Interaction of remimazolam benzenesulfonate and human serum albumin: a simulated physiological study.

Here, to elucidate the interaction mechanism and physicochemical properties of remimazolam and human serum albumin interactions, techniques such as fluorescence, circular dichroism (CD) spectroscopy, and isothermal titration calorimetry have been applied for study. The thermodynamic parameters at body temperature (ΔS = -207 J·mol-1 ·K-1 , ΔS = -9.76 × 104 J·mol-1 and ΔG = -3.34 × 104 J·mol-1 ; 310 K) manifests one strong binding site on the protein, which was modulated by van der Waals forces and hydrogen bonds. What is more, the results of CD, synchronous and three-dimensional fluorescence showed that remimazolam altered the microenvironment of the protein amino acid residues. A distance of 2.1 nm between the remimazolam and Trp shows the potential for resonance energy transfer. Furthermore, these results potentially provide information for illustrating the pharmacodynamics and toxicodynamics of remimazolam when it is applied clinically.

Ni/Ni3Al interface-dominated nanoindentation deformation and pop-in events.

Nickel-based single crystal alloys have excellent mechanical properties due to its unique two-phase structure and interface. Therefore, molecular dynamics methods were used to simulate nanoindentation and microstructural evolution. We found the indenter reaction force and hardness of the Ni3Al phase is the largest. The pop-in event in Ni3Al phase is more obvious than that in the Ni phase and Ni/Ni3Al phase. Because lots of dislocations in the Ni3Al phase break through the barrier of the interface and cut into the Ni phase, while dislocations in the Ni phase only slip inside the Ni phase. Moreover, we found that the position of the starting point of the adhesion force recovery is mainly related to the elastic recovery of the material. The stronger the elastic recovery of the phase, the smaller the depth value corresponding to the starting point of the recovery. We further studied the variation of potential energy with indentation depth and found that the change of wave trough of the load-displacement (P-h) curve is related to stacking fault energy. This study has important theoretical guiding significance for the in-depth understanding and engineering application of the mechanical properties of nickel-based single crystal alloys.

Sevoflurane prevents vulnerable plaque disruption in apolipoprotein E-knockout mice by increasing collagen deposition and inhibiting inflammation.

BACKGROUND: Sevoflurane may reduce the occurrence of major adverse cardiovascular events (MACCEs) in surgical patients, although the mechanisms are poorly understood. We hypothesised that sevoflurane stabilises atherosclerotic plaques by inhibiting inflammation and enhancing prolyl-4-hydroxylase α1 (P4Hα1), the rate-limiting subunit for the P4H enzyme essential for collagen synthesis. METHODS: We established a vulnerable arterial plaque model in apolipoprotein E-knockout mice (ApoE-/-) fed a high-fat diet that underwent daily restraint/noise stress, with/without a single prior exposure to sevoflurane for 6 h (1-3%; n=30 per group). In vitro, smooth muscle cells (SMCs) were incubated with tumour necrosis factor-alpha in the presence/absence of sevoflurane. Immunohistochemistry, immunoblots, and mRNA concentrations were used to quantify the effect of sevoflurane on plaque formation, expression of inflammatory cytokines, P4Hα1, and collagen subtypes in atherosclerotic plaques or isolated SMCs. RESULTS: In ApoE-/- mice, inhalation of sevoflurane 1-3% for 6 h reduced the aortic plaque size by 8-29% in a dose-dependent manner, compared with control mice that underwent restraint stress alone (P<0.05); this was associated with reduced macrophage infiltration and lower lipid concentrations in plaques. Sevoflurane reduced gene transcription and protein expression levels of pro-inflammatory cytokines (≥69-75%; P<0.05) and matrix metalloproteinases (≥39-65%; P<0.05) at both gene transcription and protein levels, compared with controls. Sevoflurane dose dependently increased Types I and III collagen deposition through enhanced protein expression of P4Hα1, both in vivo and in vitro (0.7-3.3-fold change; P<0.05). CONCLUSIONS: Sevoflurane dose dependently promotes plaque stabilisation and decreases the incidence of plaque disruption in ApoE-/- mice by increasing collagen deposition and inhibiting inflammation. These mechanisms may contribute to sevoflurane reducing MACCE.

Dexmedetomidine Post-Conditioning Alleviates Cerebral Ischemia-Reperfusion Injury in Rats by Inhibiting High Mobility Group Protein B1 Group (HMGB1)/Toll-Like Receptor 4 (TLR4)/Nuclear Factor kappa B (NF-κB) Signaling Pathway.

BACKGROUND Cerebral ischemia-reperfusion injury is a pivotal cause of deaths due to cerebrovascular accident. Increased research efforts are needed to reveal the mechanism underlying its aggravation or alleviation. In this study, the effects of dexmedetomidine post-conditioning on the HMGB1/TLR4/NF-kappaB signaling pathway in cerebral ischemia-reperfusion rats was explored. MATERIAL AND METHODS Ninety rats were randomly divided into 5 groups - a sham group (Sham), a model group (I/R), a dexmedetomidine post-conditioning group (Dex), a recombinant high mobility group protein B1 group (rHMGB1), and a recombinant HMGB1+dexmedetomidine post-conditioning group (rHMGB1+Dex) - with 18 rats in each group. Longa grading, wet-dry weighing, TTC staining, HE staining, and immunohistochemical staining were used to assess brain damage. ELISA, RT-PCR, and Western blot analyses were performed to assess expression of IL-1ß, TNF-alpha, IL-6, IL-8, HMGB1, TLR4, and NF-kappaB. RESULTS Compared with the I/R group, the neurological function score, brain water content, infarction area, and the number of COX-2- and IBA-1-positive cells in the Dex group were significantly lower, accompanied by downregulated expression of the HMGB1/TLR4/NF-kappaB pathway, alleviated inflammation, and oxidative stress injury in brain tissue. These trends were mostly reversed in the rHMGB1 group and rHMGB1+Dex group, but not in the Dex group. Furthermore, when compared to the Dex group, there were significant increases of H2O2, MDA, NO, IL-1ß, TNF-alpha, IL-6, IL-8, HMGB1, TLR4, and p-P65 in the rHMGB1 group and rHMGB1+Dex group, in which a significant decrease of T-AOC, SOD, and p-IkappaBalpha was also detected. CONCLUSIONS Dexmedetomidine post-conditioning can alleviate cerebral ischemia-reperfusion injury in rats by inhibiting the HMGB1/TLR4/NF-kappaB signaling pathway.

Anesthetic Agents Isoflurane and Propofol Decrease Maximal Ca2+-Activated Force and Thus Contractility in the Failing Myocardium.

In the normal heart, frequently used anesthetics such as isoflurane and propofol can reduce inotropy. However, the impact of these agents on the failing myocardium is unclear. Here, we examined whether and how isoflurane and propofol influence cardiac contractility in intact cardiac muscles from rats treated with monocrotaline to induce heart failure. We measured force and intracellular Ca2+ ([Ca2 +]i) in trabeculae from the right ventricles of the rats in the absence or presence of propofol or isoflurane. At low to moderate concentrations, both propofol and isoflurane dose-dependently depressed cardiac force generation in failing trabeculae without altering [Ca2+]i At high doses, propofol (but not isoflurane) also decreased amplitude of [Ca2+]i transients. During steady-state activation, both propofol and isoflurane impaired maximal Ca2+-activated force (Fmax) while increasing the amount of [Ca2+]i required for 50% of maximal activation (Ca50). These events occurred without apparent change in the Hill coefficient, suggesting no impairment of cooperativity. Exposing these same muscles to the anesthetics after fiber skinning resulted in a similar decrement in Fmax and rise in Ca50 but no change in the myofibrillar ATPase-Ca2+ relationship. Thus, our study demonstrates that challenging the failing myocardium with commonly used anesthetic agents such as propofol and isoflurane leads to reduced force development as a result of lowered myofilament responsiveness to Ca2+ SIGNIFICANCE STATEMENT: Commonly used anesthetics such as isoflurane and propofol can impair myocardial contractility in subjects with heart failure by lowering myofilament responsiveness to Ca2+. High doses of propofol can also reduce the overall amplitude of the intracellular Ca2+ transient. These findings may have important implications for the safety and quality of intra- and perioperative care of patients with heart failure and other cardiac disorders.

Effects of sevoflurane on reproductive function of male rats and its main mechanism of action.

Objective: To study the effects of sevoflurane on reproductive function and its main mechanism of action in male rats.Materials and methods: Forty adult male Sprague-Dawley rats were divided into 4 groups and exposed to 0, 50, 300 and 1800 ppm of sevoflurane, respectively. After 15 days, the serum levels of sex hormones and inflammatory factors were detected using enzyme-linked immunosorbent assay. Left testis was taken for conventional histopathological examination and TUNEL staining. Right testis was used for sperm production and daily sperm count were evaluated daily. Johnsen score was used to categorize the spermatogenesis. The expression of related genes in the hypothalamic-pituitary-gonadal axis were analyzed by quantitative real time polymerase chain reaction (qRT-PCR).Results: Exposure to sevoflurane increased the levels of serum follicle-stimulating hormone (FSH), luteinizing hormone (LH), tumor necrosis factor-α (TNF-α), and monocyte chemoattractant protein 1 (MCP-1), decreased the content of serum testosterone (T), reduced the concentration of testicular sperm, the production of daily sperm and Johnsen score, and damaged vas deferens in a dose dependent manner. In addition, chronic exposure to sevoflurane down-regulated transcription of gonadotropin-releasing hormone (GnRH) and kisspeptin (Kiss)-1 as well as its receptor GPR54 in hypothalamus, attenuated GnRH receptor and LH-ß mRNA levels, but increased FSH-ß mRNA in pituitary gland, and enhanced mRNA of LH receptor and FSH receptor, but decreased INH-α and INH-ßA mRNA levels in testes.Discussion and conclusions: Sevoflurane induces disorders of spermatogenesis and causes testicular injury. The underlying mechanism may be related to the imbalance of sex hormones in the hypothalamic-pituitary-gonadal axis.

Pharmacological analysis of dexmedetomidine hydrochloride in pediatric anesthesia during magnetic resonance imaging.

Dexmendetomidine hydrochloride (DEX) is a new common adrenergic receptor agonist, which not only keeps children calm but also has analgesic effect. Dexmedetomidine hydrochloride will enable children to maintain the natural non-REM sleep, which can be stimulated sedation or language arousal. The aim of this study is to observe the sedative effect and adverse drug reactions of dexmedetomidine hydrochloride injection and propofol injection in MRI examination. In this study, no children in the experimental group were required to add sedative drugs, and 2 cases in the control group were treated with sedative drugs. In experimental group, it used dexmedetomidine hydrochloride as (1.64±0.91) g/kg; in control group, dosage of narcotic drugs as (5.26±1.82) g/kg, and the total complication rate of the children in the experimental group was lower than that of the control group (P<0.05). After returning to the ward, the doses of phenobarbital sedation were dexmedetomidine group (4.28±1.53) mg/kg and propofol group (6.40±1.71) mg/kg. There was significant difference between the two groups. The total complication rate in the experimental group was lower than that in the control group (P<0.05). The quality of MRI in the test group was significantly higher than that in the control group, which showed that dexmedetomidine hydrochloride could provide a satisfactory sedative effect in the MRI examination of children. To sum up, dexmedetomidine hydrochloride is a wide range of clinical applications. It is an effective drug for the maintenance of sedation in clinical disease treatment. It is flexible in the way of administration and with less adverse reactions. It is suitable for popularization and application in clinical practice.

Molecular mechanism of anesthetic-induced depression of myocardial contraction.

Isoflurane and propofol are known to depress cardiac contraction, but the molecular mechanisms involved are not known. In this study, we determined whether decreasing myofilament Ca(2+) responsiveness underlies anesthesia-induced depression of contraction and uncovered the molecular targets of isoflurane and propofol. Force and intracellular Ca(2+) ([Ca(2+)]i) were measured in rat trabeculae superfused with Krebs-Henseleit solution, with or without propofol or isoflurane. Photoaffinity labeling of myofilament proteins with meta-Azi-propofol (AziPm) and Azi-isoflurane (Azi-iso) and molecular docking were also used. Both propofol and isoflurane dose dependently depressed force from low doses (propofol, 27 ± 6 µM; isoflurane, 1.0 ± 0.1%) to moderate doses (propofol, 87 ± 4 µM; isoflurane, 3.0 ± 0.25%), without significant alteration [Ca(2+)]i During steady-state activations in both intact and skinned preparations, propofol and isoflurane depressed maximum Ca(2+)-activated force and increased the [Ca(2+)]i required for 50% of activation. Myofibrils photolabeled with AziPm and Azi-iso identified myosin, actin, and myosin light chain as targets of the anesthetics. Several adducted residues in those proteins were located in conformationally sensitive regions that underlie contractile function. Thus, propofol and isoflurane decrease force development by directly depressing myofilament Ca(2+) responsiveness and have binding sites in key regions for contraction in both actin and myosin.-Meng, T., Bu, W., Ren, X., Chen, X., Yu, J., Eckenhoff, R. G., Gao, W. D. Molecular mechanism of anesthetic-induced depression of myocardial contraction.

Antinociceptive Effects of Isosakuranetin in a Rat Model of Peripheral Neuropathy.

Chronic pain remains a challenging clinical reality, yet currently available analgesics are insufficient to meet clinical needs. Increasing attention has been paid to bioactive compounds from natural plants, which may be efficacious against pain. This study examined the antinociceptive effects of isosakuranetin, a plant-derived transient receptor potential melastatin 3 blocker, in a rat model of peripheral neuropathy. Adult male Sprague-Dawley rats were first allowed to go through the chronic constriction injury surgery to develop neuropathic pain. They were then treated with isosakuranetin (1.5, 3, or 6 mg/kg) intraperitoneally and the effects on mechanical, thermal, and cold hyperalgesia were assessed using the von Frey filament test, Hargreaves' plantar test, and cold plate test, respectively. Isosakuranetin dose-dependently alleviated mechanical, thermal, and cold hyperalgesia and the antinociceptive potency was similar across the assays. In the rotarod test, isosakuranetin did not significantly affect motor performance within the doses tested, confirming the antinociceptive specificity. In summary, these findings suggest that isosakuranetin may be useful in treating neuropathic pain and deserves further investigation.

Dose-response studies of Ropivacaine in blood flow of upper extremity after supraclavicular block: a double-blind randomized controlled study.

BACKGROUND: The sympathetic block of upper limb leading to increased blood flow has important clinical implication in microvascular surgery. However, little is known regarding the relationship between concentration of local anesthetic and blood flow of upper limb. The aim of this dose-response study was to determine the ED50 and ED95 of ropivacaine in blood flow after supraclavicular block (SB). METHODS: Patients undergoing upper limb surgery and supraclavicular block were randomly assigned to receive 30ml ropivacaine in concentrations of 0.125%(A Group), 0.2%(B Group), 0.25%(C Group), 0.375%(D Group), 0.5%(E Group), or 0.75%(F Group) (n=13 per group). All patients received supraclavicular block (SB). Time average maximum velocity (TAMAX), cross-sectional area (CSA) of brachial artery and skin temperatures (Ts) were measured repeatedly at the same marked points, they were taken at baseline (before block, t0) and at 30min after SB (t1). Blood flow(BF) = TAMAX× CSA×60 sec.. Relative blood flow (ΔBF) = BFt1/ BFt0. Success of SB was assessed simultaneously. Supplementary anesthesia and other adverse events (AE) were recorded. RESULTS: Significant increase in TAMAX, CSA, BF and Ts were seen in all concentration groups at t1 comparing with t0 (P<0.001). There was an upward trend of TAMAX, CSA, BF with the increasing concentration of ropivacaine except Ts. There was no significant different of Ts at t1 among different concentration group. The dose-response formula of ropivacaine on ΔBF was Y=1+3.188/(1+10^((-2.451-X) × 1.730)) and ED50/ED95 (95%CI) were 0.35/1.94%(0.25-0.45/0.83-4.52), and R2 (coefficient of determination) =0.85. ED50/ED95 (95%CI) values of sensory block were 0.18/0.33% (0.15-0.21/0.27-0.51), R2=0.904. CONCLUSIONS: The dose-response curve between SB ropivacaine and the changes of BF was determined. The ED50/ED95 of ropivacaine of ΔBF are 0.35/1.94% (0.25-0.45/0.83-4.52). TAMAX, CSA and BF consistently increased with ropivacaine concentration. The maximal sympathetic block needs higher concentration than that complete sensation block needs which may benefit for microvascular surgery. TRIAL REGISTRATION: Clinicaltrials.gov NCT02139982 . Retrospectively registered (Date of registration: May, 2014).

Non-proton ligand-sensing domain of acid-sensing ion channel 3 is required for itch sensation.

Itch, the unpleasant sensation that evokes a desire to scratch, accompanies numerous skin and nervous system disorders. However, the molecular mechanisms of itch are unclear. Acid-sensing ion channel 3 (ASIC3) is a sensor of acidic and primary inflammatory pain. The whole-cell patch clamp technique was used to determine the effect of chloroquine (CQ) on ASICs currents in primary sensory neurons or the Chinese hamster ovary cells transfected with rat ASIC1a or ASIC3. Site-directed mutagenesis of plasmid was performed. Scratching behavior was evaluated by measuring the number of bouts during 30 min after injection. CQ, an anti-malarial drug defined as a histamine-independent pruritogen, selectively enhanced the sustained phase of ASIC3 current in a concentration-dependent manner either in ASIC3-transfected Chinese hamster ovary cells or in primary cultured rat dorsal root ganglion neurons. Further studies revealed that the effect of CQ on ASIC3 channels depends on the newly identified non-proton ligand-sensing domain. Importantly, CQ-evoked scratching behavior was largely alleviated by APETx2, a selective ASIC3 channel blocker. Like CQ, other compounds such as amiloride, 2-guanidine-4-methylquinazoline and neuropeptide FF, which have been previously reported to be non-proton ligands that activate ASIC3, undoubtedly evoked the scratching response. In conclusion, ASIC3, a proton-gated ion channel critical for pain sensation, also functions as an essential component of itch transduction.

The Effects of Two Anesthetics, Propofol and Sevoflurane, on Liver Ischemia/Reperfusion Injury.

BACKGROUND: Propofol and sevoflurane are widely used in clinical anesthesia, and both have been reported to exert a protective effect in organ ischemia/reperfusion (IR). This study aims to investigate and compare the effects of propofol and sevoflurane on liver ischemia/reperfusion and the precise molecular mechanism. METHODS AND MATERIALS: Rats were randomized into four groups: the sham group, I/R group, propofol treatment group (infused with 1% propofol at 500 µg· kg-1· min-1), and sevoflurane treatment group (infused with 3% (2 L/min) sevoflurane). The liver ischemia/reperfusion model was used to evaluate the hepatoprotective effect on ischemic injury. Liver enzyme leakage, liver cytokines and histopathological examination were used to evaluate the extent of hepatic ischemia/reperfusion injury. Oxidative stress was investigated by evaluating the levels of Malondialdehyde(MDA), Superoxide Dismutase(SOD) and NO. The terminal dexynucleotidyl transferase(TdT)-mediated dUTP nick end labeling (TUNEL) assay and western blot were applied to detect apoptosis in the ischemic liver tissue and its mechanism. RESULTS: Both propofol and sevoflurane attenuated the extent of hepatic ischemia/reperfusion injury which is evident from the hisopathological studies and alterations in liver enzymes such as AST and LDH by inhibiting Nuclear factor kappa B (NFx03BA;B) activation and subsequent alterations in inflammatory cytokines interleukin-1(IL-1), interleukin-6(IL-6), tumor necrosis factor-alpha (TNF-α) and increased IL10 release. Propofol exhibited a similar protective effect and a lower IL-1 release, while sevoflurane decreased TNF-α leakage more significantly. Meanwhile, oxidative stress was attenuated by reduced MDA and NO and elevated SOD release. The expression of antiapoptotic protein Bcl-2 and Bcl-xl were enhanced while that of apoptotic protein Bax and Bak were reduced by both propofol and sevoflurane to regulate hepatic apoptosis. In addition, propofol downregulated the phosphorylation of AKT and Bad protein, while sevoflurane downregulated the phosphorylation of p38. In addition, Both the treatments had no effect on the expression of AKT, Bad and p38. CONCLUSION: Both propofol and sevoflurane can protect the liver from ischemia/reperfusion injury by modulating the inflammatory responses reducing oxidative stress and liver apoptosis.

Effect of Oxycodone Combined With Dexmedetomidine for Intravenous Patient-Controlled Analgesia After Video-Assisted Thoracoscopic Lobectomy.

OBJECTIVE: To investigate the effect of the combination of oxycodone and dexmedetomidine for patient-controlled analgesia (PCA) after video-assisted thoracoscopic (VATS) lobectomy. DESIGN: A prospective, randomized, double-blind, controlled trial. SETTING: Shandong Cancer Hospital and Institute in Jinan, China. PARTICIPANTS: Eighty-four patients with lung cancer undergoing VATS lobectomies were recruited. INTERVENTIONS: Patients were randomly assigned to one of the following two groups: oxycodone and dexmedetomidine (group OD) or oxycodone alone (group O). Before induction of anesthesia, patients in group OD received 0.5 µg/kg, dexmedetomidine diluted to 20 mL with physiologic saline and infused for 10 minutes intravenously. The PCA protocol was 50 mg of oxycodone and 0.05 µg/kg/h dexmedetomidine diluted to 100 mL. Patients in group O received 20 mL of physiologic saline infused for 10 minutes. Their PCA protocol consisted of 50 mg of oxycodone diluted to 100 mL. Intravenous PCA was used for postoperative analgesia (lasting for 48 h). MEASUREMENTS AND MAIN RESULTS: Pain at rest and during movement was assessed by a blinded observer using the Visual Analog Scale pain score (VAS) at 4, 6, 24, and 48 hours after surgery, and the level of sedation simultaneously was assessed using the Ramsay Sedation Scale. Total oxycodone consumption, requirements for rescue analgesia, side effects, and satisfaction with pain management were recorded within 48 hours after surgery. Eighty patients' data were analyzed at the end of the study (40 in each group). Visual Analog Scale scores decreased at 4, 6, and 24 hours at rest and during movement in group OD compared with group O (p<0.05). The level of patient satisfaction in group OD was significantly higher than that in group O (p<0.05). Oxycodone consumption in group OD was significantly lower than that in group O (p<0.001). Group O experienced more nausea and vomiting 6 hours after surgery than did group OD (p< 0.05). CONCLUSION: The combination of oxycodone and dexmedetomidine for PCA after VATS lobectomy can reduce oxycodone consumption, improve patient satisfaction, and provide better analgesia with fewer side effects (nausea and vomiting) compared with PCA with oxycodone alone.

Activation of NLRP3 inflammasome in alveolar macrophages contributes to mechanical stretch-induced lung inflammation and injury.

Mechanical ventilation of lungs is capable of activating the innate immune system and inducing sterile inflammatory response. The proinflammatory cytokine IL-1ß is among the definitive markers for accurately identifying ventilator-induced lung inflammation. However, mechanisms of IL-1ß release during mechanical ventilation are unknown. In this study, we show that cyclic stretch activates the nucleotide-binding oligomerization domain-like receptor containing pyrin domain 3 (NLRP3) inflammasomes and induces the release of IL-1ß in mouse alveolar macrophages via caspase-1- and TLR4-dependent mechanisms. We also observed that NADPH oxidase subunit gp91(phox) was dispensable for stretch-induced cytokine production, whereas mitochondrial generation of reactive oxygen species was required for stretch-induced NLRP3 inflammasome activation and IL-1ß release. Further, mechanical ventilation activated the NLRP3 inflammasomes in mouse alveolar macrophages and increased the production of IL-1ß in vivo. IL-1ß neutralization significantly reduced mechanical ventilation-induced inflammatory lung injury. These findings suggest that the alveolar macrophage NLRP3 inflammasome may sense lung alveolar stretch to induce the release of IL-1ß and hence may contribute to the mechanism of lung inflammatory injury during mechanical ventilation.

Inhibition of acid-sensing ion channel currents by propofol in rat dorsal root ganglion neurons.

Acid-sensing ion channels (ASICs), part of the epithelial sodium channel/degenerin family, are activated by extracellular protons. The ASICs play a significant role in the acidosis-mediated perception of pain. The anaesthetic agent propofol also exerts antinociceptive effects, but the underlying mechanisms for this effect are not clear. We used whole-cell patch clamping to investigate the effect of propofol on proton-gated currents in: (i) rat dorsal root ganglion (DRG) neurons; and (ii) HEK293 cells transfected with either ASIC1a or ASIC3. Propofol inhibited the amplitude of proton-gated currents in DRG neurons, but did not change the sensitivity of ASICs to H(+). Notably, propofol altered acid-evoked excitability of rat DRG neurons and decreased the number of action potentials induced by acid stimuli. In addition, we demonstrated that propofol inhibited ASICs by directly binding with these channels in HEK293 cells. These results suggest that propofol inhibits proton-gated currents in DRG neurons and that inhibition of proton-gated currents explains, in part, the antinociceptive effects of propofol in primary afferent neurons.

Mycophenolate mofetil attenuates myocardial ischemia-reperfusion injury via regulation of the TLR4/NF-κB signaling pathway.

It has been well documented that the Toll-like receptor 4 (TLR4)/NF-κB signaling pathway mediates early inflammatory responses during myocardial ischemia and reperfusion (MI/R). Mycophenolate mofetil (MMF), an immunosuppressive agent, has been shown to confer protective effects against ischemia/reperfusion injury, possibly through its immunosuppressive and anti-inflammatory actions. The aim of the present study was to investigate whether MMF could modulate the TLR4/NF-κB signaling, inhibit cell apoptosis and subsequently attenuate MI/R injury. MMF (20 mg/kg) or vehicle was administered to SD rats by gavage. The rats were then subjected to MI/R injury. The results showed that after MI/R, the expressions of myocardial TLR4 and NF-κB were significantly increased, and apoptosis of cardiomyocytes was induced, as evidenced by the decreased mitochondrial membrane potential (MMP), decreased Bcl-2 protein level, and increased Bax expression. Administration of MMF attenuated MI/R injury. Further studies demonstrated that MMF inhibited the induction of TLR4, NF-κB and Bax expression, and restored the expression of bcl-2. Moreover, increased myeloperoxidase activity and serum level of tumor necrotic factor α induced by MI/R injury were also inhibited by MMF treatment. In conclusion, our results demonstrated that MMF attenuates MI/R injury through inhibition of the TLR4/NF-κB signaling pathway, which led to reduced inflammatory reaction and subsequently myocardial cell apoptosis.

Recombinant human erythropoietin attenuates neuronal apoptosis and cognitive defects via JAK2/STAT3 signaling in experimental endotoxemia.

BACKGROUND: Septic encephalopathy is characterized by changes in mental status and an increase in neuronal apoptosis. Accumulating evidence has shown that recombinant human erythropoietin (rhEPO) protects brain against ischemia and hypoxia injury. However, whether rhEPO exerts neuroprotective effects on septic encephalopathy remains unclear. We designed the current study to evaluate possible neuroprotection of rhEPO in a model of sepsis. METHODS: For this in vitro study, we determined hippocampal neuronal apoptosis by lactate dehydrogenase release, cell counting kit-8 assay, and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling staining after treatment with lipopolysaccharide. We transfected the signal transducer and activator of transcription 3 (STAT3) short hairpin RNA at 14 d in vitro for 48 h. For the in vivo study, we performed cecal ligation and peroration surgery. We detected the expression of phospho-Janus-activated kinase 2 (JAK2), total JAK2, phospho-STAT3, total STAT3, Bax and Bcl-XL by Western blot, and examined behavior using the Morris water maze. RESULTS: Treatment with rhEPO reduces apoptosis and increases cell viability in lipopolysaccharide-treated neuronal cultures. In cecal ligation and peroration rats, rhEPO attenuated the inhibition of phospho-JAK2 and phospho-STAT3. In addition, rhEPO enhanced the expression of Bcl-XL, but depressed Bax, which was abolished by additional administration of inhibitor of JAK2/STAT3 signaling 2-cyano-3-(3,4-dihydroxyphenyl)-N-(benzyl)-2-propenamide,2-cyano-3-(3,4-dihydroxyphenyl)-N-(phenylmethyl)-2-propenamide or (E)-3(6-bromopyridin-2-yl)-2-cyano-N-([S0-1-phenylethyl]acrylamide)in vivo, and was ameliorated by STAT3 short hairpin RNA transfection in vitro. Alternatively, we confirmed the neuronal protective effect of rhEPO by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labelingstaining. For the Morris water maze study, rhEPO improved learning and memory disorders without an alternation in locomotor activity. CONCLUSIONS: These results indicated that rhEPO improves brain dysfunction by reducing neuronal apoptosis, and JAK2/STAT3 signaling is likely to be involved. Application of rhEPO may serve as a potential therapy for the treatment of septic encephalopathy.

Propofol reduces lipopolysaccharide-induced, NADPH oxidase (NOX 2) mediated TNF- α and IL-6 production in macrophages.

During an infection, lipopolysaccharide (LPS) stimulates the production of reactive oxygen species (ROS), which is mediated, in large part, by nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (NOXs); NOX2 is the major NOX isoform found in the macrophage cell membrane. While the immunomodulatory activity of propofol is highly documented, its effect on the LPS-induced NOX2/ROS/NF-κB signaling pathway in macrophages has not been addressed. In present study, we used murine macrophage cell line RAW264.7 pretreated with propofol and stimulated with LPS. IL-6 and TNF-α expression, ROS production, and NOX activity were determined. Results showed that propofol attenuated LPS-induced TNF-α and IL-6 expression. Moreover, LPS-stimulated phosphorylation of NF-κB and generation of ROS were weakened in response to propofol. Propofol also reduced LPS-induced NOX activity and expression of gp91phox and p47phox. We conclude that propofol modulates LPS signaling in macrophages by reducing NOX-mediated production of TNF-α and IL-6.

The role of tyrosine kinase in Ca²âº-independent contraction of the ropivacaine on rat aortic smooth muscle.

The tyrosine kinase signaling pathway plays an important role in the mediation of Ca²âº independent mechanisms of smooth muscle contraction. Several components of this pathway, including protein kinase C (PKC), p44/42 mitogen-activated protein kinase (p44/42 MAPK) and Rho-kinase are involved in Ca²âº independent mechanisms. Whether the tyrosine kinase pathway mediates vasoconstriction induced by the anesthetic ropivacaine remains unclear. The present study was designed to examine the role of tyrosine kinase in ropivacaine-induced, Ca²âº-independent contraction of rat aortic smooth muscle. The effects of tyrosine kinase inhibitor on ropivacaine-induced contractile response were observed by isometric force measurement. The protein tyrosine phosphorylation, PKC, p44/42 MAPK, and membrane translocation of Rho-kinase were examined by Western blotting. Ropivacaine induced a concentration-dependent contractile response, and showed a number of effects on protein tyrosine phosphorylation. In this study, phosphorylation levels were shown to increase at lower concentrations of ropivacaine, but the levels decline at higher concentrations in rat aortic rings attenuated by the tyrosine kinase inhibitor genistein in a concentration-dependent fashion. Ropivacaine-induced phosphorylation of PKC and p44/42 MAPK and Rho-kinase membrane translocation were also significantly attenuated by genistein in similar decreasing manner as the PKC inhibitor bisindolylmaleimide I (Bis I) and the Rho-kinase inhibitor, Y27632, but to a lesser degree than that by the p44/42 MAPK inhibitor, PD 098059. Our results showed that the ropivacaine-induced, Ca²âº independent-mediated contraction of rat aortic smooth muscle is, in part, regulated by tyrosine kinase-catalyzed protein tyrosine phosphorylation.

Sevoflurane preconditioning improves neuroinflammation in cerebral ischemia/reperfusion induced rats through ROS-NLRP3 pathway.

AIM: We aimed to study the influence of sevoflurane on the nucleotide-binding domain and Leucine-rich repeat protein 3 (NLRP3) pathways in rats with cerebral ischemia/reperfusion (I/R) injury. METHODS: Sixty Sprague-Dawley rats were equally divided into five groups randomly: sham-operated, cerebral I/R, sevoflurane (Sevo), NLRP3 inhibitor-treated (MCC950), and sevoflurane and NLRP3 inducer-treated groups. Rats' neurological functions were assessed using Longa scoring after 24 h of reperfusion, after which they were sacrificed, and cerebral infarction area was determined by triphenyl tetrazolium chloride staining. Pathological changes in damaged portions were assessed using hematoxylin-eosin and Nissl staining, and cell apoptosis was detected by terminal-deoxynucleotidyl transferase-mediated nick end labeling staining. Interleukin 1 beta (IL-1ß), tumor necrosis factor α (TNF-α), interleukin-6 (IL-6), interleukin-18 (IL-18), malondialdehyde (MDA), and superoxide dismutase (SOD) levels in brain tissues were determined using enzyme-linked immunosorbent assay. Reactive oxygen species (ROS) levels were analyzed using a ROS assay kit. Protein levels of NLRP3, caspase-1, and IL-1ß were determined by western blot. RESULTS: Neurological function scores, cerebral infarction areas, and neuronal apoptosis index were decreased in the Sevo and MCC950 groups than in the I/R group. IL-1ß, TNF-α, IL-6, IL-18, NLRP3, caspase-1, and IL-1ß levels decreased in the Sevo and MCC950 groups (p < 0.05). ROS and MDA levels increased, but SOD levels increased in the Sevo and MCC950 groups than in the I/R group. NLPR3-inducer nigericin eliminated the protective effects of sevoflurane on cerebral I/R injury in rats. CONCLUSION: Sevoflurane could alleviate cerebral I/R-induced brain damage by inhibiting the ROS-NLRP3 pathway.