Objective:To evaluate the role of spinal Annexin A3 (ANXA3) in neuropathic pain in mice.Methods:Sixty-four SPF healthy adult male C57BL/6 mice, weighing 22-26 g, aged 8-10 weeks, were divided into 4 groups ( n=16 each) by the random number table method: sham operation group (group S), chronic constriction injury (CCI) group, CCI+ negative control adeno-associated virus AAV-NC group (group CCI+ N) and CCI+ adeno-associated virus AAV-shANXA3 group (group CCI+ sh). The neuropathic pain was induced by CCI of the sciatic nerve in anesthetized animals. The AAV-shANXA3 and AAV-NC (5 μl) were intrathecally injected at 14 days before developing the model in CCI+ N group and CCI+ sh group. The mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) were measured at 1 day before developing the model and at 7, 14 and 21 days after developing the model. All the mice were sacrificed after the last measurement of pain threshold, the L 4-6 segments of the spinal cord were removed for determination of the expression of ANXA3, phosphorylated nuclear factor-kappa B (p-NF-κB) and ionized calcium-binding adaptor molecule-1 (Iba-1)(by Western blot), expression of ANXA3 mRNA (by real-time polymerase chain reaction), microglial activation (using the immunofluorescence staining), and contents of pro-inflammatory cytokines tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β) and IL-6 and anti-inflammatory cytokines transforming growth factor-beta (TGF-β) and IL-10 (using enzyme-linked immunosorbent assay). Results:Compared with group S, the MWT was significantly decreased and TWL was shortened after developing the model, the expression of ANXA3 protein and mRNA, p-NF-κB and Iba-1 in spinal cord was up-regulated, the contents of TNF-α, IL-1β and IL-6 were increased, the contents of TGF-β and IL-10 were decreased ( P<0.05), the activation of microglia in the spinal cord was significantly increased, and the cell body was enlarged in group CCI. There was no significant difference in each parameter between group CCI and group CCI+ N ( P>0.05). Compared with CCI+ N group, the MWT was significantly increased on days 14 and 21 after developing the model, the TWL was prolonged on day 21 after developing the model, the expression of ANXA3 protein and mRNA, p-NF-κB and Iba-1 was down-regulated, the contents of TNF-α, IL-1β and IL-6 were decreased, the contents of TGF-β and IL-10 were increased ( P<0.05), and the activation of spinal microglia was decreased in CCI+ sh group. Conclusions:Spinal ANXA3 may be involved in the development and maintenance of neuropathic pain by activating the NF-κB signaling pathway and further promoting microglial activation in mice.

Objective:To investigate the effect of hydrogen on the expressions of stromal interaction molecule 1 (STIM1) and Ca 2+-release-activated-Ca 2+ channel protein 1 (Orai1) and the protective effect of hydrogen on septic mice acute lung injury (ALI). Methods:Forty-eight male ICR mice were divided into sham operation group (Sham group), hydrogen control group (Sham+H 2 group), sepsis group (SS group) and hydrogen intervention group (SS+H 2 group) according to a random number table method, with 12 mice in each group. Sepsis mice model were established by cecal ligation and puncture (CLP). Sham group and Sham+H 2 group did not undergo CLP, other operations were the same as follow. Sham+H 2 group and SS+H 2 group received 1 hour inhalation of 2% H 2 at 1 hour and 6 hours after CLP or sham operation. At 24 hours after CLP, 6 mice in each group were sacrificed for observing pulmonary microvascular permeability after injecting Evans blue (EB) through tail vein. Other 6 mice in each group were sacrificed for obtaining fresh lung tissue to observe the lung pathological change and lung wet/dry (W/D) weight ratio. The protein expressions and distribution of STIM1 and Orai1 in lung tissue were detected by Western blotting and immunofluorescence staining. The mRNA expressions of STIM1 and Orai1 in lung tissue were detected by reverse transcriotion-polymerase chain reaction (RT-PCR). Coimmunoprecipitation was used to observe STIM1-Orai1 interaction. Finally, pulmonary microvascular endothelial cells (PMVEC) of mice were cultured in vitro and randomly divided into four groups for inoculation onto culture plates: Control group, rich hydrogen solution group (Control+H 2 group), lipopolysaccharide (LPS) group and rich hydrogen solution intervention group (LPS+H 2 group). PMVECs in Control group and LPS group were cultured in normal medium. Control+H 2 group and LPS+H 2 group were cultured in saturated hydrogen medium. LPS group and LPS+H 2 group were added with LPS at 5 μg/mL. Intracellular Ca 2+ ([Ca 2+]i) concentration of PMVECs were detected by Fluo-4/AM green dye. Results:Compared with Sham group, the pathological score and lung W/D ratio were significantly increased in SS group at 24 hours after CLP (pathological score: 11.00±1.41 vs. 1.00±0.63, lung W/D ratio: 7.63±0.52 vs. 3.45±0.58, both P < 0.05), the content of EB in the lung tissue was increased (μg/g: 0.16±0.02 vs. 0.09±0.02, P < 0.05). Compared with SS group, the pathological score and lung W/D ratio were decreased in SS+H 2 group (pathological score: 3.50±1.05 vs. 11.00±1.41, lung W/D ratio: 4.45±0.45 vs. 7.63±0.52, both P < 0.05), the content of EB in the lung tissue was decreased (μg/g: 0.13±0.02 vs. 0.16±0.02, P < 0.05), which prove that hydrogen can improve ALI caused by sepsis. Compared with Sham group, the protein and mRNA expressions of STIM1 and Orai1 were up-regulated in SS group (relative expression level of STIM1 protein: 3.08±0.32 vs. 1.00±0.00, relative expression level of STIM1 mRNA: 3.65±0.24 vs. 1.00±0.00, relative expression level of Orai1 protein: 3.63±0.23 vs. 1.00±0.00, relative expression level of Orai1 mRNA: 3.80±0.22 vs. 1.00±0.00, all P < 0.05), while the protein and mRNA expressions of STIM1 and Orai1 were down-regulated in SS+H 2 group compared with SS group (relative expression level of STIM1 protein: 1.78±0.13 vs. 3.08±0.32, relative expression level of STIM1 mRNA: 1.76±0.28 vs. 3.65±0.24, relative expression level of Orai1 protein: 1.92±0.22 vs. 3.63±0.23, relative expression level of Orai1 mRNA: 1.85±0.18 vs. 3.80±0.22, all P < 0.05). Coimmunoprecipitation staining results showed that there was no statistically significance in the association between STIM1 and Orai1 in Sham group and Sham+H 2 group. Compared with Sham group, the STIM1-Orai1 interaction was increased in SS group (relative expression level: 3.71±0.37 vs. 1.00±0.00, P < 0.05), while the STIM1-Orai1 interaction was decreased in SS+H 2 group compared with SS group (relative expression level: 2.17±0.29 vs. 3.71±0.37, P < 0.05). There were no statistically significant differences in various indicators between Sham group and Sham+H 2 group. In vitro, the intracellular [Ca 2+]i concentration in PMVECs was increased in LPS group compared with Control group using Fluo-4/AM green dye. The intracellular [Ca 2+]i concentration in PMVECs was decreased in LPS+H 2 group compared with LPS group. Conclusion:The protective effect of hydrogen on lung tissues in septic mice is related to the inhibition of STIM1, Orai1 and the interaction between them.

Objective:To evaluate the role of spinal Annexin A3 (ANXA3) in neuropathic pain in mice.Methods:Sixty-four SPF healthy adult male C57BL/6 mice, weighing 22-26 g, aged 8-10 weeks, were divided into 4 groups ( n=16 each) by the random number table method: sham operation group (group S), chronic constriction injury (CCI) group, CCI+ negative control adeno-associated virus AAV-NC group (group CCI+ N) and CCI+ adeno-associated virus AAV-shANXA3 group (group CCI+ sh). The neuropathic pain was induced by CCI of the sciatic nerve in anesthetized animals. The AAV-shANXA3 and AAV-NC (5 μl) were intrathecally injected at 14 days before developing the model in CCI+ N group and CCI+ sh group. The mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) were measured at 1 day before developing the model and at 7, 14 and 21 days after developing the model. All the mice were sacrificed after the last measurement of pain threshold, the L 4-6 segments of the spinal cord were removed for determination of the expression of ANXA3, phosphorylated nuclear factor-kappa B (p-NF-κB) and ionized calcium-binding adaptor molecule-1 (Iba-1)(by Western blot), expression of ANXA3 mRNA (by real-time polymerase chain reaction), microglial activation (using the immunofluorescence staining), and contents of pro-inflammatory cytokines tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β) and IL-6 and anti-inflammatory cytokines transforming growth factor-beta (TGF-β) and IL-10 (using enzyme-linked immunosorbent assay). Results:Compared with group S, the MWT was significantly decreased and TWL was shortened after developing the model, the expression of ANXA3 protein and mRNA, p-NF-κB and Iba-1 in spinal cord was up-regulated, the contents of TNF-α, IL-1β and IL-6 were increased, the contents of TGF-β and IL-10 were decreased ( P<0.05), the activation of microglia in the spinal cord was significantly increased, and the cell body was enlarged in group CCI. There was no significant difference in each parameter between group CCI and group CCI+ N ( P>0.05). Compared with CCI+ N group, the MWT was significantly increased on days 14 and 21 after developing the model, the TWL was prolonged on day 21 after developing the model, the expression of ANXA3 protein and mRNA, p-NF-κB and Iba-1 was down-regulated, the contents of TNF-α, IL-1β and IL-6 were decreased, the contents of TGF-β and IL-10 were increased ( P<0.05), and the activation of spinal microglia was decreased in CCI+ sh group. Conclusions:Spinal ANXA3 may be involved in the development and maintenance of neuropathic pain by activating the NF-κB signaling pathway and further promoting microglial activation in mice.

Objective:To investigate the effect of hydrogen on the expressions of stromal interaction molecule 1 (STIM1) and Ca 2+-release-activated-Ca 2+ channel protein 1 (Orai1) and the protective effect of hydrogen on septic mice acute lung injury (ALI). Methods:Forty-eight male ICR mice were divided into sham operation group (Sham group), hydrogen control group (Sham+H 2 group), sepsis group (SS group) and hydrogen intervention group (SS+H 2 group) according to a random number table method, with 12 mice in each group. Sepsis mice model were established by cecal ligation and puncture (CLP). Sham group and Sham+H 2 group did not undergo CLP, other operations were the same as follow. Sham+H 2 group and SS+H 2 group received 1 hour inhalation of 2% H 2 at 1 hour and 6 hours after CLP or sham operation. At 24 hours after CLP, 6 mice in each group were sacrificed for observing pulmonary microvascular permeability after injecting Evans blue (EB) through tail vein. Other 6 mice in each group were sacrificed for obtaining fresh lung tissue to observe the lung pathological change and lung wet/dry (W/D) weight ratio. The protein expressions and distribution of STIM1 and Orai1 in lung tissue were detected by Western blotting and immunofluorescence staining. The mRNA expressions of STIM1 and Orai1 in lung tissue were detected by reverse transcriotion-polymerase chain reaction (RT-PCR). Coimmunoprecipitation was used to observe STIM1-Orai1 interaction. Finally, pulmonary microvascular endothelial cells (PMVEC) of mice were cultured in vitro and randomly divided into four groups for inoculation onto culture plates: Control group, rich hydrogen solution group (Control+H 2 group), lipopolysaccharide (LPS) group and rich hydrogen solution intervention group (LPS+H 2 group). PMVECs in Control group and LPS group were cultured in normal medium. Control+H 2 group and LPS+H 2 group were cultured in saturated hydrogen medium. LPS group and LPS+H 2 group were added with LPS at 5 μg/mL. Intracellular Ca 2+ ([Ca 2+]i) concentration of PMVECs were detected by Fluo-4/AM green dye. Results:Compared with Sham group, the pathological score and lung W/D ratio were significantly increased in SS group at 24 hours after CLP (pathological score: 11.00±1.41 vs. 1.00±0.63, lung W/D ratio: 7.63±0.52 vs. 3.45±0.58, both P < 0.05), the content of EB in the lung tissue was increased (μg/g: 0.16±0.02 vs. 0.09±0.02, P < 0.05). Compared with SS group, the pathological score and lung W/D ratio were decreased in SS+H 2 group (pathological score: 3.50±1.05 vs. 11.00±1.41, lung W/D ratio: 4.45±0.45 vs. 7.63±0.52, both P < 0.05), the content of EB in the lung tissue was decreased (μg/g: 0.13±0.02 vs. 0.16±0.02, P < 0.05), which prove that hydrogen can improve ALI caused by sepsis. Compared with Sham group, the protein and mRNA expressions of STIM1 and Orai1 were up-regulated in SS group (relative expression level of STIM1 protein: 3.08±0.32 vs. 1.00±0.00, relative expression level of STIM1 mRNA: 3.65±0.24 vs. 1.00±0.00, relative expression level of Orai1 protein: 3.63±0.23 vs. 1.00±0.00, relative expression level of Orai1 mRNA: 3.80±0.22 vs. 1.00±0.00, all P < 0.05), while the protein and mRNA expressions of STIM1 and Orai1 were down-regulated in SS+H 2 group compared with SS group (relative expression level of STIM1 protein: 1.78±0.13 vs. 3.08±0.32, relative expression level of STIM1 mRNA: 1.76±0.28 vs. 3.65±0.24, relative expression level of Orai1 protein: 1.92±0.22 vs. 3.63±0.23, relative expression level of Orai1 mRNA: 1.85±0.18 vs. 3.80±0.22, all P < 0.05). Coimmunoprecipitation staining results showed that there was no statistically significance in the association between STIM1 and Orai1 in Sham group and Sham+H 2 group. Compared with Sham group, the STIM1-Orai1 interaction was increased in SS group (relative expression level: 3.71±0.37 vs. 1.00±0.00, P < 0.05), while the STIM1-Orai1 interaction was decreased in SS+H 2 group compared with SS group (relative expression level: 2.17±0.29 vs. 3.71±0.37, P < 0.05). There were no statistically significant differences in various indicators between Sham group and Sham+H 2 group. In vitro, the intracellular [Ca 2+]i concentration in PMVECs was increased in LPS group compared with Control group using Fluo-4/AM green dye. The intracellular [Ca 2+]i concentration in PMVECs was decreased in LPS+H 2 group compared with LPS group. Conclusion:The protective effect of hydrogen on lung tissues in septic mice is related to the inhibition of STIM1, Orai1 and the interaction between them.

Objective:To evaluate the role of neuronal nitric oxide synthase (nNOS)-nitric oxide synthase 1 adaptor protein (NOS1AP) coupling in remifentanil-induced hyperalgesia in rats.Methods:Forty clean-grade healthy adult male Sprague-Dawley rats, weighing 240-260 g, aged 2-3 months, were divided into 4 groups ( n=10 each) using a random number table method: control group (group C), remifentanil group (group R), nNOS-NOS1AP inhibitor ZLc002 group (group C+ Z) and remifentanil + ZLc002 group (group R+ Z). Normal saline was intravenously infused at a rate of 0.1 ml·kg -1·min -1 for 60 min in C group. Remifentanil was intravenously infused at a rate of 1.0 μg·kg -1·min -1 for 60 min in R group. ZLc002 10 mg/kg was intraperitoneally injected for 3 consecutive days, and then normal saline 0.1 ml·kg -1·min -1 and remifentanil 1.0 μg·kg -1·min -1 were intravenously infused for 60 min in C+ Z group and R+ Z group. The mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) were measured at 24 h before intravenous infusion and 6, 24 and 48 h after intravenous infusion (T 0-3). All the rats were sacrificed after the last measurement of pain thresholds, and the L 4-6 segments of the spinal cord were removed for determination of the expression of nNOS, NOS1AP and Dexamethasone-induced Ras-related protein 1 (Dexras1) protein and mRNA using the real-time polymerase chain reaction. Nitrosylated proteins were extracted by biotin conversion for determination of the expression of nNOS, NOS1AP and total and nitrosylated Dexras1 (by Western blot) and co-expression of nNOS-NOS1AP (by co-immunoprecipitation). The content of NO in the spinal cord was measured. Results:Compared with group C, the MWT was significantly decreased, and the TWL was shortened at T 1-3, the expression of nNOS and NOS1AP protein and mRNA was up-regulated, the co-expression of nNOS-NOS1AP and NO production were increased, and the expression of nitrosylated Dexras1 was up-regulated in group R ( P<0.05), and no significant change was found in each aforementioned parameter in group C+ Z ( P>0.05). Compared with group R, the MWT was significantly increased, and the TWL was prolonged at T 1-3, the co-expression of nNOS-NOS1AP and NO production were decreased, the expression of nitrosylated Dexras1 was down-regulated ( P<0.05), and no significant change was found in the expression of nNOS and NOS1AP protein and mRNA in group R+ Z ( P>0.05). There were no significant differences in total Dexras1 protein and mRNA expression among the four groups ( P>0.05). Conclusions:The mechanism by which remifentanil induces hyperalgesia may be related to up-regulating the expression of nNOS and NOS1AP in the spinal cord, promoting interaction between nNOS and NOS1AP and mediating NO generation and Dexras1 nitrosylation modification in rats.

Objective:To evaluate the role of Ras homolog gene family member A (RhoA) in hydrogen-induced alleviation of lipopolysaccharide (LPS)-caused damage to pulmonary microvascular endothelial cell(PMVEC) barrier function in mice.Methods:PMVECs were cultured in DMEM/F12 medium containing 10% fetal bovine serum and 1% penicillin/streptomycin until 4-6 passage. These cells were divided into 6 groups ( n=36 each) using a random number table method: control group (group A), hydrogen-rich medium group (group B), LPS group (group C), LPS + hydrogen-rich medium group (group D), LPS + RhoA inhibitor C3 enzyme group (group E) and LPS + hydrogen-rich medium + RhoA agonist U-46619 group (group F). Cells were cultured within normal medium in group A, group C and group E and within hydrogen-rich medium in group B, group D and group F. LPS at a final concentration of 1 μg/ml was simultaneously added in group C, group D, group E and group F. C3 enzyme at a final concentration of 3 μg/ml was added at 2 h before addition of LPS in group E. U-46619 at a final concentration of 10 mg/ml was added at 3 h before addition of LPS in group F. The expression of vascular endothelial (VE)-cadherin and occludin was determined by Western blot at 6, 12 and 24 h after incubation with LPS. At 24 h after incubation with LPS, the release rate of LDH was measured by LDH method, cell viability was measured by MTT method, and the activity of RhoA was determined by GST pull-down method. Results:Compared with group A, the expression of VE-cadherin and occludin was significantly down-regulated at 6, 12 and 24 h of incubation, the cell viability was decreased at 24 h of incubation, and the release rate of LDH and activity of RhoA were increased in group C ( P<0.05). Compared with group C, the expression of VE-cadherin and occludin was significantly up-regulated at 6, 12 and 24 h of incubation, the cell viability was increased at 24 h of incubation, and the release rate of LDH and activity of RhoA were decreased in group D ( P<0.05). Compared with group C, the expression of VE-cadherin and occludin was significantly up-regulated at 6, 12 and 24 h of incubation, the cell viability was increased at 24 h of incubation, and the release rate of LDH and activity of RhoA were decreased in group E ( P<0.05). Compared with group D, the expression of VE-cadherin and occludin was significantly down-regulated at 6, 12 and 24 h of incubation, the cell viability was decreased at 24 h of incubation, and the release rate of LDH and activity of RhoA were increased in group F ( P<0.05). Conclusions:RhoA is involved in hydrogen-induced alleviation of LPS-caused damage to PMVEC barrier function in mice.

Objective:To investigate the relationship between S-nitrosylation of spinal divalent metal transporter 1 (DMT1) modification and mechanism of remifentanil-induced hyperalgesia in rats.Methods:Forty pathogen-free healthy male Sprague-Dawley rats, aged 2-3 months, weighing 240-260 g, were divided into 4 groups ( n=10 each) using a random number table method: control group (group C), remifentanil group (group R), L-NAME group (group C+ L) and remifentanil+ L-NAME group (group R+ L). Normal saline was infused at a rate of 0.1 ml·kg -1·min -1 for 60 min via the caudal vein in C group. Remifentanil was infused at a rate of 1.0 μg·kg -1·min -1 for 60 min via the caudal vein in R group. L-NAME 30 mg/kg was intraperitoneally injected, and 10 min later normal saline was infused at a rate of 0.1 ml·kg -1·min -1 for 60 min in C+ L group. L-NAME 30 mg/kg was intraperitoneally injected, and 10 min later remifentanil was infused at a rate of 1.0 μg·kg -1·min -1 for 60 min in R+ L group. The mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) were measured at 24 h before iv infusion and 6, 24 and 48 h after the end of infusion (T 0-3). All the rats were sacrificed under anesthesia after the last measurement of pain thresholds, and the L 4-6 segments of the spinal cord were removed for determination of the expression of neuronal nitric oxide sythases (nNOS) and DMT1 mRNA (using quantitative real-time polymerase chain reaction), extraction of nitrosylated proteins (by biotin switch assay), expression of nNOS, total DMT1 and S-nitrosylation of DMT1 (by Western blot), nitric oxide (NO) content (by spectrophotometry) and iron content (using atomic absorption spectrophotometer). Results:Compared with group C, the MWT was significantly decreased, and the TWL was shortened at T 1-3 in group R ( P<0.05), and the expression of nNOS protein and mRNA and S-nitrosylation of DMT1 was significantly up-regulated, and contents of NO and iron were increased in R and R+ L groups ( P<0.05), and no significant change was found in each index in group C+ L ( P>0.05). Compared with group R, the MWT was significantly increased, and the TWL was prolonged at T 1-3, and the expression of nNOS protein and mRNA and S-nitrosylation of DMT1 was down-regulated, and contents of NO and iron were decreased in group R+ L ( P<0.05). Compared with group C+ L, the MWT was significantly decreased, and the TWL was shortened at T 1-3, and the expression of nNOS protein and mRNA and S-nitrosylation of DMT1 was up-regulated, and the contents of NO and iron were increased in group R+ L ( P<0.05). There were no significant differences in the expression of DMT1 mRNA and total DMT1 in spinal cord among all the groups ( P>0.05). Conclusions:Activation of nNOS induces an increase in NO generation in the spinal cord and mediates the S-nitrosylation of DMT1, which may be related to the mechanism of remifentanil-induced hyperalgesia in rats.

【Objective】 To explore the distribution of ApoE polymorphism in Shaanxi province and its correlation with lipid level and coronary heart disease type. 【Methods】 ApoE genotypes in the whole blood of 11 533 patients with cardiovascular diseases admitted to The First Affiliated Hospital of Xi’an Jiaotong University from January 2019 to December 2019 were detected by PCR-fluorescent probe method. Then 3 884 patients with coronary heart disease were selected to detect the lipid level and classified for the analysis of ApoE polymorphism. 【Results】 The proportion of E2/E2, E2/E3, E3/E3, E2/E4, E4/E4 and E3/E4 was 0.69%, 11.66%, 70.31%, 1.17%, 0.83% and 15.34%, respectively. E3 genotype was the highest (71.48%), followed by E4 (16.17%), and E2 was the least (12.35%). There was no statistical difference in the distribution of ApoE polymorphism in patients with cardiovascular disease accompanied with or without coronary heart disease. Compared with those of E2, the total cholesterol (TC) and low-density lipoprotein (LDL-C) levels of E3 and E4 increased significantly (P<0.001). Compared with that of E3 type, triglyceride (TG) level of E2 type and E4 type increased (P<0.050). The genotype of ApoE was correlated with the type of coronary heart disease (P<0.001). The genotype of ApoE was significantly different from that of stable and unstable angina pectoris in ischemic cardiomyopathy (P<0.001), but not statistically different from that of acute myocardial infarction (P>0.008 3). 【Conclusion】 The polymorphism of ApoE in Shaanxi is mainly E3 type, and there is no statistical difference in the distribution of coronary heart disease and other cardiovascular diseases. ApoE gene polymorphism is correlated with blood lipid level and coronary heart disease, but the relationship with different types of coronary heart disease needs to be further determined.

Objective To evaluate the effect of remifentanil on iron metabolism in spinal dorsal horn neurons of rats.Methods The primary spinal dorsal horn neurons of rats were seeded in the culture plate at a density of 2× 105 cells/well and divided into 4 groups using a random number table method:control group (C group,n=40),remifentanil group (R group,n=40),divalent metal transporter 1 without iron-responsive element [DMT1 (-) IRE] siRNA group (siRNA group,n=32) and DMT1 (-) IRE siRNA plus remifentanil group (siRNA+R group,n=32).siRNA and siRNA+R groups were subjected to DMT1 (-) IRE siRNA transfection on day 3 of culture.R and siRNA+R groups were incubated for 60 min in the solution with remifentanil at a final concentration of 40 nmol/L.The contents of reactive oxygen species (ROS) and Fe2+ were determined by fluorescent probe method,the malondialdehyde (MDA) content was detected by TBA method,and the content of labile iron pool (LIP) was detected by calcein AM and iron chelator at the end of incubation with remifentanil in R and siRNA+R groups and at the corresponding time points in the other groups.The expression of DMT1 (-) IRE and DMT1 (+) IRE was determined by Westem blot in C and R groups.Results Compared with C group,the expression of DMT1 (-) IRE in the spinal dorsal horn neurons was significantly up-regulated,the contents of Fe2+,LIP,ROS and MDA were increased (P＜0.05),and no significant change was found in the expression of DMT1 (+) IRE in R group (P＞0.05).Compared with R group,the contents of Fe2+,LIP,ROS and MDA in the spinal dorsal horn neurons were significantly decreased in siRNA+R group (P＜0.05).Conclusion Remifentanil increases the iron content of spinal dorsal horn neurons by activating DMT1 (-) IRE,which may be associated with the mechanism of remifentanil-induced postoperative hyperalgesia in rats.

Objective To evaluate the changes in the expression of artemin in skin around the inci-sion during remifentanil-induced hyperalgesia in the rats with incisional pain. Methods Thirty-two healthy male Sprague-Dawley rats, aged 10-12 weeks, weighing 250-280 g, were divided into 4 groups (n = 8 each) using a random number table: control group (group C), incisional pain group (group I), remifen-tanil group (group R) and incisional pain plus remifentanil group (group I+R). Remifentanil was intrave-nously infused for 60 min at a rate of 1 μg·kg-1 ·min-1 in group R. In group I, the model of incisional pain was established, and the equal volume of normal saline was infused for 60 min via the tail vein at the same time. In group I+R, the model of incisional pain was established, and remifentanil was infused for 60 min via the tail vein at a rate of 1 μg·kg-1 ·min-1 at the same time. The equal volume of normal saline was infused for 60 min via the tail vein in group C. Mechanical paw withdrawal threshold (MWT) and ther-mal paw withdrawal latency (TWL) were measured at 24 h before infusion of remifentanil or normal saline and 2, 6, 24 and 48 h after the end of infusion (T0-4 ). Rats were sacrificed following the last measurement of pain threshold, and ipsilateral plantar skin was removed for detection of the expression of artemin protein and mRNA (by fluorescent quantitative real-time polymerase chain reaction or Western blot). Results Compared with group C, MWT was significantly decreased and TWL was shorten at T1-4 , and the expression of artemin protein and mRNA in plantar skin was up-regulated in R, I and I+R groups (P<0. 01). Compared with R and I groups, MWT was significantly decreased and TWL was shorten at T1-4 , and the ex-pression of artemin protein and mRNA in plantar skin was up-regulated in group I+R (P<0. 01). Conclu-sion The peripheral mechanism by which remifentanil induces hyperalgesia may be related to up-regulated expression of artemin in skin around the incision in the rats with incisional pain.