华危重病急救医学

OBJECTIVE@#To investigate the effect of hydrogen gas on NOD-like receptor protein 3 (NLRP3) inflammasomes in the cerebral cortex of rats with traumatic brain injury (TBI).@*METHODS@#120 adult male Sprague-Dawley (SD) rates were randomly divided into 5 groups (n = 24): sham operation group (S group), TBI model group (T group), TBI+NLRP3 inhibitor MCC950 group (T+M group), TBI+hydrogen gas group (T+H group), TBI+hydrogen gas+MCC950 group (T+H+M group). TBI model was established by controlled cortical impact. NLRP3 inhibitor MCC950 (10 mg/kg) was intraperitoneally injected for 14 consecutive days before TBI operation in T+M and T+H+M groups. 2% hydrogen inhalation was given for 1 hour at 1 hour and 3 hours after TBI operation in T+H and T+H+M groups. At 6 hours after TBI operation, the pericontusional cortex tissues were obtained, the content of Evans blue (EB) was detected to evaluate the permeability of the blood-brain barrier. Water content in brain tissue was detected. The cell apoptosis was detected by TdT-mediated dUTP nick end labeling (TUNEL) and the neuronal apoptosis index was calculated. The expressions of Bcl-2, Bax, NLRP3, apoptosis-associated speck-like protein containing CARD (ASC) and caspase-1 p20 were detected by Western blotting. The levels of interleukins (IL-1β, IL-18) were detected by enzyme-linked immunosorbent assay (ELISA).@*RESULTS@#Compared with the S group, the content of EB in cerebral cortex, water content in brain tissue, apoptosis index and the expressions of Bax, NLRP3, ASC, caspase-1 p20 in T group were significantly increased, the expression of Bcl-2 was down-regulated, the levels of IL-1β and IL-18 were increased [the content of EB (μg/g): 87.57±6.89 vs. 10.54±1.15, water content in brain tissues: (83.79±2.74)% vs. (74.50±1.19)%, apoptotic index: (62.66±5.33)% vs. (4.61±0.96)%, Bax/β-actin: 4.20±0.44 vs. 1, NLRP3/β-actin: 3.55±0.31 vs. 1, ASC/β-actin: 3.10±0.26 vs. 1, caspase-1 p20/β-actin: 3.28±0.24 vs. 1, Bcl-2/β-actin: 0.23±0.03 vs. 1, IL-1β (ng/g): 221.58±19.15 vs. 27.15±3.27, IL-18 (ng/g): 87.26±7.17 vs. 12.10±1.85, all P < 0.05]. Compared with the T group, the T+M, T+H and T+H+M groups had significant reductions in the content of EB and water content in brain tissue, apoptotic index of the cerebral cortex, the expressions of Bax, NLRP3, and caspase-1 p20 in the brain tissue and the levels of IL-1β and IL-18, significant increases in the expression of Bcl-2. However, there was no significant difference in ASC expression. Compared with the T+H group, the content of EB in the cerebral cortex, water content in brain tissue, and apoptotic index, and the expressions of Bax, NLRP3 and caspase-1 p20 were further down-regulated in T+H+M group, the expression of Bcl-2 was further up-regulated, the levels of IL-1β and IL-18 were further decreased [the content of EB (μg/g): 40.49±3.15 vs. 51.96±4.69, water content in brain tissue: (76.58±1.04)% vs. (78.76±1.16)%, apoptotic index: (32.22±3.44)% vs. (38.54±3.89)%, Bax/β-actin: 1.92±0.16 vs. 2.56±0.21, NLRP3/β-actin: 1.94±0.14 vs. 2.37±0.24, caspase-1 p20/β-actin: 1.97±0.17 vs. 2.31±0.19, Bcl-2/β-actin: 0.82±0.07 vs. 0.52±0.04, IL-1β (ng/g): 86.23±7.09 vs. 110.44±10.48, IL-18 (ng/g): 40.18±3.22 vs. 46.23±4.02, all P < 0.05], but there were no statistical significance in all the indicators between T+M group and T+H group.@*CONCLUSIONS@#The mechanism by which hydrogen gas alleviates TBI may be related to inhibiting NLRP3 inflammasomes in the cerebral cortex of rats.

Effect of high-concentration hydrogen inhalation on sepsis-associated encephalopathy in mice / 中华麻醉学杂志

Objective:To evaluate the effect of high-concentration hydrogen inhalation on sepsis-associated encephalopathy (SAE) in mice.Methods:Healthy male ICR mice, aged 6-8 weeks, weighing 20-25 g, were divided into 4 groups ( n=50 each) using the random number table method: sham operation group (Sham group), SAE group, sham operation plus high-concentration hydrogen group (Sham+ H 2 group), and SAE plus high-concentration hydrogen group (SAE+ H 2 group). SAE model was prepared by cecal ligation and puncture (CLP) in anesthetized animals.At 1 and 6 h after operation, Sham+ H 2 and SAE+ H 2 groups inhaled the mixture of hydrogen and oxygen (67% hydrogen-33% oxygen) for 1 h, and Sham and SAE groups inhaled the mixture of nitrogen and oxygen (67% nitrogen-33% oxygen) for 1 h. The postoperative 7-day survival rate was recorded.Cognitive function was assessed by Y maze test at days 3, 5 and 7 after operation.The mice were sacrificed at 24 h after operation, and hippocampal tissues were obtained for microscopic examination of the pathological changes of neurons in hippocampal CA1 region (with a light microscope) and for determination of normal neuron count, contents of tumor necrosis factor-ɑ (TNF-α) and high mobility group box-1 (HMGB1) (by enzyme-linked immunosorbent assay), mitochondrial membrane potential (MMP) (by fluorescence spectrophotometry) and content of mitochondrial ATP (by fluorescein-fluorescent enzyme luminescence method). Results:Compared with Sham group, the 7-day survival rate after operation, percentage of spontaneous alternation at each time point after operation, and the number of normal neurons were significantly decreased, the contents of TNF-ɑ and HMGB1 were increased, and the contents of ATP and MMP were decreased in SAE and SAE+ H 2 groups ( P<0.05), and no significant change was found in Sham+ H 2 group ( P>0.05). Compared with SAE group, the 7-day survival rate after operation, percentage of spontaneous alternation at each time point after operation, and the number of normal neurons were significantly increased, the contents of TNF-ɑ and HMGB1 were decreased, and the contents of ATP and MMP were increased in SAE+ H 2 group ( P<0.05). Conclusions:High-concentration hydrogen inhalation can reduce SAE, and the mechanism may be related to reduction of hippocampal inflammatory responses and improvement in mitochondrial function in mice.

Relationship between autophagy and oxidative stress during remifentanil-induced hyperalgesia in rats with incisional pain / 中华麻醉学杂志

Objective:To evaluate the relationship between autophagy and oxidative stress during remifentanil-induced hyperalgesia in the rats with incisional pain.Methods:Thirty-two clean-grade healthy male Sprague-Dawley rats, weighing 230-250 g, aged 2-3 months, were divided into 4 groups ( n=8 each) using a random number table method: incisional pain group (I group), remifentanil + incisional pain group (RI group), autophagy inhibitor 3-methyladenine + remifentanil + incisional pain group (MRI group) and autophagy agonist rapamycin group + remifentanil + incisional pain group (RRI group). The model of incision pain was developed and the equal volume of normal saline was intravenously infused simultaneously for 60 min.In RI, MRI and RRI groups, the model of incision pain was developed and remifentanil 1 μg·kg -1·min -1 was simultaneously infused for 60 min.In MRI group, 3-methyladenine 15 mg/kg was intraperitoneally injected at 12 h before developing the model, and rapamycin 10 mg/kg was intraperitoneally injected at 12 h before developing the model in RRI group.Thermal paw withdrawal latency (TWL) and mechanical paw withdrawal threshold (MWT) were measured at 24 h before infusion of remifentanil or normal saline (T 0) and at 2, 6, 24 and 48 h after the end of infusion (T 1-4). The rats were sacrificed after the end of behavioral testing, and the lumbar enlargement segments of the spinal cord were harvested for determination of the expression of autophagy microtubule-associated protein 1 light chain 3Ⅱ (LC3Ⅱ), Beclin-1 and P62 (by Western blot), activity of superoxide dismutase (SOD) (by xanthine oxidase method) and content of malondialdehyde (MDA) (by thiobarbital method). Results:Compared with the baseline at T 0, PWT was significantly decreased and TWL was shortened at T 1-4 in the four groups ( P<0.05). Compared with I group, MWT was significantly decreased and TWL was shortened at T 1-4, the expression of LC3 Ⅱand Beclin-1 was up-regulated, the expression of P62 was down-regulated, SOD activity was decreased, and MDA content was increased in RI group ( P<0.05). Compared with RI group, MWT was significantly decreased and TWL was shortened at T 1-4, the expression of LC3 Ⅱand Beclin-1 was down-regulated, the expression of P62 was up-regulated, SOD activity was decreased, and MDA content was increased in MRI group ( P<0.05), and MWT was significantly increased and TWL was prolonged at T 1-4, the expression of LC3 Ⅱand Beclin-1 was up-regulated, the expression of P62 was down-regulated, SOD activity was increased, and MDA content was decreased in RRI group ( P<0.05). Conclusions:Autophagy is involved in the process of remifentanil-induced incisional hyperalgesia through regulating the level of oxidative stress in rats.

Identification of key genes for neuropathic pain in rats / 中华麻醉学杂志

Objective:To identify the key genes for neuropathic pain in rats.Methods:The genomic data of spinal cord tissues of rats (GSE18803) were downloaded from the Gene Expression Database at the American Center for Biotechnology Information to identify differentially expressed genes associated with neuropathic pain, and key genes were obtained by further analysis of the protein-protein interaction networks.Single-cell localization and expression of the key genes were analyzed by the Tabula Muris database.Results:The protein-protein interaction networks identified 10 hub genes, including Tyrobp, Clec4a3, C1qc, Ptprc, Laptm5, Csf1r, C1qa, C1qb, Fcgr3a, Cd53. Cd53, Laptm5 and Ptprc were mainly expressed in macrophages, B cells, NK cells, monocytes and granulocytes. Clec4a3 and Csf1r were mainly expressed in monocytes, Fcgr3a in monocytes and granulocytes, and Tyrobp in macrophages, monocytes, granulocytes, and pluripotent progenitor cells. Conclusions:Ten target genes associated with neuropathic pain are identified using bioinformatics, and their distribution and expression in immune inflammatory cells are obtained through comprehensive analysis.

Effects of hydrogen-rich saline on acute lung injury in rats with traumatic brain injury and role of Nrf2/HO-1 signaling pathway / 中华麻醉学杂志

Objective:To evaluate the effects of hydrogen-rich saline on acute lung injury in rats with traumatic brain injury (TBI) and the role of nuclear factor erythroid 2-related factor 2(Nrf2)/heme oxygenase-1 (HO-1) signaling pathway.Methods:Forty-eight adult male Sprague-Dawley rats, weighing 220-250 g, were divided into 4 groups ( n=12 each) using a random number table method: sham operation group (S group), TBI group (T group), TBI plus hydrogen-rich saline group (T+ H group), and TBI plus hydrogen-rich saline plus brusatol group (T+ H+ B group). TBI model was developed by controlled cortical impact.Nrf2 inhibitor brusatol 0.4 mg/kg was intraperitoneally injected every other day starting from 10 days before development of TBI model in T+ H+ B group.Hydrogen-rich fluid 10 ml/kg was intraperitoneally injected at 1 and 6 h after development of TBI model in T+ H group and T+ H+ B group.At 24 h after development of TBI model, the bronchoalveolar lavage fluid (BALF) was collected to detect the concentration of protein, blood samples from the right common carotid artery were collected and lung tissues were obtained for determination of the levels of tumor necrosis factor-alpha (TNF-α), interleukin-10 (IL-10) and high-mobility group box 1 protein (HMGB1) in serum and lung tissues (by enzyme-linked immunosorbent assay), wet to dry lung weight ratio (W/D ratio), expression of nuclear-Nrf2, total-Nrf2 and HO-1 in lung tissues (by Western blot), and expression of HO-1 mRNA (by real-time polymerase chain reaction) and for microscopic examination of histopathologic changes (by haematoxylin and eosin staining) which were scored. Results:Compared with S group, the concentrations of protein in BALF, W/D ratio of lung tissues and lung injury score were significantly increased, the levels of TNF-α, HMGB1 and IL-10 in serum and lung tissues were increased, and the expression of nuclear Nrf2, total Nrf2 and HO-1 protein and mRNA in lung tissues was up-regulated in T and T+ H groups ( P<0.05). Compared with T group, the concentrations of protein in BALF, W/D ratio of lung tissues and lung injury score were significantly decreased, the levels of TNF-α and HMGB1 in serum and lung tissues were decreased, the level of IL-10 in serum and lung tissues was increased, and the expression of nuclear Nrf2, total Nrf2 and HO-1 protein and mRNA in lung tissues was up-regulated in T+ H group ( P<0.05), and no significant changes were found in the parameters mentioned above in T+ H+ B group ( P>0.05). Compared with T+ H group, the concentrations of protein in BALF, W/D ratio of lung tissues and lung injury score were significantly increased, the levels of TNF-α and HMGB1 in serum and lung tissues were increased, the level of IL-10 in serum and lung tissues was decreased, and the expression of nuclear Nrf2, total Nrf2 and HO-1 protein and mRNA in lung tissues was down-regulated in T+ H+ B group ( P<0.05). Conclusions:Hydrogen-rich solution can alleviate acute lung injury in rats with traumatic brain injury, and the mechanism is related to activation of Nrf2/HO-1 signaling pathway and inhibition of the inflammatory responses.

Effects of endothelial progenitor cell-derived exosomes on neuronal injury induced by oxygen-glucose deprivation and restoration / 中华麻醉学杂志

Objective:To evaluate the effects of endothelial progenitor cell (EPC)-derived exosomes on neuronal injury induced by oxygen-glucose deprivation and restoration (OGD/R).Methods:HT22 neurons of mice were cultured and divided into 3 groups ( n=30 each) using a random number table method: control group (C group), OGD/R group and OGD/R plus EPC-derived exosome group (OGD/R+ EXO group). Cells in group C were cultured in normal atmosphere.In group OGD/R, the cells were exposed to 94%N 2-1%O 2-5%CO 2 for 6 h in glucose- and serum-free DMEM medium, followed by 24 h restoration of O 2 and glucose in the normal medium.In group OGD/R+ EXO, 20 μg/ml EPC-derived exosomes were added to the culture medium at 24 h before developing the model.EPCs were identified by immunofluorescence staining.Exosomes were identified by Western blot, transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA). Cell viability was measured by CCK-8 assay, the levels of malondialdehyde (MDA) and superoxide dismutase (SOD) were determined by enzyme-linked immunosorbent assay.The neuronal apoptosis was detected by TUNEL staining, and the apoptosis rate was calculated.The expression of Bax, Bcl-2, caspase-3, and cleaved caspase-3 was determined by Western blot, and cleaved caspase-3/caspase-3 ratio was calculated. Results:The cultured cells were EPCs, and EPC-derived exosomes were successfully extracted.Compared with group C, the cell viability was significantly decreased, the content of MDA was increased, the activity of SOD was decreased, the apoptosis rate was increased, the expression of Bax was up-regulated, the expression of Bcl-2 was down-regulated, and the ratio of cleaved-caspase-3/caspase-3 was increased in group OGD/R and group OGD/R+ EXO ( P<0.05). Compared with group OGD/R, the cell viability was significantly increased, the content of MDA was decreased, the activity of SOD was increased, the apoptosis rate was decreased, the expression of Bax was down-regulated, the expression of Bcl-2 was up-regulated, and the ratio of cleaved-caspase-3/caspase-3 was decreased in group OGD/R+ EXO ( P<0.05). Conclusions:EPC-derived exosomes can reduce OGD/R-induced neuronal injury, which is related to inhibition of oxidative stress and neuronal apoptosis.

Relationship between CCL21 and TREM2/DAP12 signaling pathways in spinal dorsal horn in remifentanil-induced hyperalgesia in mice with incisional pain / 中华麻醉学杂志

Objective:To evaluate the relationship between CCL21 and triggering receptor expressed on myeloid cells 2 (TREM2)/DNAX-activating protein of 12 kDa (DAP12) signaling pathways in the spinal dorsal horn in remifentanil-induced hyperalgesia in mice with incisional pain.Methods:Thirty-two SPF healthy male C57BL/6J mice, weighing 18-22 g, aged 8-10 weeks, were divided into 4 groups ( n=8 each) using a random number table method: control group (group C), CCL21 neutralizing antibody group (group anti-CCL21), remifentanil + incisional pain group (group R+ I), and CCL21 neutralizing antibody + remifentanil + incisional pain group (group anti-CCL21+ R+ I).A CCL21 neutralizing antibody 0.3 μg (diluted to 10 μl in normal saline) was intrathecally injected in anti-CCL21 and anti-CCL21+ R+ I groups twice a day.Normal saline 10 μl was intrathecally injected at the same time point twice a day in C and R+ I groups.Fifteen min after intrathecal injection, normal saline 0.1 ml was injected via the caudal vein for 4 consecutive times at an interval of 15 min in C and anti-CCL21 groups, and remifentanil 10 μg/kg (diluted to 0.1 ml in normal saline) was injected via the caudal vein for 4 consecutive times at an interval of 15 min in R+ I and anti-CCL21+ R+ I groups.The tail-flick latency (TFL) and mechanical paw withdrawal threshold (MWT) were measured at 24 h before remifentanil or normal saline injection (T 0) and 3, 6, 24 and 48 h after stopping injection of remifentanil or normal saline (T 1-4).The mice were sacrificed after the last measurement of pain threshold, and L 4-6 segments of the spinal cord were removed for determination of the expression of TREM2 and DAP12 protein and mRNA (by Western blot or quantitative real-time polymerase chain reaction). Results:Compared with group C, TFL was significantly shortened and MWT was decreased at T 1-4, and the expression of TREM2 and DAP12 protein and mRNA was up-regulated in group R+ I and R+ I+ anti-CCL21 ( P<0.05), and no significant change was found in the parameters mentioned above in group anti-CCL21 ( P>0.05).Compared with group R+ I, TFL was significantly prolonged and MWT was increased at T 1-4, and the expression of TREM2 and DAP12 protein and mRNA was down-regulated in group anti-CCL21+ R+ I ( P<0.05). Conclusions:CCL21 is involved in remifentanil-induced hyperalgesia by activating TREM2/DAP12 signaling pathways in the spinal dorsal horn of mice with incisional pain.

Effect of hydrogen-rich saline on mitochondrial biogenesis and dynamics in hippocampus of mice with sepsis-associated encephalopathy / 中华麻醉学杂志

Objective:To evaluate the effect of hydrogen-rich saline (HRS) on mitochondrial biogenesis and dynamics in hippocampus of mice with sepsis-associated encephalopathy (SAE).Methods:One hundred and twenty-eight male C57BL/6J mice, aged 6-8 weeks, weighing 20-25 g, were divided into 4 groups ( n=32 each) using a random number table method: sham operation group (Sham group), sham operation plus HRS group (Sham+ HRS group), SAE group and SAE plus HRS group.Sepsis was developed by cecal ligation and puncture (CLP) in anesthetized mice.HRS 10 ml/kg was intraperitoneally injected at 1 and 6 h after CLP in Sham+ HRS and SAE+ HRS groups.Twenty mice were randomly selected from each group to record the 7-day survival after operation.The working memory of the mice was observed by Y-maze test on days 3, 5 and 7 after CLP.The hippocampal tissues were obtained at 24 h after CLP for determination of the content of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and high-mobility group box 1 protein (HMGB1) (by enzyme-linked immunosorbent assay), activities of superoxide dismutase (SOD) and catalase (CAT) (by spectrophotometry), and expression of peroxisome proliferator-activated receptor gamma coactivator 1α (PGC-1α), nuclear respiratory factor 2 (NRF2), mitochondrial transcription factor A (Tfam), dynamin-related protein 1 (Drp1) and mitochondrial fusion protein mitofusin 2 (Mfn2) (by Western blot). Results:Compared with group Sham, the postoperative 7-day survival rate was significantly decreased, the time spent in novel arm was shortened, the contents of TNF-α, IL-6 and HMGB1 were increased, the activities of SOD and CAT were decreased, the expression of PGC-1α, NRF2 and Tfam was up-regulated, the expression of Drp1 was up-regulated, and the expression of Mfn2 was down-regulated in group SAE ( P<0.05). Compared with group SAE, the postoperative 7-day survival rate was significantly increased, the time spent in novel arm was prolonged, the contents of TNF-α, IL-6 and HMGB1 were decreased, the activities of SOD and CAT were increased, the expression of PGC-1α, NRF2 and Tfam was up-regulated, the expression of Drp1 was down-regulated, and the expression of Mfn2 was up-regulated in group SAE+ HRS ( P<0.05). Conclusions:The mechanism by which HRS alleviates SAE may be related to promotion of mitochondrial biogenesis, regulation of dynamics, and reduction of oxidative stress in hippocampus of mice.

A Role for Transmembrane Protein 16C/Slack Impairment in Excitatory Nociceptive Synaptic Plasticity in the Pathogenesis of Remifentanil-induced Hyperalgesia in Rats / 神经科学通报·英文版

Remifentanil is widely used to control intraoperative pain. However, its analgesic effect is limited by the generation of postoperative hyperalgesia. In this study, we investigated whether the impairment of transmembrane protein 16C (TMEM16C)/Slack is required for α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic receptor (AMPAR) activation in remifentanil-induced postoperative hyperalgesia. Remifentanil anesthesia reduced the paw withdrawal threshold from 2 h to 48 h postoperatively, with a decrease in the expression of TMEM16C and Slack in the dorsal root ganglia (DRG) and spinal cord. Knockdown of TMEM16C in the DRG reduced the expression of Slack and elevated the basal peripheral sensitivity and AMPAR expression and function. Overexpression of TMEM16C in the DRG impaired remifentanil-induced ERK1/2 phosphorylation and behavioral hyperalgesia. AMPAR-mediated current and neuronal excitability were downregulated by TMEM16C overexpression in the spinal cord. Taken together, these findings suggest that TMEM16C/Slack regulation of excitatory synaptic plasticity via GluA1-containing AMPARs is critical in the pathogenesis of remifentanil-induced postoperative hyperalgesia in rats.

Role of hemopexin in cerebral ischemia-reperfusion injury in rats / 中华麻醉学杂志

Objective:To evaluate the role of hemopexin (HPX) in cerebral ischemia-reperfusion (I/R) injury in rats.Methods:One hundred and twenty healthy male Sprague-Dawley rats, aged 7-8 weeks, weighing 250-280 g, were divided into sham operation group (S group, n=36), cerebral I/R group (I/R group, n=36), vehicle group (V group, n=24), and HPX group ( n=24). The model of cerebral I/R injury was established by 120 min middle cerebral artery occlusion followed by reperfusion in anesthetized rats.At 6, 12 and 24 h of reperfusion, 4 rats in S group and I/R group were sacrificed, and the ischemic penumbra of the ipsilateral cerebral cortex was obtained to detect the expression of HPX by Western blot.In I/R, V and HPX groups, 0.9% normal saline 10 μl, 0.1% NaN 3 10 μl, and 1.86 mg/ml HPX 10 μl were injected into the lateral ventricle, respectively, immediately after reperfusion.Eight rats in each group were selected, and neurological deficit was scored at 1-7 days of reperfusion.Eight rats in each group were sacrificed at 1 and 7 days of reperfusion, brains were removed, and brain tissues were obtained for measurement of infarct size, and the percentage of infarct size was calculated. Results:Compared with S group, the expression of HPX in cerebral ischemic penumbra was significantly up-regulated at 24 h of reperfusion in I/R group, and the neurological deficit scores were significantly decreased at 1-7 days of reperfusion, and the percentage of cerebral infarct size was increased at 1 and 7 days of reperfusion in I/R, V and HPX groups ( P<0.05). Compared with I/R group, the neurological deficit scores were significantly increased at 1-7 days of reperfusion, and the percentage of cerebral infarct size was decreased at 1 and 7 days of reperfusion in HPX group ( P<0.05), and no significant change was found in the above indicators in V and I/R groups ( P>0.05). Conclusion:Up-regulation of HPX expression is the endogenous protective mechanism of cerebral I/R injury in rats.

Effect of hydrogen on mitochondrial dynamics in hippocampus of mice with sepsis-associated encephalopathy / 中华麻醉学杂志

Objective:To evaluate the effect of hydrogen on mitochondrial dynamics in hippocampus of mice with sepsis-associated encephalopathy (SAE).Methods:A total of 224 clean-grade healthy male C57 mice, weighing 20-25g, aged 6-8 weeks, were divided into 4 groups ( n=56 each) using a random number table method: sham operation group (group Sham), sham operation + hydrogen group (group Sham+ H 2), SAE group and SAE + hydrogen group (group SAE+ H 2). Sepsis was produced by cecum ligation and puncture (CLP). Sham+ H 2and SAE+ H 2 groups inhaled 2% hydrogen for 1 h starting from 1 and 6 h after CLP, respectively.The postoperative 7-day survival rate was recorded.Brain tissues were obtained at 24 h after operation for examination of the pathological changes in hippocampal CA1 region (with a light microscope) and for determination of mitochondrial membrane potential (MMP) (by fluorescence spectrophotometry) and ATP content (by a bioluminescence assay) in hippocampal tissues.At 6, 12 and 24 h after operation, hippocampal mitochondria were isolated for determination of the expression of dynamin-related protein 1 (Drp1) and the mitochondrial fusion proteins mitofusin 2 (Mfn2) (by Western blot). Results:Compared with group Sham, the postoperative 7-day survival rate was significantly decreased, the contents of MMP and ATP were decreased, the expression of Drp1 was up-regulated, and the expression of Mfn2 was down-regulated( P<0.05), the pathological changes were aggravated in hippocampal CA1 region in SAE and SAE+ H 2 groups, and no significant change was found in the parameters mentioned above in group Sham+ H 2 ( P>0.05). Compared with group SAE, the postoperative 7-day survival rate was significantly increased, the contents of MMP and ATP were increased, the expression of Drp1 was down-regulated, and the expression of Mfn2 was up-regulated( P<0.05), the pathological changes were attenuated in hippocampal CA1 region in group SAE+ H 2. Conclusion:The mechanism by which hydrogen improves mitochondrial function is probably associated with promoting mitochondrial fusion and inhibiting mitochondrial fission in hippocampus of mice with SAE.

Effects of propofol on AMPA receptor expression in hippocampus of neonatal rats / 中华麻醉学杂志

Objective:To evaluate the effects of propofol on α-amino-3-hydroxy-5-methyl-4-isoxazole-propionate (AMPA) receptor expression in the hippocampus of neonatal rats.Methods:Eighty-four clean-grade healthy Sprague-Dawley rats of either sex, aged 7 days, weighing 14-18 g, were divided into 2 groups ( n=42 each) using a random number table method: control group (group C) and propofol group (group P). Propofol 30 mg/kg was intraperitoneally injected in group P, fat emulsion 3 mg/kg was intraperitoneally injected in group C, 1/2 of the initial dose was given at a 20 min interval, 3 times in total, for 3 consecutive days.The arterial blood samples were taken for blood gas analysis after administration on 1st day.The rats were sacrificed at 3, 7 and 28 days after the last administration of propofol, and the bilateral hippocampus was obtained for detection of the expression of AMPA receptors containing GluR1, GluR2 and GluR3 subunits in total and membrane protein (by Western blot), and the ratio of membrane protein to total protein (M/T) was calculated.The concentrations of free calcium ion were measured.The learning and memory ability was evaluated by Morris water maze test on 28 days after the last administration. Results:Compared with group C, the expression of AMPA receptor containing GluR1 subunit in total and membrane protein was significantly up-regulated, M/T was increased, the expression of AMPA receptor containing GluR2 subunit in total and membrane protein was down-regulated, and M/T was decreased at each time point ( P<0.05), no significant change was found in the expression of AMPA receptor containing GluR3 subunits ( P>0.05), the concentrations of free calcium ion in hippocampal cells were increased, and the escape latency was prolonged, the number of crossing the original platform was decreased, and the time of staying at the target quadrant was shortened at 2-4 days of training in group P ( P<0.05). Conclusion:The mechanism by which propofol reduces cognitive function is related to up-regulation of the expression of AMPA receptors containing GluR1 subunit in the hippocampus and down-regulation of the expression of AMPA receptors containing GluR2 subunits, which increases the concentration of free calcium ions in nerve cells of neonatal rats.

Relationship between G9a and Slack channels in dorsal root ganglia of rats with neuropathic pain / 中华麻醉学杂志

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.

Role of NOD2 in dorsal root ganglion in development of neuropathic pain in rats / 中华麻醉学杂志

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.

Role of spinal P2Y1R in development of remifentanil-induced hyperalgesia in rats with incisional pain: relationship with function of NR1 and NR2B in spinal cord / 中华麻醉学杂志

Objective:To evaluate the role of spinal P2Y1R in the development of remifentanil-induced hyperalgesia in rats with incisional pain (IP) and the relationship with the function of NR1 and NR2B in spinal cord.Methods:Forty-eight healthy adult male Sprague-Dawley rats, aged 10-12 weeks, weighing 250-280 g, in which intrathecal catheters were successfully placed, were divided into 6 groups ( n=8 each) using a random number table method: control group (group C), P2Y1R antagonist MRS2179 group (group M), remifentanil group (group R), remifentanil plus MRS2179 group (group R+ M), IP plus remifentanil group (group I+ R) and IP plus remifentanil plus MRS2179 group (group I+ R+ M). In group C, normal saline 10 μl was intrathecally injected, and 10 min later normal saline was infused for 60 min via the tail vein at a rate of 0.1 ml·kg -1·min -1.In group M, MRS2179 0.6 nmol/kg was intrathecally injected, and 10 min later normal saline was infused for 60 min via the tail vein at a rate of 0.1 ml·kg -1·min -1.In group R, normal saline 10 μl was intrathecally injected, and 10 min later remifentanil was infused for 60 min via the tail vein at a rate of 1 μg·kg -1·min -1.In group R+ M, MRS2179 0.6 nmol/kg was intrathecally injected, and 10 min later remifentanil was infused for 60 min at a rate of 1 μg·kg -1·min -1 via the tail vein.In group I+ R, normal saline 10 μl was intrathecally injected, 10 min later remifentanil was infused for 60 min via the tail vein at a rate of 1 μg·kg -1·min -1, and IP was established at 10 min after onset of remifentanil infusion.In group I+ R+ M, MRS2179 0.6 nmol/kg was intrathecally injected, 10 min later remifentanil was infused via the tail vein for 60 min at a rate of 1 μg·kg -1·min -1, and IP was established at 10 min after onset of remifentanil infusion.The mechanical paw withdrawal threshold (MWT), thermal paw withdrawal latency (TWL), and the number of paw lifts on the cold plate were measured at 24 h before infusion of remifentanil or normal saline and at 2, 6, 24, and 48 h after the end of infusion.The animals were sacrificed after the last measurement of the pain threshold, L 4-6 segments of the spinal cord were removed for determination of the expression of P2Y1R, phosphorylated NR1 (p-NR1), NR1, phosphorylated NR2B (p-NR2B) and NR2B (by Western blot), for calculation of the ratios of p-NR1/NR1 and p-NR2B/NR2B, and for detection of expression of P2Y1R mRNA, NR1 mRNA and NR2B mRNA (by real-time polymerase chain reaction). Results:Compared with group C, MWT was significantly decreased, TWL was shortened, the number of paw lifts on the cold plate was increased, the expression of P2Y1R protein and mRNA, NR1 protein and mRNA, p-NR1, NR2B protein and mRNA and p-NR2B was up-regulated, and p-NR1/NR1 ratio and p-NR2B/NR2B ratio were increased in group R ( P<0.01). Compared with group R, MWT was significantly increased, TWL was prolonged, the number of paw lifts on the cold plate was decreased, the expression of P2Y1R, p-NR1, NR1 protein and mRNA, p-NR2B, NR2B protein and mRNA was down-regulated, and p-NR1/NR1 ratio and p-NR2B/NR2B ratio were decreased in group R+ M ( P<0.05 or 0.01). Compared with group I+ R, MWT was significantly increased, TWL was prolonged, the number of paw lifts on the cold plate was decreased, the expression of P2Y1R, p-NR1, NR1 protein and mRNA, p-NR2B, NR2B protein and mRNA was down-regulated, and p-NR1/NR1 ratio and p-NR2B/NR2B ratio were decreased in group I+ R+ M ( P<0.01). Conclusion:Spinal P2Y1R can enhance the function of NR1 and NR2B, which may be involved in the development of remifentanil-induced hyperalgesia in rats with IP.