Propofol attenuated liver transplantation-induced acute lung injury via connexin43 gap junction inhibition

General anesthetic agents induce neurotoxicity through astrocytes

ABSTRACT

Neuroscientists have recognized the importance of astrocytes in regulating neurological function and their influence on the release of glial transmitters. Few studies, however, have focused on the effects of general anesthetic agents on neuroglia or astrocytes. Astrocytes can also be an important target of general anesthetic agents as they exert not only sedative, analgesic, and amnesic effects but also mediate general anesthetic-induced neurotoxicity and postoperative cognitive dysfunction. Here, we analyzed recent advances in understanding the mechanism of general anesthetic agents on astrocytes, and found that exposure to general anesthetic agents will destroy the morphology and proliferation of astrocytes, in addition to acting on the receptors on their surface, which not only affect Ca2+ signaling, inhibit the release of brain-derived neurotrophic factor and lactate from astrocytes, but are even involved in the regulation of the pro- and anti-inflammatory processes of astrocytes. These would obviously affect the communication between astrocytes as well as between astrocytes and neighboring neurons, other neuroglia, and vascular cells. In this review, we summarize how general anesthetic agents act on neurons via astrocytes, and explore potential mechanisms of action of general anesthetic agents on the nervous system. We hope that this review will provide a new direction for mitigating the neurotoxicity of general anesthetic agents.

Downregulation of connexin 43-based gap junctions underlies propofol-induced excessive relaxation in hypertensive vascular smooth muscle cells

BACKGROUND

Postinduction hypotension caused by propofol remains a non-negligible problem for anesthesiologists, and is especially severe in chronic hypertensive patients with long-term vasoconstriction and decreased vascular elasticity. The functional change in gap junctions composed of Cx43 (Cx43-GJs) is reported as the biological basis of synchronized contraction or relaxation of blood vessels. Thus, we investigated the role of Cx43-GJs in propofol-induced dramatic blood pressure fluctuations in chronic hypertensive patients, and their internal mechanisms.

METHODS

Human umbilical artery smooth muscle cells (HUASMCs) were pretreated with long-term angiotensin II (Ang II), with or without propofol, to simulate the contraction and relaxation of normal and hypertensive VSMCs during anesthesia induction. The levels of F-actin polymerization and MLC2 phosphorylation were used as indicators to observe the contraction and relaxation of HUASMCs. Different specific activators, inhibitors and siRNAs were used to explore the role of Cx43-GJs and Ca²⁺ as well as the RhoA/ LIMK2/cofilin and RhoA/MLCK signaling pathways in the contraction and relaxation of normal and hypertensive HUASMCs.

RESULTS

Both F-actin polymerization and MLC2 phosphorylation were significantly enhanced in Ang II-pretreated HUASMCs, along with higher expression of Cx43 protein and stronger function of Cx43-GJs than in normal HUASMCs. However, with propofol administration, similar to Gap26 and Cx43-siRNA, the function of Cx43-GJs in Ang II-pretreated HUASMCs was inhibited compared with that in normal HUASMCs, accompanied by a larger decrease in intracellular Ca²⁺ and the RhoA/LIMK2/cofilin and RhoA/MLCK signaling pathways. Eventually F-actin polymerization and MLC2 phosphorylation were more dramatically decreased. However, these effects could be reversed by RA with enhanced Cx43-GJ function.

CONCLUSION

Long-term exposure to Ang II significantly enhanced the expression of the Cx43 protein and function of Cx43-GJs in HUASMCs, resulting in the accumulation of intracellular Ca²⁺ and the activation of its downstream RhoA/LIMK2/cofilin and RhoA/MLCK signaling pathways, which maintained HUASMCs in a state of excessive-contraction. With inhibition of Cx43-GJs by propofol in Ang II-pretreated HUASMCs, intracellular Ca²⁺ and its downstream signaling pathways were dramatically inhibited, which ultimately excessively relaxed HUASMCs. This is the reason why the blood pressure fluctuation of patients with chronic hypertension was more severe after receiving propofol induction. Video Abstract.

Construction and validation of a pulmonary complication score for patients after liver transplantation

PURPOSE

Identification of preoperative risk factors associated with pulmonary complications may benefit high-risk patients from more intense surveillance and earlier interventions in liver transplantation (LT). Our study aimed to identify risk factors for predicting pulmonary complications in LT patients.

MATERIALS AND METHODS

The discovery data set enrolled 208 patients who underwent orthotopic LT while the validation data set included 117 patients. Clinical data were collected from medical history retrospectively and risk factors were determined by logistic regression analyses. The pulmonary complication score (PCS-LT) was established and validated for predicting pulmonary complications after LT.

RESULTS

In the discovery data set, 47 (22.6%) participants experienced pulmonary complications following LT. Four independent risk factors for pulmonary complications were identified by multivariate logistic regression analysis, including preoperative abnormal pulmonary function (OR = 4.743, p < .001), elevated lymphocyte count (OR = 2.336, p = .027), hypoproteinemia (OR = 2.635, p = .030), and hypokalemia (OR = 5.257, p = .003), and PCS-LT based on these factors was established. ROC analyses showed PCS-LT could predict PC in both the discovery data set (area under curve [AUC] .752, 95% confidence interval [CI] .687-.809) and the validation data set (AUC .754, 95% CI, .666-.829). The PCS-LT demonstrated superior predictive value (AUC .735, 95% CI, .703-.799) to APACHE II score (AUC .653, 95% CI, .599-.705) in the combined data set (p = .032). Meanwhile, PCS-LT > 1 was used as the cut-off value and has prognostic significance in LT patients.

CONCLUSIONS

The PCS-LT score, consisting of abnormal pulmonary function, elevated lymphocyte count, hypoproteinemia, and hypokalemia, could predict pulmonary complications after LT.

The Potential Role of Connexins in the Pathogenesis of Atherosclerosis

Connexins (Cx) are members of a protein family which enable extracellular and intercellular communication through hemichannels and gap junctions (GJ), respectively. Cx take part in transporting important cell-cell messengers such as 3',5'-cyclic adenosine monophosphate (cAMP), adenosine triphosphate (ATP), and inositol 1,4,5-trisphosphate (IP3), among others. Therefore, they play a significant role in regulating cell homeostasis, proliferation, and differentiation. Alterations in Cx distribution, degradation, and post-translational modifications have been correlated with cancers, as well as cardiovascular and neurological diseases. Depending on the isoform, Cx have been shown either to promote or suppress the development of atherosclerosis, a progressive inflammatory disease affecting large and medium-sized arteries. Cx might contribute to the progression of the disease by enhancing endothelial dysfunction, monocyte recruitment, vascular smooth muscle cell (VSMC) activation, or by inhibiting VSMC autophagy. Inhibition or modulation of the expression of specific isoforms could suppress atherosclerotic plaque formation and diminish pro-inflammatory conditions. A better understanding of the complexity of atherosclerosis pathophysiology linked with Cx could result in developing novel therapeutic strategies. This review aims to present the role of Cx in the pathogenesis of atherosclerosis and discusses whether they can become novel therapeutic targets.

A new side-effect of sufentanil: increased monocyte-endothelial adhesion

BACKGROUND

Opioids have been identified by the World Health Organization to be 'indispensable for the relief of pain and suffering'. Side-effects, such as nausea, vomiting, postoperative delirium, and effects on breathing, of opioids have been well investigated; however, the influence of opioids on monocyte-endothelial adherence has never been reported. Therefore, we explored the effects of representative opioids, fentanyl, sufentanil, and remifentanil, on monocyte-endothelial adherence and the underlying mechanisms.

METHODS

We built a cell adhesion model with U937 monocytes and human umbilical vein endothelial cells (HUVECs). Two kinds of connexin43 (Cx43) channel inhibitors, 18-α-GA and Gap 27, were used to alter Cx43 channel function in U937 monocytes and HUVECs, respectively, to determine the effects of Cx43 channels on U937-HUVEC adhesion. Subsequently, the effects of fentanyl, sufentanil and remifentanil on Cx43 channel function and U937-HUVEC adhesion were explored.

RESULTS

When fentanyl, sufentanil and remifentanil acted on monocytes or endothelial cells, their effects on monocyte-endothelial adherence differed. When acting on U937 monocytes, sufentanil significantly increased U937-HUVEC adhesion which was associated with reduced release of ATP from Cx43 channels, while fentanyl and remifentanil did not have these influences. Although sufentanil could also inhibit Cx43 channel function in HUVECs, it had no effect on ATP release from HUVECs or U937-HUVECs adhesion.

CONCLUSIONS

We demonstrated that sufentanil application increases monocyte-endothelial adherence which was associated with reduced release of ATP from Cx43 channels in monocytes. This side-effect of sufentanil should be considered seriously by clinicians.

Propofol Regulates the TLR4/NF-κB Pathway Through miRNA-155 to Protect Colorectal Cancer Intestinal Barrier

Surgery for colorectal cancer (CRC) can cause damage to the intestinal mucosal barrier and lead to bacterial invasion. This study mainly analyzed whether propofol (PPF) could protect the intestinal mucosal barrier damage caused by CRC surgery, and explored its molecular mechanism. A mouse CRC model was constructed using azomethane and dextran sulfate sodium. During anesthesia, continuous intravenous injection of PPF was used for intervention. The influences of PPF on intestinal mucosal permeability and bacterial invasion were detected. The levels of microRNA (miR)-155, Toll-like receptor 4 (TLR4)/NF-κB in the intestinal mucosa, and the location of miR-155 were detected by fluorescence in situ hybridization (FISH). Mouse macrophages were used to analyze the regulation of miR-155 on the secretion of inflammatory cytokines through the TLR4/NF-κB pathway. PPF treatment promoted the expression of tight junction protein in the intestinal mucosa, protected the intestinal barrier, inhibited the translocation of intestinal bacteria, and increased the level of the beneficial bacterium Lactobacillus on the mucosal surface. In addition, PPF treatment could inhibit the expression of miR-155, TLR4/NF-KB, and reverse inflammatory response. miR-155 was expressed in macrophages of intestinal mucosa tissue. Overexpression of miR-155 promoted the nuclear translocation of NF-κB and the expression of inflammatory cytokines in macrophages. The use of VIPER to inhibit TLR4 reversed the pro-inflammatory effects of miR-155. PPF might inhibit the activation of the NF-κB pathway by downregulating miR-155 expression, thereby reducing the secretion of inflammatory cytokines. This might be the mechanism by which PPF protected the intestinal barrier of CRC surgical model mice.

Oxidative stress under general intravenous and inhalation anaesthesia

Oxidative stress occurs when reactive oxygen species (ROS) production overwhelms cell protection by antioxidants. This review is focused on general anaesthesia-induced oxidative stress because it increases the rate of complications and delays recovery after surgery. It is important to know what effects of anaesthetics to expect in terms of oxidative stress, particularly in surgical procedures with high ROS production, because their either additive or antagonistic effect may be pivotal for the outcome of surgery. In vitro and animal studies on this topic are numerous but show large variability. There are not many human studies and what we know has been learned from different surgical procedures measuring different endpoints in blood samples taken mostly before and after surgery. In these studies most intravenous anaesthetics have antioxidative properties, while volatile anaesthetics temporarily increase oxidative stress in longer surgical procedures.

Ulinastatin attenuates monocyte-endothelial adhesion via inhibiting ROS transfer between the neighboring vascular endothelial cells mediated by Cx43

Ulinastatin is widely used in the treatment of pancreatitis and sepsis, because of its excellent anti-inflammatory and antioxidant effects. However, its effects on atherosclerosis, an inflammatory vascular disease, are rarely reported. Therefore, in present study, we explored effects of ulinastatin on monocyte-endothelial adhesion, the initiator of atherosclerosis. We used U937 monocytes and angiotensin II-stimulated human umbilical vein endothelial cells (HUVECs) to build the model of monocyte-endothelial adhesion. Different methods were used to change the function of connexin43 (Cx43), the level of ROS, the activation of JAK2/STAT3 signaling pathway and its downstream MMP2 and MMP9 expression, and then the influences of ulinastatin on U937-HUVECs adhesion and the adhesion molecules were observed. The results showed that ulinastatin could attenuate ROS transmission between the neighboring HUVECs via inhibiting Cx43 function. With the decrease of ROS, JAK2/STAT3 signaling pathway and its downstream MMP2 and MMP9 expression were downregulated. Ultimately, important adhesion molecules expression, such as VCAM-1, ICAM-1, sVCAM-1 and sICAM-1, and U937-HUVECs adhesion, were both reduced. Thus, we can conclude that ulinastatin attenuates adhesion molecules expression and monocyte-endothelial adhesion, mechanism of which is related that ulinastatin inhibits ROS transfer between the neighboring vascular endothelial cells mediated by Cx43, resulting in the inactivation of JAK2/STAT3 signaling pathway, and its downstream MMP2 and MMP9 expression decrease.

Dexmedetomidine Attenuates LPS-Induced Monocyte-Endothelial Adherence via Inhibiting Cx43/PKC-α/NOX2/ROS Signaling Pathway in Monocytes

Dexmedetomidine is widely used for sedating patients in operation rooms or intensive care units. Its protective functions against oxidative stress, inflammation reaction, and apoptosis have been widely reported. In present study, we explored the effects of dexmedetomidine on monocyte-endothelial adherence. We built lipopolysaccharide- (LPS-) induced monocyte-endothelial adherence models with U937 monocytes and human umbilical vein endothelial cells (HUVECs) and observed the effects of dexmedetomidine on U937-HUVEC adhesion. Specific siRNA was designed to knock-down Connexin43 (Cx43) expression in U937 monocytes. Gö6976, GSK2795039, and NAC were used to inhibit PKC-α, NOX2, and ROS, respectively. Then, we detected whether dexmedetomidine could downregulate Cx43 expression and its downstream PKC-α/NOX2/ROS signaling pathway activation and ultimately result in the decrease of U937-HUVEC adhesion. The results showed that dexmedetomidine, at its clinically relevant concentrations (0.1 nM and 1 nM), could inhibit adhesion of molecule expression (VLA-4 and LFA-1) and U937-HUVEC adhesion. Simultaneously, it also attenuated Cx43 expression in U937 monocytes. With the downregulation of Cx43 expression, the activity of PKC-α and its related NOX2/ROS signaling pathway were reduced. Inhibiting PKC-α/NOX2/ROS signaling pathway with Gö6976, GSK2795039, and NAC, respectively, VLA-4, LFA-1 expression, and U937-HUVEC adhesion were all decreased. In summary, we concluded that dexmedetomidine, at its clinically relevant concentrations (0.1 nM and 1 nM), decreased Cx43 expression in U937 monocytes and PKC-α associated with carboxyl-terminal domain of Cx43 protein. With the downregulation of PKC-α, the NOX2/ROS signaling pathway was inhibited, resulting in the decrease of VLA-4 and LFA-1 expression. Ultimately, U937-HUVEC adhesion was reduced.

Dexmedetomidine Attenuates Monocyte-Endothelial Adherence via Inhibiting Connexin43 on Vascular Endothelial Cells

Current studies have identified the multifaceted protective functions of dexmedetomidine on multiple organs. For the first time, we clarify effects of dexmedetomidine on monocyte-endothelial adherence and whether its underlying mechanism is relative to connexin43 (Cx43), a key factor regulating monocyte-endothelial adherence. U937 monocytes and human umbilical vein endothelial cells (HUVECs) were used to explore monocyte-endothelial adherence. Two special siRNAs were designed to knock down Cx43 expression on HUVECs. U937-HUVEC adhesion, adhesion-related molecules, and the activation of the MAPK (p-ERK1/2, p-p38, and p-JNK1/2) signaling pathway were detected. Dexmedetomidine, at its clinically relevant concentrations (0.1 nM and 1 nM), was given as pretreatments to HUVECs. Its effects on Cx43 and U937-HUVEC adhesion were also investigated. The results show that inhibiting Cx43 on HUVECs could attenuate the contents of MCP-1, soluble ICAM-1 (sICAM-1), soluble VCAM-1 (sVCAM-1), and the nonprocessed variants of the adhesion molecules ICAM-1 and VCAM-1 and ultimately result in U937-HUVEC adhesion decrease. Meanwhile, the activation of MAPKs was also inhibited. U0126 (inhibiting p-ERK1/2) and SB202190 (inhibiting p38) decreased the contents of MCP-1, sICAM-1, and sVCAM-1, but SP600125 (inhibiting p-JNK1/2) had none of these effects. ICAM-1 and VCAM-1 could be regulated in a similar way. Dexmedetomidine pretreatment inhibited Cx43 on HUVECs, the activation of MAPKs, and U937-HUVEC adhesion. Therefore, we conclude that dexmedetomidine attenuates U937-HUVEC adhesion via inhibiting Cx43 on HUVECs modulating the activation of MAPK signaling pathways.

Improved multiparametric scrape loading-dye transfer assay for a simultaneous high-throughput analysis of gap junctional intercellular communication, cell density and viability

Gap junctional intercellular communication (GJIC) is a vital cellular process required for maintenance of tissue homeostasis. In vitro assessment of GJIC represents valuable phenotypic endpoint that could be effectively utilized as an integral component in modern toxicity testing, drug screening or biomedical in vitro research. However, currently available methods for quantifying GJIC with higher-throughputs typically require specialized equipment, proprietary software and/or genetically engineered cell models. To overcome these limitations, we present here an innovative adaptation of traditional, fluorescence microscopy-based scrape loading-dye transfer (SL-DT) assay, which has been optimized to simultaneously evaluate GJIC, cell density and viability. This multiparametric method was demonstrated to be suitable for various multiwell microplate formats, which facilitates an automatized image acquisition. The assay workflow is further assisted by an open source-based software tools for batch image processing, analysis and evaluation of GJIC, cell density and viability. Our results suggest that this approach provides a simple, fast, versatile and cost effective way for in vitro high-throughput assessment of GJIC and other related phenotypic cellular events, which could be included into in vitro screening and assessment of pharmacologically and toxicologically relevant compounds.

Propofol attenuates monocyte-endothelial adhesion via modulating connexin43 expression in monocytes

AIMS

Monocyte-endothelial adhesion is considered to be the primary initiator of inflammatory vascular diseases, such as atherosclerosis. Connexin 43 (Cx43) has been reported to play an important part in this process, however, the underlying mechanisms are not fully understood. Intravenous anesthetics, propofol is commonly used in the perioperative period and in the intensive care unit, and considered to have good anti-inflammatory and antioxidant effects. Thus, we speculate that propofol could influence monocyte-endothelial adhesion, and explore whether its possible mechanism is relative with Cx43 expression in U937 monocytes influencing cell adhesion of U937 monocytes to human umbilical vein endothelial cells (HUVEC).

MAIN METHODS

Cx43-siRNAs or pc-DNA-Cx43 were used to alter Cx43 expression in U937 monocytes. Propofol was given as pretreatments to U937 monocytes. Then, cell adhesion, ZO-1, LFA-1, VLA-4, COX and MCP-1 were determined. PI3K/AKT/NF-κB signaling pathway was explored to clarify the possible mechanism.

KEY FINDINGS

Alternation of Cx43 expression affects cell adhesion and adhesion molecules significantly, such as ZO-1, LFA-1, VLA-4, COX-2 and MCP-1, the mechanism of which is relative with Cx43 influencing the activation of PI3K/AKT/NF-κB signaling pathway. Preconditioning with propofol at its clinically relevant anesthesia concentration attenuates cell adhesion. Propofol not only decreases Cx43 expression in U937 monocytes, but also depresses the activation of PI3K/AKT/NF-κB signaling pathway.

SIGNIFICANCE

Modulation Cx43 expression in U937 monocytes could affect cell adhesion via regulating the activation of PI3K/AKT/NF-κB signaling pathway. Propofol attenuates cell adhesion via inhibiting Cx43 and its downstream signaling pathway of PI3K/AKT/NF-κB.

Down-regulation of Cx43 expression on PIH-HUVEC cells attenuates monocyte-endothelial adhesion

INTRODUCTION

Pregnancy-induced hypertension (PIH) is the most common serious complication of pregnancy, resulting in significant maternal and fetal morbidity and mortality. Vasospasm is the main pathogenesis of PIH, which leads to the hemodynamic changes and the injury of vascular endothelial cells. However, the underlying mechanism is still unclear. Monocyte-endothelial adhesion is always considered to be one of the most important indicators of vascular endothelial cell injury. Connexin43 (Cx43) plays an important part in monocyte-endothelial adhesion. Thus, we explored effects of Cx43 on cell adhesion in PIH-induced vascular endothelial cells injury.

METHODS

We obtained human umbilical vein endothelial cells (HUVECs) from patients with or without PIH. Different methods, such as inhibitors: oleamide and Gap26, or specific siRNA were used to alter Cx43 channels function or protein expression in normal or PIH-HUVECs. U937-HUVECs adhesion, adhesion molecules expression, such as VCAM-1 and ICAM-1, and the activity of PI3K/AKT/NF-κB signaling pathway were determined.

RESULTS

Monocyte-endothelial adhesion on PIH-HUVECs was much more obvious than that on normal HUVECs. Inhibition of Cx43 protein expression could attenuate cell adhesion significantly, however, function of Cx43 channels had no effects on it. Alternation of Cx43 protein expression on PIH-HUVECs mediated VCAM-1 and ICAM-1 expression via regulating the activity of PI3K/AKT/NF-κB signaling pathway.

CONCLUSIONS

We firstly reported Cx43 protein expression on PIH-HUVECs was much higher than that on normal HUVECs. Elevation of Cx43 protein expression within the vasculature resulted in PI3K/AKT/NF-κB signaling pathway activation and VCAM-1 and ICAM-1 over-expression, which ultimately lead to monocyte-endothelial adhesion increase.

Effects of propofol on wound closure and barrier function of cultured endothelial cells: An in vitro experimental study

BACKGROUND

Propofol is widely used in routine clinical practice for the induction and maintenance of anaesthesia. Although propofol is regarded as a well tolerated anaesthetic, its effect on intact or damaged endothelial cells has not yet been elucidated.

OBJECTIVE

The aim of this study was to investigate the effects of different concentrations of propofol on cell damage, metabolic activity, barrier function and wound healing capacity of human endothelial cells.

DESIGN

An in vitro investigation.

SETTING

Research Laboratory of the Department of Anaesthesiology and Intensive Care Medicine, University Hospital Schleswig-Holstein, Kiel, Germany.

MATERIALS

In vitro cultures of primary human umbilical vein endothelial cells (HUVECs).

INTERVENTIONS

Intact HUVEC or wounded HUVEC monolayers were incubated with or without different concentrations of propofol (10, 30 and 100 μmol l).

MAIN OUTCOME MEASURES

Cell damage, metabolic activity, monolayer permeability, wound healing capacity, protein phosphorylation.

RESULTS

Propofol did not alter the morphology, induce cell damage or influence metabolic activity of intact HUVEC cells. Permeability of a HUVEC monolayer was increased by propofol 100 μmol l (P < 0.05). Wound closure was inhibited by the addition of propofol 30 and 100 μmol l (P < 0.05 and P < 0.01). This effect was associated with increased phosphorylation of extracellular signal regulated kinases (Erk) 1/2 (30 and 100 μmol l; both P < 0.05) and decreased phosphorylation of Rho kinase (Rock) (100 μmol l; P < 0.05).

CONCLUSION

Propofol does not damage intact endothelial cells, but increases permeability of an endothelial cell monolayer at high concentrations and inhibits wound closure in vitro. Further experimental and clinical in vivo research should be performed to clarify the influence of propofol on endothelial wound healing.

Protective effects of propofol on experimental neonatal acute lung injury

The present study aimed to investigate the effects of propofol on neonatal acute lung injury (ALI) in a rat model and to examine the molecular mechanisms underlying propofol function. A rat model of ALI was established by intraperitoneal injection of lipopolysaccharides (LPS). The neonatal rats were treated with various concentrations of propofol and a lung injury score was assessed. The protein expression levels of pro‑inflammatory cytokines was detected using ELISA. In the present study, oxidative stress was determined by measuring the level of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD) in lung tissues. Reverse transcription quantitative‑polymerase chain reaction and western blot analysis were used to examine the mRNA and protein expression levels of the factors downstream to LPS signaling pathway. Treatment with propofol significantly alleviated LPS‑induced lung injury in neonatal rats as suggested by the decreased lung injury score, increased partial pressure of oxygen and decreased lung wet‑dry weight ratio. LPS promoted the upregulation of tumor necrosis factor α (TNF‑α), interleukin (IL)‑6 and IL‑1β in lung tissues and bronchoalveolar lavage fluid from neonatal rats exhibiting ALI. Notably, treatment with propofol decreased the expression levels of these factors. Additionally, LPS caused an increase in the levels of MDA, and a decrease in SOD activity, and treatment with propofol suppressed these effects in a dose‑dependent manner. Furthermore, LPS induced the upregulation of phosphorylated (p‑)p38, nuclear factor κ‑light‑chain‑enhancer of activated B cells (NF‑κB), p‑p65, NLR family pyrin domain containing 3 (NLRP3), apoptosis‑associated speck‑like protein containing CARD and caspase‑1 in lung tissues of neonatal rats, and treatment with propofol was able to downregulate these factors in a dose‑dependent manner. Propofol alleviated lung injury in neonatal rats with LPS‑induced ALI by preventing inflammation and oxidative stress via the regulation of the activity of the p38 mitogen‑activated protein kinase/NF‑κB signaling pathway and the expression levels of the NLRP3 inflammasome.

Cx43 Inhibition Attenuates Sepsis-Induced Intestinal Injury via Downregulating ROS Transfer and the Activation of the JNK1/Sirt1/FoxO3a Signaling Pathway

Intestinal injury has long been considered to play a crucial role in the pathophysiology of sepsis and has even been characterized as the “motor” of it. Thus, we explored the effects of connexin43 (Cx43) on sepsis-induced intestinal injury in order to provide potential therapeutic strategies. Rat cecal ligation and puncture (CLP) models in vivo and cell models (IEC-6 cells) pretreated with LPS in vitro were used in the current study. Firstly, different methods, such as Cx43 inhibitors (18-α-GA and oleamide) or siRNA targeting Cx43 and N-acetyl cysteine (NAC) (a kind of ROS scavenger), were used to observe the effects of Cx43 channels mediating ROS transfer on intestinal injury. Secondly, the influence of ROS content on the activity of the JNK1/Sirt1/FoxO3a signaling pathway was explored through the application of NAC, sp600125 (a JNK1 inhibitor), and nicotinamide (a Sirt1 inhibitor). Finally, luciferase assays and ChIP were used to determine the direct regulation of FoxO3a on proapoptotic proteins, Bim and Puma. The results showed that sepsis-induced intestinal injury presented a dynamic change, coincident with the alternation of Cx43 expression. The inhibition of Cx43 attenuated CLP-induced intestinal injury in vivo and LPS-induced IEC-6 injury in vitro. The changes of Cx43 channel function regulated ROS transfer between the neighboring cells, which mediated the activation of the JNK1/Sirt1/FoxO3a signaling pathway. FoxO3a directly affected its downstream target genes, Bim and Puma, which are responsible for cell or tissue apoptosis. In summary, our results suggest that Cx43 inhibition suppresses ROS transfer and inactivates the JNK1/Sirt1/FoxO3a signaling pathway to protect against sepsis-induced intestinal injury.

Dexmedetomidine and propofol sedation requirements in an autistic rat model

Background

Autism is a challenging neurodevelopmental disorder. Previous clinical observations have suggested altered sedation requirements for children with autism. Our study aimed to test this observation experimentally in an animal model and to explore its possible mechanisms.

Methods

Eight adult pregnant female Sprague-Dawley rats were randomly divided into two groups. Four were injected with intraperitoneal sodium valproate on gestational day 12 and four were injected with normal saline. On postnatal day 28, the newborn male rats were subjected to the open-field test to confirm autistic features. Each rat was injected intraperitoneally with a single dose of propofol (50 mg/kg) or dexmedetomidine (0.2 mg/kg). The times to loss of righting reflex (LORR) and to return of righting reflex (RORR) were recorded. On the following day, all rats were re-sedated and underwent electroencephalography (EEG). Thereafter, the rats were euthanized and their hippocampal gamma-aminobutyric acid type A (GABA_A) and glutamate N-methyl-D-aspartate (NMDA) receptor gene expressions were assessed.

Results

Autistic rats showed significantly longer LORR times and shorter RORR times than did the controls (median LORR times: 12.0 versus 5.0 min for dexmedetomidine and 22.0 versus 8.0 min for propofol; P < 0.05). EEG showed a low-frequency, high-amplitude wave pattern 2 min after LORR in the control rats. Autistic rats showed a high-frequency, low-amplitude awake pattern. Hippocampal GABA_A receptor gene expression was significantly lower and NMDA gene expression was greater in autistic rats.

Conclusions

This study supports the clinical observations of increased anesthetic sedative requirements in children with autism and our biochemical analyses using GABA_A and glutamate receptor gene expression highlight possible underlying mechanisms.

RhoA regulates lipopolysaccharide‑induced lung cell injury via the Wnt/β‑catenin pathway

Ras homolog family member A (RhoA) has been reported to be involved in numerous biological processes; however, the effects of RhoA on acute lung injury (ALI) have yet to be reported. The present study aimed to explore how RhoA affects cell viability, reactive oxygen species (ROS) activity and cell apoptosis in a cell model of lipopolysaccharide (LPS)‑induced ALI. An MTT assay, flow cytometry, reverse transcription‑quantitative polymerase chain reaction and western blotting were used to determine the effects of RhoA on cell viability, apoptosis and ROS activity. The results demonstrated that RhoA inactivation was able to promote cell viability, and decrease apoptosis and ROS activity of LPS‑treated cells. The results of western blotting indicated that RhoA activated the downstream Wnt/β‑catenin signaling pathway and inhibited the expression of apoptotic factors. These findings suggested that RhoA may be involved in ALI progression and could be a novel therapeutic target for this disease.