MicroRNA-7a-5p ameliorates diabetic peripheral neuropathy by regulating VDAC1/JNK/c-JUN pathway.

AIMS: The pathogenesis of diabetic peripheral neuropathy (DPN) is complex, and its treatment is extremely challenging. MicroRNA-7a-5p (miR-7a-5p) has been widely reported to alleviate apoptosis and oxidative stress in various diseases. This study aimed to investigate the mechanism of miR-7a-5p in DPN. METHODS: DPN cell model was constructed with high-glucose-induced RSC96 cells. Cell apoptosis and viability were detected by flow cytometry analysis and cell counting kit-8 (CCK-8) assay respectively. The apoptosis and Jun N-terminal kinase (JNK)/c-JUN signalling pathway-related proteins expression were detected by Western blotting. The intracellular calcium content and oxidative stress levels were detected by flow cytometry and reagent kits. Mitochondrial membrane potential was evaluated by tetrechloro-tetraethylbenzimidazol carbocyanine iodide (JC-1) staining. The targeting relationship between miR-7a-5p and voltage-dependent anion-selective channel protein 1 (VDAC1) was determined by RNA pull-down assay and dual-luciferase reporter gene assay. The streptozotocin (STZ) rat model was constructed to simulate DPN in vivo. The paw withdrawal mechanical threshold (PTW) was measured by Frey capillary line, and the motor nerve conduction velocity (MNCV) was measured by electromyography. RESULTS: MiR-7a-5p expression was decreased, while VDAC1 expression was increased in HG-induced RSC96 cells and STZ rats. In HG-induced RSC96 cells, miR-7a-5p overexpression promoted cell proliferation, inhibited apoptosis, down-regulated calcium release, improved mitochondrial membrane potential and repressed oxidative stress response. MiR-7a-5p negatively regulated VDAC1 expression. VDAC1 knockdown improved cell proliferation activity, suppressed cell apoptosis and mitochondrial dysfunction by inhibiting JNK/c-JUN pathway activation. MiR-7a-5p overexpression raised PTW, restored MNCV and reduced oxidative stress levels and nerve cell apoptosis in STZ rats. CONCLUSION: MiR-7a-5p overexpression ameliorated mitochondrial dysfunction and inhibited apoptosis in DPN by regulating VDAC1/JNK/c-JUN pathway.

Lysine demethylase KDM5B down-regulates SIRT3-mediated mitochondrial glucose and lipid metabolism in diabetic neuropathy.

BACKGROUND: Diabetic peripheral neuropathy (DPN) is a common neurological complication of diabetes mellitus without efficient interventions. Both lysine demethylase 5B (KDM5B) and sirtuin-3 (SIRT3) have been found to regulate islet function and glucose homeostasis. KDM5B was predicted to bind to the SIRT3 promoter by bioinformatics. Here, we investigated whether KDM5B affected DPN development via modulating SIRT3. METHODS: The db/db mice and high glucose-stimulated Schwann cells (RSC96) were used as in vivo and in vitro models of DPN, respectively. Glucose level, glucose and insulin tolerance of mice were measured. Neurological function was evaluated by motor nerve conduction velocity (MNCV), tactile allodynia assay and thermal sensitivity assay. Adenosine triphosphate level, oxygen consumption rate, extracellular acidification rate, ß-oxidation rate, acetyl-CoA level, acetylation levels and activities of long-chain acyl CoA dehydrogenase (LCAD) and pyruvate dehydrogenase (PDH) were detected. Methyl thiazolyl tetrazolium assay was adopted to determine cell viability. Reactive oxygen species (ROS) production was detected by MitoSox staining. Western blotting for measuring target protein levels. Molecular mechanisms were investigated by co-immunoprecipitine (Co-IP), chromatin immunoprecipitation (ChIP) and luciferase reporter assay. RESULTS: KDM5B was up-regulated, while SIRT3 was down-regulated in DPN models. SIRT3 overexpression or AMPK activation ameliorated mitochondrial metabolism dysfunction and ROS overproduction during DPN. KDM5B overexpression triggered mitochondrial metabolism disorder and oxidative stress via directly transcriptional inhibiting SIRT3 expression by demethylating H3K4me3 or indirectly repressing AMPK pathway-regulated SIRT3 expression. CONCLUSION: KDM5B contributes to DPN via regulating SIRT3-mediated mitochondrial glucose and lipid metabolism. KDM5B inhibition may be an effective intervention for DPN.

Remimazolam tosilate in upper gastrointestinal endoscopy: A multicenter, randomized, non-inferiority, phase III trial.

BACKGROUND AND AIM: Remimazolam tosilate (RT) is a new short-acting GABA(A) receptor agonist, having potential to be an effective option for procedural sedation. Here, we aimed to compare the efficacy and safety of RT with propofol in patients undergoing upper gastrointestinal endoscopy. METHODS: This positive-controlled, non-inferiority, phase III trial recruited patients at 17 centers, between September 2017 and November 2017. A total of 384 patients scheduled to undergo upper gastrointestinal endoscopy were randomly assigned to receive RT or propofol. Primary endpoint was the success rate of sedation. Adverse events (AEs) were recorded to evaluate safety. RESULTS: The success rate of sedation in the RT group was non-inferior to that in the propofol group (97.34% vs 100.00%; difference in rate -2.66%, 95% CI -4.96 to -0.36, meeting criteria for non-inferiority). Patients in the RT group had longer time to adequate sedation (P < 0.0001) but shorter time to fully alert (P < 0.0001) than that in the propofol group. The incidences of hypotension (13.04% vs 42.86%, P < 0.0001), treatment-related hypotension (0.54% vs 5.82%, P < 0.0001), and respiratory depression (1.09% vs 6.88%, P = 0.0064) were significantly lower in the RT group. AEs were reported in 74 (39.15%) patients in the RT group and 114 (60.32%) patients in the propofol group, with significant difference (P < 0.0001). CONCLUSION: This trial established non-inferior sedation success rate of RT compared with propofol. RT allows faster recovery from sedation compared with propofol. The safety profile is favorable and appears to be superior to propofol, indicating that it was feasible and well tolerated for patients.

Spinal peroxynitrite contributes to remifentanil-induced postoperative hyperalgesia via enhancement of divalent metal transporter 1 without iron-responsive element-mediated iron accumulation in rats.

BACKGROUND: Hyperalgesia is one of the negative consequences following intraoperative analgesia with remifentanil. Peroxynitrite is a critical determinant in nociceptive process. Peroxynitrite inactivates iron-sulfur cluster that results in mitochondrial dysfunction and the release of iron, leading to mitochondrial iron accumulation. Iron accumulation mediated by divalent metal transporter 1 (DMT1) plays a key role in N-methyl-D-aspartate neurotoxicity. This study aims to determine whether peroxynitrite contributes to remifentanil-induced postoperative hyperalgesia via DMT1-mediated iron accumulation. METHODS: Behavior testing was performed in rat model at different time points. Three-nitrotyrosine, nitrated manganese superoxide dismutase, and DMT1 with/without iron-responsive element [DMT1(+)IRE and DMT1(-)IRE] in spinal cord were detected by Western blot and immunohistochemistry. Spinal iron concentration was measured using the Perl stain and atomic absorption spectrophotometer. Hydrogen-rich saline imparting selectivity for peroxynitrite decomposition and iron chelator was applied in mechanistic study on the roles of peroxynitrite and iron, as well as the prevention of hyperalgesia. RESULTS: Remifentanil induced thermal and mechanical hyperalgesia at postoperative 48 h. Compared with control, there were higher levels of 3-nitrotyrosine (mean ± SD, hyperalgesia vs. control, 1.22 ± 0.18 vs. 0.25 ± 0.05, n = 4), nitrated manganese superoxide dismutase (1.01 ± 0.1 vs. 0.19 ± 0.03, n = 4), DMT1(-)IRE (1.42 ± 0.19 vs. 0.33 ± 0.06, n = 4), and iron concentration (12.87 ± 1.14 vs. 5.26 ± 0.61 µg/g, n = 6) in remifentanil-induced postoperative hyperalgesia, while DMT1(+)IRE was unaffected. Eliminating peroxynitrite with hydrogen-rich saline protected against hyperalgesia and attenuated DMT1(-)IRE overexpression and iron accumulation. Iron chelator prevented hyperalgesia in a dose-dependent manner. CONCLUSIONS: Our study identifies that spinal peroxynitrite activates DMT1(-)IRE, leading to abnormal iron accumulation in remifentanil-induced postoperative hyperalgesia, while providing the rationale for the development of molecular hydrogen and "iron-targeted" therapies.

Glycogen synthase kinase-3ß inhibition prevents remifentanil-induced postoperative hyperalgesia via regulating the expression and function of AMPA receptors.

BACKGROUND: Many studies have confirmed that brief remifentanil exposure can enhance pain sensitivity. We previously reported that activation of glycogen synthase kinase-3ß (GSK-3ß) contributes to remifentanil-induced hyperalgesia via regulating N-methyl-D-aspartate receptor plasticity in the spinal dorsal horn. In this study, we demonstrated that GSK-3ß inhibition prevented remifentanil-induced postoperative hyperalgesia via regulating α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) expression and function in the spinal dorsal horn. METHODS: Using a rat model of remifentanil-induced incision hyperalgesia, mechanical and thermal pain was tested 1 day before infusion and 2 hours, 6 hours, 1 day, 2 days, 3 days, 5 days, and 7 days after infusion. Western blot analysis was used to detect AMPAR subunit (GluR1 and GluR2) trafficking, AMPAR phosphorylation status, and GSK-3ß activity in the spinal dorsal horn. Furthermore, whole-cell patch-clamp recording was used to analyze the effect of GSK-3ß inhibition on AMPAR-induced current in the spinal dorsal horn. RESULTS: Membrane AMPAR subunit GluR1 was upregulated in the spinal cord in remifentanil-induced postoperative hyperalgesia rats (275 ± 36.54 [mean ± SD] vs 100 ± 9.53, P = 0.0009). Selective GSK-3ß inhibitors, LiCl and TDZD, treatment ameliorates remifentanil-induced postoperative hyperalgesia, and this was associated with the downregulated GluR1 subunit in the membrane fraction (254 ± 23.51 vs 119 ± 14.74, P = 0.0027; 254 ± 23.51 vs 124 ± 9.35, P = 0.0032). Moreover, remifentanil incubation increased the amplitude and the frequency of AMPAR-induced current in dorsal horn neurons (61.09 ± 9.34 pA vs 32.56 ± 6.44 pA, P = 0.0009; 118.32 ± 20.33 milliseconds vs 643.67 ± 43.29 milliseconds, P = 0.0002), which was prevented with the application of LiCl and TDZD, respectively. Remifentanil-induced postoperative pain induced an increase in pGluR1 Ser845 and Rab5, which was prevented with the application of LiCl and TDZD. CONCLUSIONS: These results indicate that amelioration of remifentanil-induced postoperative hyperalgesia by GSK-3ß inhibition is attributed to downregulated AMPAR GluR1 expression in the membrane fraction and inhibition of AMPAR function via altering pGluR1 and Rab5 expression in the spinal dorsal horn.

LCN2 and ELANE overexpression induces sepsis.

Sepsis is a syndrome characterized by a systemic inflammatory response due to the invasion of pathogenic microorganisms. The relationship between Lipocalin-2 (LCN2), elastase, neutrophil expressed (ELANE) and sepsis remains unclear. The sepsis datasets GSE137340 and GSE154918 profiles were downloaded from gene expression omnibus generated from GPL10558. Batch normalization, differentially expressed Genes (DEGs) screening, weighted gene co-expression network analysis (WGCNA), functional enrichment analysis, Gene Set Enrichment Analysis (GSEA), immune infiltration analysis, construction and analysis of protein-protein interaction (PPI) networks, Comparative Toxicogenomics Database (CTD) analysis were performed. Gene expression heatmaps were generated. TargetScan was used to screen miRNAs of DEGs. 328 DEGs were identified. According to Gene Ontology (GO), in the Biological Process analysis, they were mainly enriched in immune response, apoptosis, inflammatory response, and immune response regulation signaling pathways. In cellular component analysis, they were mainly enriched in vesicles, cytoplasmic vesicles, and secretory granules. In Molecular Function analysis, they were mainly concentrated in hemoglobin binding, Toll-like receptor binding, immunoglobulin binding, and RAGE receptor binding. In Kyoto Encyclopedia of Genes and Genomes (KEGG), they were mainly enriched in NOD-like receptor signaling pathway, Toll-like receptor signaling pathway, TNF signaling pathway, P53 signaling pathway, and legionellosis. Seventeen modules were generated. The PPI network identified 4 core genes (MPO, ELANE, CTSG, LCN2). Gene expression heatmaps revealed that core genes (MPO, ELANE, CTSG, LCN2) were highly expressed in sepsis samples. CTD analysis found that MPO, ELANE, CTSG and LCN2 were associated with sepsis, peritonitis, meningitis, pneumonia, infection, and inflammation. LCN2 and ELANE are highly expressed in sepsis and may serve as molecular targets.

Efficacy and safety of ciprofol for sedation in outpatient gynecological procedures: a phase III multicenter randomized trial.

Objective: Ciprofol (also known as cipepofol and HSK3486), is a compound similar to propofol in chemical structure and hypnotic effect. Herein we evaluated the efficacy and safety of ciprofol for sedation in outpatient gynecological procedures. Methods: This phase III multicenter randomized trial with a non-inferiority design was conducted in nine tertiary hospitals. We enrolled 135 women aged 18-65 years who were scheduled for ambulatory gynecological procedures. Patients were randomly assigned to receive either ciprofol (0.4 mg/kg for induction and 0.2 mg/kg for maintenance) or propofol (2.0 mg/kg for induction and 1.0 mg/kg for maintenance) sedation in a 2:1 ratio. Patients and investigators for data collection and outcome assessment were blinded to study group assignments. The primary outcome was the success rate of sedation, defined as completion of procedure without remedial anesthetics. The non-inferiority margin was set at -8%. Secondary outcomes included time to successful induction, time to full awake, time to meet discharge criteria, and satisfaction with sedation assessed by patients and doctors. We also monitored occurrence of adverse events and injection pain. Results: A total of 135 patients were enrolled; 134 patients (90 patients received ciprofol sedation and 44 patients propofol sedation) were included in final intention-to-treat analysis. The success rates were both 100% in the two groups (rate difference, 0.0%; 95% CI, -4.1 to 8.0%), i.e., ciprofol was non-inferior to propofol. When compared with propofol sedation, patients given ciprofol required more time to reach successful induction (median difference [MD], 2 s; 95% CI, 1 to 7; p < 0.001), and required more time to reach full awake (MD, 2.3 min; 95% CI, 1.4 to 3.1; p < 0.001) and discharge criteria (MD, 2.3 min; 95% CI, 1.5 to 3.2; p < 0.001). Fewer patients in the ciprofol group were dissatisfied with sedation (relative risk, 0.21; 95% CI, 0.06 to 0.77; p = 0.024). Patients given ciprofol sedation had lower incidences of treat-emergent adverse events (34.4% [31/90] vs. 79.5% [35/44]; p < 0.001) and injection pain (6.7% [6/90] vs. 61.4% [27/44]; p < 0.001). Conclusion: Ciprofol for sedation in ambulatory gynecological procedures was non-inferior to propofol, with less adverse events and injection pain. Clinical trial registration: ClinicalTrials.gov, identifier NCT04958746.

Glycogen synthase kinase-3ß contributes to remifentanil-induced postoperative hyperalgesia via regulating N-methyl-D-aspartate receptor trafficking.

BACKGROUND: Although remifentanil provides perfect analgesia during surgery, postoperative hyperalgesia after remifentanil administration might be a challenge to anesthesiologists. The trafficking and activation of N-methyl-D-aspartate (NMDA) receptors have a pivotal role in the development and maintenance of remifentanil-induced postoperative hyperalgesia. However, the underlying mechanisms of hyperalgesia are poorly elucidated. We designed the present study to examine the hypothesis that glycogen synthase kinase (GSK)-3ß could contribute to remifentanil-induced postoperative hyperalgesia via regulating NMDA receptor trafficking in the spinal cord. METHODS: Using a rat model of remifentanil-induced postoperative hyperalgesia, we first tested thermal and mechanical hyperalgesia at baseline (24 hours before incision) and 2, 6, 24, and 48 hours after remifentanil infusion. GSK-3ß mRNA and protein expression and NMDA receptor subunits (NR1, NR2A, and NR2B) trafficking in the spinal cord L4-L6 segments were then measured using real-time polymerase chain reaction and Western blot analysis. Furthermore, we investigated the effects of TDZD-8, a selective GSK-3ß inhibitor, on remifentanil-induced postoperative hyperalgesia and NMDA receptor subunits trafficking. RESULTS: Remifentanil induced significant postoperative hyperalgesia, as indicated by increased paw withdrawal latencies and thresholds to thermal and mechanical stimulation, which were markedly improved by pretreatment with TDZD-8. Moreover, remifentanil infusion increased the expression of GSK-3ß mRNA and protein as well as the GSK-3ß activity in the spinal cord. More importantly, intraoperative infusion of remifentanil increased NMDA receptor subunits (NR1 and NR2B) trafficking from the intracellular pool to surface pool in the spinal cord, which was significantly attenuated by TDZD-8. CONCLUSION: The above results suggest that activation of GSK-3ß contributes to remifentanil-induced postoperative hyperalgesia via regulating NMDA receptor subunits (NR1 and NR2B) trafficking in the spinal cord. Inhibition of GSK-3ß may be an effective novel option for the treatment of remifentanil-induced postoperative hyperalgesia.

[Regulative effects of hydrogen-rich medium on monocytic adhesion and vascular endothelial permeability].

OBJECTIVE: To explore the regulative effects of hydrogen-rich medium on lipopolysaccharide (LPS)-induced monocytes adhesion to human umbilical vein endothelial cells (HUVEC) and vascular endothelial permeability in vitro. METHODS: Endothelial cells were seeded in 6-well plates and randomly divided into 4 groups (n = 42 each):control (A), hydrogen-rich medium (B), LPS (C) and LPS+hydrogen-rich medium (D). Cells were cultured in plain culture medium in groups A and C or in hydrogen-saturated culture medium in groups B and D.LPS 1 µg/ml was added into groups C and D.When forming a monolayer, monocytes were added into each group after 6, 12 and 24 h respectively. After a 90-minute co-culturing, adhesion status was detected by Wright-Giemsa stain.Supernatants were collected to detect the concentrations of vascular cell adhesion molecule-1 (VCAM-1) and E-selectin by enzyme-linked immunosorbent assay (ELISA). The expression of VE-cadherin was measured by Western blot. Cells were stained with immunofluorescence to show the distribution of VE-cadherin after a 24-hour incubation. RESULTS: Compared with group A, the adhesion of monocytes to endothelial cells increased (P < 0.05) in group C, the levels of E-selectin and VCAM-1 became elevated (P < 0.05) while the expression of VE-cadherin decreased significantly (P < 0.05). Compared with group C, adhesion decreased in group D (P < 0.05), the levels of E-selectin and VCAM-1 decreased (P < 0.05) while there was an increased expression of VE-cadherin (P < 0.05). Three timepoints showed the same tendency. The results of 24 h fluorescence indicated that, compared with group A, VE-cadherin was incomplete in cell-cell connections in group C.However it was complete and well-distributed in group D versus group C. CONCLUSION: Hydrogen-rich medium may reduce the LPS-induced release of adhesion molecules, lessen monocytic adhesion to HUVEC and regulate the expression of VE-cadherin to protect vascular permeability.

The m6A reader YTHDC2 promotes SIRT3 expression by reducing the stabilization of KDM5B to improve mitochondrial metabolic reprogramming in diabetic peripheral neuropathy.

AIMS: Diabetic peripheral neuropathy (DPN) is a common diabetic complication. Aberrant mitochondrial function causes neurodegeneration under hyperglycemia-induced metabolic stress, which in turn results in DPN progression. m6A and m6A reader (YTHDC2) are closely related to diabetes and diabetes complications, while the role of YTHDC2 in regulating mitochondrial metabolism in DPN needs to be further probed. METHODS: For HG treatment, Schwann cells (RSC96) were subjected to D-glucose for 72 h. db/db mice were used as the diabetic mouse model. Me-RIP assay was performed to evaluate KDM5B m6A level. RNA degradation assay was conducted to examine KDM5B mRNA stability. In addition, OCR and ECAR were examined by XF96 Analyzer. Moreover, the content of ATP and PDH activity in RSC96 cells were detected using kits, and the level of ROS was detected using MitoSOX staining. RIP, RNA pull-down and dual-luciferase reporter gene assays were carried out to verify the binding relationships between YTHDC2, KDM5B and SIRT3. RESULTS: We first observed that KDM5B expression and KDM5B mRNA stabilization were significantly increased in DPN. The m6A reader YTHDC2 was lowly expressed in DPN. Meanwhile, YTHDC2 over expression decreased KDM5B mRNA stability in an m6A-dependent manner. Our results also revealed that YTHDC2 overexpression resulted in reduced ROS level and increased ATP level, PDH activity, OCR and ECAR in HG-treated Schwann cells, while these effects were reversed by KDM5B overexpression. Additionally, SIRT3 served as the target of YTHDC2/KDM5B axis in regulating mitochondrial metabolism in DPN. CONCLUSIONS: Taken together, YTHDC2 promoted SIRT3 expression by reducing the stabilization of KDM5B to improve mitochondrial metabolic reprogramming in DPN.

[Changes of glycogen synthase kinase-3ß and its phosphorylation in spinal cord neurons in rats with incisional pain-remifentanil-induced hyperalgesia].

OBJECTIVE: To investigate the change in glycogen synthase kinase-3ß (GSK-3ß) in spinal cord neurons in rats with incisional pain (IP)-remifentanil-induced hyperalgesia. METHODS: 32 SD male rats (240 - 260 g) were randomly divided into 4 groups (n = 8 each): group R, group I, group R + I and group C. IP was established as Brennan's description. Paw withdrawal threshold (PWT) and paw withdrawal latency (PWL) were measured 24h before anesthesia and 2, 6, 24, 48 h after anesthesia. The rats were sacrificed after the last threshold measurement. The expressions of GSK-3ß mRNA in rats' spinal cord neurons were determined by real-time PCR. The expressions of GSK-3ß and pGSK-3ß in rats' spinal cord neurons were determined by Western blot. RESULTS: Remifentanil-induced hyperalgesia developed in group R, I and R + I. The expression of GSK-3ß mRNA and the expression of GSK-3ß in rats' spinal cord neurons were highest in group R + I. In addition, the ratio of pGSK-3ß/GSK-3ß was smallest in group R + I. CONCLUSION: These data indicate that the increased GSK-3ß activity in rats spinal cord neurons is involved in remifentanil-induced hyperalgesia.

[Effects of intrathecal injection of ginsenoside Rg1 on the level of glutamate transporter in the arthritis rats with chronic morphine tolerance].

OBJECTIVE: To investigate the effects of intrathecal injection of ginsenoside Rg1 at different doses on the changes of the behavior and the expressions of excitatory amino-acid transporter 1 (EAAT1), i. e., glutamate-aspartate transporter (GLAST) in the spinal dorsal horn of the arthritis rats with chronic morphine tolerance, and further to explore its mechanisms for morphine tolerance. METHODS: After successful intrathecal injection, an adjuvant arthritis model was established in 36 healthy male SD rats. They were randomly divided into 6 groups, 6 in each group. They were intrathecally injected with 10 microL normal saline (Group NS), 10 microg morphine (Group M), 10 microg morphine + 50 microg ginsenoside Rg1 (Group MG50), 10 microg morphine +100 microg ginsenoside Rg1 (Group MG100), 10 microg morphine + 200 microg ginsenoside Rg1 (Group MG200), and 100 microg ginsenoside Rg1 (Group G100), respectively. The normal saline and morphine were intrathecally injected twice daily, while ginsenoside Rg1 at different doses was intrathecally injected once daily, for 7 successive days. Fifty percent mechanical paw withdrawal threshold (PWT) was dynamically detected to evaluate their behaviors. The rats were sacrificed on day 7 after medication. The L3-L5 segment of the spinal cord was isolated for determining the expression of GLAST in the spinal dorsal horn using immunofluorescence staining. RESULTS: The PWT of Group M was significantly higher than that of Group NS on the 1st and 3rd day after medication (P < 0.05). But it was gradually shortened along with the increasing days of medication. There was no statistical difference between Group M and Group NS on the 7th day (P > 0.05), indicating the formation of morphine tolerance. The PWT of Group MG100 also showed a decreasing tendency, but obviously slower than that of Group M (P < 0.05). The PWT of Group G100 was higher than that of Group NS (P < 0.05). Compared with Group NS, the expression of GLAST in the spinal dorsal horn of rats in Group M was down-regulated (P < 0.01). Compared with Group M, the expression of GLAST in the spinal dorsal horn of rats in Group MG100 and Group G100 was up-regulated (P < 0.05). CONCLUSIONS: Single application of ginsenoside Rg1 showed mild antinociceptive effect in adjuvant-induced arthritis rats. Intrathecal injection of 100 microg ginsenoside Rg1 could attenuate the formation of morphine tolerance. Its mechanisms might be correlated with up-regulating of the expression of GLAST.

Role of TRPM8 in dorsal root ganglion in nerve injury-induced chronic pain.

BACKGROUND: Chronic neuropathic pain is an intractable pain with few effective treatments. Moderate cold stimulation can relieve pain, and this may be a novel train of thought for exploring new methods of analgesia. Transient receptor potential melastatin 8 (TRPM8) ion channel has been proposed to be an important molecular sensor for cold. Here we investigate the role of TRPM8 in the mechanism of chronic neuropathic pain using a rat model of chronic constriction injury (CCI) to the sciatic nerve. RESULTS: Mechanical allodynia, cold and thermal hyperalgesia of CCI rats began on the 4th day following surgery and maintained at the peak during the period from the 10th to 14th day after operation. The level of TRPM8 protein in L5 dorsal root ganglion (DRG) ipsilateral to nerve injury was significantly increased on the 4th day after CCI, and reached the peak on the 10th day, and remained elevated on the 14th day following CCI. This time course of the alteration of TRPM8 expression was consistent with that of CCI-induced hyperalgesic response of the operated hind paw. Besides, activation of cold receptor TRPM8 of CCI rats by intrathecal application of menthol resulted in the inhibition of mechanical allodynia and thermal hyperalgesia and the enhancement of cold hyperalgesia. In contrast, downregulation of TRPM8 protein in ipsilateral L5 DRG of CCI rats by intrathecal TRPM8 antisense oligonucleotide attenuated cold hyperalgesia, but it had no effect on CCI-induced mechanical allodynia and thermal hyperalgesia. CONCLUSIONS: TRPM8 may play different roles in mechanical allodynia, cold and thermal hyperalgesia that develop after nerve injury, and it is a very promising research direction for the development of new therapies for chronic neuroapthic pain.

[Participation of glucocorticoid receptors in morphine tolerance development through the signal pathway of extracellular signal-regulated kinase].

OBJECTIVE: To investigate the mechanism of glucocorticoid receptors (GR) participating in morphine tolerance development via the extracellular signal-regulated kinase (ERK) signal pathway. METHODS: Forty healthy male SD rats were implanted with intrathecal catheters and then randomized into 4 groups: Group C received an intrathecal injection of 10 µl saline, Group M 10 µg morphine, Group MR 10 µg morphine followed by 2 µg GR antagonist RU38486 and Group MD 10 µg morphine followed by 4 µg GR agonist dexamethasone (DEX) respectively. Each intrathecal drug was administered twice daily for 7 days. Tail-flick test was employed to evaluate the thermal hyperalgesia. After tail-flick test at Day 8, the lumbar intamescentias were isolated by Western blot to examine the protein expressions of Mu opioid receptor (MOR), GR and pERK. And terminal deoxynucleotidyl transferase mediated X-dUTP nick end labeling (TUNEL) stain was performed. RESULTS: DEX and RU38486 enhanced and inhibited morphine induced hyperalgesia to heat respectively. Compared with Group M (count of spinal dorsal horn apoptotic cells 5.4 ± 1.1, protein expression: MOR 37 ± 5, GR 20 ± 6, pERK(1) 39 ± 4, pERK(2) 41 ± 5), apoptotic cells decreased in Group MR (3.2 ± 0.4) (P < 0.01) and increased in Group MD (16.0 ± 1.6) (P < 0.01); the protein expressions of MOR (28 ± 5), GR (12 ± 6), pERK(1)(33 ± 4) and pERK(2)(34 ± 5) were down-regulated in Group MR (P < 0.01) while up-regulated in Group MD (55 ± 6, 28 ± 9, 49 ± 6, 59 ± 5) (P < 0.01). CONCLUSION: The activity of glucocorticoid receptors affects the morphine-induced spinal neural apoptosis and the expression of spinal pERK in morphine tolerance.

Hydrogen alleviated organ injury and dysfunction in sepsis: The role of cross-talk between autophagy and endoplasmic reticulum stress: Experimental research.

AIMS: Sepsis is defined as a life-threatening organ dysfunction that is caused by a dysregulated host response to infection. Although much progress has been made in understanding the pathophysiology of sepsis, further discussion and study of the detailed therapeutic mechanisms are needed. Autophagy and endoplasmic reticulum stress are two pathways of the complicated regulatory network of sepsis. Herein, we focus on the cellular mechanism in which autophagy and endoplasmic reticulum stress participate in hydrogen (H2)-protected sepsis-induced organ injury. MATERIALS AND METHODS: Male C57BL/6 mice were randomly divided into the following groups: control group, cecal ligation puncture (CLP) group, CLP + tunicamycin(TM) group, CLP + 4-phenyl butyric acid (4-PBA) group, CLP + rapamycin (Rap) group, CLP + 3-methyladenine (3-MA) group, CLP + H2 group, CLP + H2 + 3-MA group, and CLP + H2 + TM group. After the experiment was completed, autophagosome was detected by transmission electron microscopy; protein PKR-like ER kinase (PERK), p-PERK, Eukaryotic translation initiation factor-2α (eIF2α), p-eIF2α, inositol-requiring enzyme1α(IRE1α), C/EBP homologous protein(CHOP), activating transcription factor(ATF), XBP-1, microtubule-associated protein 1 light(LC3), Beclin1, PTEN-induced putative kinase 1(PINK1), Parkin, and p65 subunit of Nuclear factor kappa B(NF-κb) were measured by Western blot; myeloperoxidase(MPO) activity in lung, bronchoalveolar lavage(BAL) total protein, lung wet-to-dry(W/D) ratio, serum biochemical indicators, 7-day survival rate, and pathological injury scores of lung, liver, and kidney were tested; and cytokines tumor necrosis factor-α(TNF-α), Interleukin(IL)-1ß, and IL-6 and high mobility group box protein (HMGB)1 were detected by enzyme-linked immunosorbent assay(ELISA). RESULTS: We demonstrated that sepsis induced endoplasmic reticulum stress. Moreover, it was found that an increase in endoplasmic reticulum impaired autophagy activity in sepsis, and the absence of endoplasmic reticulum stress attenuated tissue histological injury and dysfunction of lung, liver, and kidney in septic mice. Intriguingly, hydrogen alleviated the endoplasmic reticulum stress via the autophagy pathway and also mitigated inflammation and organ injury. CONCLUSION: Hydrogen provided protection from organ injury induced by sepsis via autophagy activation and endoplasmic reticulum stress pathway inactivation.

[Propofol provides ischemic postconditioning on myocardial ischemia-reperfusion injury in rats].

OBJECTIVE: To investigate whether the infusion of propofol during early reperfusion provides ischemic postconditioning (I-postC) on myocardial ischemia-reperfusion injury in rats. METHODS: Sixty adult rats were randomly divided into 5 groups (n = 12 each): sham operation (group S); normal saline (group C); propofol 1 mg/kg (group P1); propofol 2 mg/kg (group P2); propofol 5 mg/kg (group P3). The left anterior descending coronary artery (LAD) was occluded for 60 min and reperfused for 120 min. Normal saline, propofol 1 mg/kg, 2 mg/kg or 5 mg/kg (propofol diluted to 2.5 ml with normal saline equally) were intravenously infused 3 min before reperfusion until 5 min after reperfusion. The heart were obtained for determination of (1) the size of area at risk and infarct size (Evans Blue and TTC staining); (2) expression of Caspase-3 (immunohistochemistry staining); (3) percentage of apoptotic cardiomyocytes (flow cytometry); (4) levels of phosphorylated Akt (Western blot). RESULTS: Compared with group C [size of area at risk (41.5 +/- 1.0)%, infarct size (45.5 +/- 1.0)%, expression of caspase-3 (5.87 +/- 0.29), percentage of apoptotic cardiomyocytes (26.8 +/- 1.3)%, level of phosphorylated Akt (10.8 +/- 1.9)%], propofol 1 mg/kg and 2 mg/kg significantly reduced the size of area at risk and infarct size [size of area at risk (38.3 +/- 1.0)% and (37.3 +/- 1.2)%; infarct size (33.8 +/- 1.2)% and (30.2 +/- 1.7)%, P < 0.05], inhibited the expression of caspase-3 (1.50 +/- 0.36 and 1.48 +/- 0.30, P < 0.05), decreased the percentage of apoptotic cardiomyocytes [(16.3 +/- 1.2)% and (16.5 +/- 1.0)%, P < 0.05] and promoted the phosphorylation of Akt [(68.7 +/- 4.0)% and (58.3 +/- 2.8)%, P < 0.05]. CONCLUSION: Propofol 1 mg/kg and 2 mg/kg can provide I-postC to myocardial ischemia-reperfusion injury in rats by activation of Akt pathway.

Spinal glucocorticoid receptor­regulated chronic morphine tolerance may be through extracellular signal­regulated kinase 1/2.

Opioid use has been limited in the treatment of chronic pain due to their side effects, including analgesic tolerance. Previous studies demonstrated that glucocorticoid receptors (GRs) may be involved in the development of chronic morphine tolerance; however, the mechanism remains unknown. It was hypothesized that the expression of spinal phosphorylated mitogen­activated protein kinase [MAPK; phosphorylated extracellular signal­regulated kinase (ERK)] is regulated through the spinal GRs, following chronic treatment with morphine. In the first experiment, the experimental rats were randomly divided into four groups: Control, morphine, morphine+GR antagonist mifepristone (RU38486) and morphine+GR agonist dexamethasone (Dex). Each group was treated with continuous intrathecal (IT) injection of the drugs for 6 days. The expression of GRs and MAPK 3/1 (p­ERK 1/2) in the spinal dorsal horn was detected by western blot analysis and immunofluorescence staining. In the second experiment, the MAPK inhibitor PD98059 was added and the rats were randomly divided into four groups: Control, morphine, PD98059+morphine and PD98059+morphine+Dex. The continuous IT injection lasted for 7 days in each group. For all experiments, the tail flick test was conducted 30 min following administration every day to assess the thermal hyperalgesia of the rats. The experimental results demonstrated that there was a co­existence of GRs and p­ERK 1/2 in the spinal cord dorsal horn by double immunofluorescence staining. The GR antagonist RU38486 attenuated the morphine analgesia tolerance by inhibiting the expression of GR and increasing the expression of p­ERK. The MAPK inhibitor PD98059 increased the effect of morphine tolerance and prolonged the duration of morphine tolerance. The present results suggest that spinal GRs may serve an important role in the development of morphine tolerance through the ERK signaling pathway.

Prevention of Remifentanil Induced Postoperative Hyperalgesia by Dexmedetomidine via Regulating the Trafficking and Function of Spinal NMDA Receptors as well as PKC and CaMKII Level In Vivo and In Vitro.

Remifentanil-induced secondary hyperalgesia has been demonstrated in both animal experiments and clinical trials. Enhancement of N-methyl-D-aspartate (NMDA) receptor trafficking as well as protein kinase C (PKC) and calmodulin-dependent protein kinase II (CaMKII) have been reported to be involved in the induction and maintenance of central sensitization. In the current study, it was demonstrated that dexmedetomidine could prevent remifentanil-induced hyperalgesia (RIH) via regulating spinal NMDAR-PKC-Ca2+/ CaMKII pathway in vivo and in vitro. We firstly investigated the effect of dexmedetomidine, a highly selective α2-adrenergic receptor agonist, on mechanical and thermal hyperalgesia using a rat model of RIH. NMDA receptor subunits (NR1, NR2A and NR2B) expression and membrane trafficking as well as PKC and CaMKII expression in spinal cord L4-L5 segments were measured by Western blot analysis. The expression of NMDA receptor subunits (NR1, NR2A and NR2B) were also detected by immunohistochemistry. Further more, the effect of dexmedetomidine on NMDA receptor current amplitude and frequency in spinal cord slices were investigated by whole-cell patch-clamp recording. We found that remifentail infusion at 1.2 µg.kg-1.min-1 for 90 min caused mechanical and thermal hyperalgesia, up-regulated NMDA receptor subunits NR1 and NR2B expression in both membrane fraction and total lysate as well as increased PKC and CaMKII expression in spinal cord dorsal horn. Subcutaneously injection of dexmedetomidine at the dose of 50 µg/kg at 30 min before plantar incision significantly attenuated remifentanil-induced mechanical and thermal hyperalgesia from 2 h to 48 h after infusion, and this was associated with reversal of up-regulated NR1 and NR2B subunits in both membrane fraction and total lysate as well as increased PKC and CaMKII expression in spinal cord dorsal horn. Furthermore, remifentanil incubation increased amplitude and frequency of NMDA receptor-induced current in dorsal horn neurons, which was dose-dependently attenuated by dexmedetomidine. These results suggest that dexmedetomidine can significantly ameliorate RIH via modulating the expression, membrane trafficking and function of NMDA receptors as well as PKC and CaMKII level in spinal dorsal horn, which present useful insights into the mechanistic action of dexmedetomidine as a potential anti-hyperalgesic agents for treating RIH.

[Monocyte response and regulatory effect of emodin and shenmai injection on it in patients with severe sepsis].

OBJECTIVE: To investigate the impact of monocyte releasing tumor necrosis factor-alpha (TNF-alpha) and interleukin-10 (IL-10) stimulated by lipopolysaccharide (LPS) in severe sepsis (SS) patients, and the regulatory effect of emodin and Shenmai Injection (SMI) on monocyte response. METHODS: ocyte (PBMC) sampled from SS patients due to severe abdominal inflammation and healthy controls, PBMC were incubated with or without LPS, respectively. PBMC media pretreated with emodin and SMI, and then the levels of cytokine factors including TNF-alpha and IL-10 in supernatants were determined after stimulated with or without LPS in the two groups. Normal PBMC stimulated with LPS based on incubated with either normal serum or SS serum, and the levels of TNF-alpha and IL-10 in supernatant of normal PBMC and SS serum dealing with emodin or SMI after cultured and stimulated with LPS were determined, respectively. RESULTS: The levels of TNF-alpha and IL-10 were significantly higher in SS patients than those in the healthy adults. The contents of TNF-alpha and IL-10 increased in response to LPS in PBMC of healthy adults, and the excretion of TNF-alpha was significantly attenuated whereas IL-10 significantly increased in septic PBMC than basal content. Both of the two traditional Chinese medicines had significantly effect in stimulating PBMC secretion in healthy adults and SS patients. In normal PBMC, emodin attenuated TNF-alpha and IL-10 release in response to LPS, and SMI significantly inhibited TNF-alpha release. As to septic PBMC, emodin significantly stimulated TNF-alpha and IL-10 release and SMI significantly increased the concentration of TNF-alpha in the SS patients. Incubation of normal PBMC with septic serum attenuated TNF-alpha production, whereas increased IL-10 release. Emodin could significantly decrease the level of IL-10, and SMI recovered TNF-alphareleasing and had no effect on IL-10. CONCLUSION: The level of TNF-alpha significantly decreased accompanied with an anti-inflammatory cytokine IL-10 significantly increased of PBMC in SS patients. Monocyte exhibits the different response of inflammatory or anti-inflammatory factor which may be one of the reasons of imbalance of immune function in SS patients. Both of emodin and SMI may have regulatory effect on excretion of PBMC in SS patients, but they play a role in different ways.