Dexmedetomidine protects against renal ischemia and reperfusion injury by inhibiting the JAK/STAT signaling activation

Dexmedetomidine on the interplay of IL-6 and STAT3 pathways in adrenal gland damage-induced scalding burns in rats

Scalding burns are a common form of thermal injury that often leads to systemic complications. Pro-inflammatory cytokines like interleukin-6 (IL-6) and the activation of signal transducer and activator of transcription 3 (STAT3) pathways have been linked to the pathophysiology of organ damage caused by burns. This study aimed to investigate the potential therapeutic effects of dexmedetomidine, an α2-adrenergic receptor agonist with anti-inflammatory properties, on the interplay of IL-6 and STAT3 pathways in adrenal gland damage following scalding burns in rats. Twenty-eight rats were divided randomly into four groups. Rats in group 1 (n=7, control) were given only 0.9% intraperitoneal (i.p.) NaCl. Rats in group 2 (n=7, DEX) were exposed to 25°C water for 17 s on day 1 and received 100 mcg/kg/day dexmedetomidine i.p. for 3 days; for rats in group 3 (n=7, Burn), boiling water of 94°C was applied inside for 17 s. Rats in group 4 (n=7, Burn+DEX) were exposed to 94°C water for 17 s and received 100 mcg/kg/day dexmedetomidine i.p. for 3 days. Adrenal gland tissues were histopathological examined, and STAT3, IL-6, and TUNEL staining were performed using immunohistochemically. Our results revealed that scalding burns increased IL-6 and STAT3 expression in the adrenal glands of rats. Histological analysis demonstrated that dexmedetomidine administration ameliorated adrenal gland damage and reduced inflammatory cell infiltration. Our findings suggest that dexmedetomidine protects the adrenal glands in scalding burns. This protection appears to be mediated, at least in part, by its modulation of IL-6 and STAT3 pathways.

Protective effects of pioglitazone in renal ischemia-reperfusion injury (RIRI): focus on oxidative stress and inflammation

BACKGROUND

Renal ischemia-reperfusion injury (RIRI) is a critical phenomenon that compromises renal function and is the most serious health concern related to acute kidney injury (AKI). Pioglitazone (Pio) is a known agonist of peroxisome proliferator-activated receptor-gamma (PPAR-γ). PPAR-γ is a nuclear receptor that regulates genes involved in inflammation, metabolism, and cellular differentiation. Activation of PPAR-γ is associated with antiinflammatory and antioxidant effects, which are relevant to the pathophysiology of RIRI. This study aimed to investigate the protective effects of Pio in RIRI, focusing on oxidative stress and inflammation.

METHODS

We conducted a comprehensive literature search using electronic databases, including PubMed, ScienceDirect, Web of Science, Scopus, and Google Scholar.

RESULTS

The results of this study demonstrated that Pio has antioxidant, anti-inflammatory, and anti-apoptotic activities that counteract the consequences of RIRI. The study also discussed the underlying mechanisms, including the modulation of various pathways such as TNF-α, NF-κB signaling systems, STAT3 pathway, KIM-1 and NGAL pathways, AMPK phosphorylation, and autophagy flux. Additionally, the study presented a summary of various animal studies that support the potential protective effects of Pio in RIRI.

CONCLUSION

Our findings suggest that Pio could protect the kidneys from RIRI by improving antioxidant capacity and decreasing inflammation. Therefore, these findings support the potential of Pio as a therapeutic strategy for preventing RIRI in different clinical conditions.

Dexmedetomidine hydrochloride plus sufentanil citrate inhibits glucose metabolism and epithelial‑mesenchymal transition in human esophageal squamous carcinoma KYSE30 cells by modulating the JAK/STAT3/HIF‑1α axis

Dexmedetomidine hydrochloride (DEX-HCl) and sufentanil citrate (SFC) are commonly used anesthetic drugs for esophageal cancer (EC) surgery. The present study was performed to investigate the effect of DEX-HCl and SFC treatment on glucose metabolism and epithelial-mesenchymal transition in EC. Cell counting kit-8 (CCK8), clonogenic, wound healing and Transwell migration assays were performed to assess the effects of the DEX-HCl and SFC on KYSE30 cell proliferation, invasion and migration. Changes in lactate and glucose levels in KYSE30 cells were also detected. Western blot analysis was used to determine the protein expression levels of the JAK/STAT signaling pathway and glucose metabolism-related proteins. The results of CCK8, clonogenic and wound healing assays demonstrated that DEX-HCl and SFC inhibited KYSE30 cell proliferation, invasion and migration. Similarly, the combined DEX-HCl and SFC treatment significantly reduced lactate production, ATP production and glucose levels in KYSE30 cells. Western blotting indicated that DEX-HCl and SFC could reduce JAK/STAT and metastasis-related protein expression. Demonstrating a reduction in Hexokinase 2, matrix metallopeptidase 2 and 9, N-cadherin and lactate dehydrogenase A protein expression levels. The effects of DEX-HCl and SFC combined treatment were counteracted by the addition of JAK/STAT pathway activator RO8191, which suggested that DEX-HCl and SFC could serve a role in mediating the JAK/STAT signaling pathway in KYSE30 cells.

Ferroptosis in organ ischemia-reperfusion injuries: recent advancements and strategies

Ferroptosis is a newly discovered type of regulated cell death participated in multiple diseases. Different from other classical cell death programs such as necrosis and apoptosis, ferroptosis involving iron-catalyzed lipid peroxidation is characterized by Fe2+ accumulation and mitochondria alterations. The phenomenon of oxidative stress following organ ischemia-reperfusion (I/R) has recently garnered attention for its connection to the onset of ferroptosis and subsequent reperfusion injuries. This article provides a comprehensive overview underlying the mechanisms of ferroptosis, with a further focus on the latest research progress regarding interference with ferroptotic pathways in organ I/R injuries, such as intestine, lung, heart, kidney, liver, and brain. Understanding the links between ferroptosis and I/R injury may inform potential therapeutic strategies and targeted agents.

Renal biopsies from donors with acute kidney injury show different molecular patterns according to the post-transplant function

The utilization of kidneys from donors with acute kidney injury (AKI) is often limited by unpredictable post-transplantation outcomes. The aim of our study was to identify protein mediators implicated in either recovery or failure of these organs. Forty kidney biopsies from donors with (20) and without AKI (20) were selected and then subdivided according to the post-transplant outcome defined as a threshold of 45 ml/min for the eGFR at 1 year from transplantation. Tissue homogenates were analysed by western blot to assess how the levels of 17 pre-selected proteins varied across the four groups. Samples from AKI kidneys with a poor outcome showed a fourfold increase in the levels of PPARg and twofold reduction of STAT1 compared to the other groups (p < 0.05). On the contrary, antioxidant enzymes including TRX1 and PRX3 were increased in the AKI kidneys with a good outcome (p < 0.05). An opposite trend was observed for the detoxifying enzyme GSTp which was significantly increased in the AKI group with poor versus good outcome (p < 0.05). The importance of lipid metabolism (PPARg) and inflammatory signals (STAT1) in the function recovery of these kidneys hints to the therapeutical targeting of the involved pathways in the setting of organ reconditioning.

Macrophage Ontogeny, Phenotype, and Function in Ischemia Reperfusion-Induced Injury and Repair

AKI is characterized by a sudden, and usually reversible, decline in kidney function. In mice, ischemia-reperfusion injury (IRI) is commonly used to model the pathophysiologic features of clinical AKI. Macrophages are a unifying feature of IRI as they regulate both the initial injury response as well as the long-term outcome following resolution of injury. Initially, macrophages in the kidney take on a proinflammatory phenotype characterized by the production of inflammatory cytokines, such as CCL2 (monocyte chemoattractant protein 1), IL-6, IL-1 β , and TNF- α . Release of these proinflammatory cytokines leads to tissue damage. After resolution of the initial injury, macrophages take on a reparative role, aiding in tissue repair and restoration of kidney function. By contrast, failure to resolve the initial injury results in prolonged inflammatory macrophage accumulation and increased kidney damage, fibrosis, and the eventual development of CKD. Despite the extensive amount of literature that has ascribed these functions to M1/M2 macrophages, a recent paradigm shift in the macrophage field now defines macrophages on the basis of their ontological origin, namely monocyte-derived and tissue-resident macrophages. In this review, we focus on macrophage phenotype and function during IRI-induced injury, repair, and transition to CKD using both the classic (M1/M2) and novel (ontological origin) definition of kidney macrophages.

Perioperative acute kidney injury: The renoprotective effect and mechanism of dexmedetomidine

Dexmedetomidine (DEX) is a highly selective and potent α2-adrenoceptor (α2-AR) agonist that is widely used as a clinical anesthetic to induce anxiolytic, sedative, and analgesic effects. In recent years, a growing body of evidence has demonstrated that DEX protects against acute kidney injury (AKI) caused by sepsis, drugs, surgery, and ischemia-reperfusion (I/R) in organs or tissues, indicating its potential role in the prevention and treatment of AKI. In this review, we summarized the evidence of the renoprotective effects of DEX on different models of AKI and explored the mechanism. We found that the renoprotective effects of DEX mainly involved antisympathetic effects, reducing inflammatory reactions and oxidative stress, reducing apoptosis, increasing autophagy, reducing ferroptosis, protecting renal tubular epithelial cells (RTECs), and inhibiting renal fibrosis. Thus, the use of DEX is a promising strategy for the management and treatment of perioperative AKI. The aim of this review is to further clarify the renoprotective mechanism of DEX to provide a theoretical basis for its use in basic research in various AKI models, clinical management, and the treatment of perioperative AKI.

Sirtuin 3 is required for the dexmedetomidine-mediated alleviation of inflammation and oxidative stress in nephritis

INTRODUCTION

Although sirtuin 3 (SIRT3) is known to be involved in dexmedetomidine (DEX)-mediated alleviation of renal ischemia and reperfusion injury, the influence of the association between DEX and SIRT3 on nephritis development remains unclear. In this study, the role of SIRT3 in DEX-mediated amelioration of inflammation and oxidative stress in nephritis as well as the possible underlying mechanism were explored in vivo and in vitro.

METHODS

An animal model of glomerulonephritis was generated by injecting mice with interferon-alpha (IFNα)-expressing adenoviruses, and periodic acid-Schiff staining was then used to reveal pathogenicity-related changes in the renal tissue. Additionally, human embryonic kidney cells (HEK293) and renal mesangial cells (RMCs) were treated with IFNα to establish cell models of inflammation in vitro.

RESULTS

DEX administration alleviated glomerulonephritis in the animal model and upregulated SIRT3 expression in the renal tissue. SIRT3 knockdown inhibited the renoprotective effects of DEX against nephritis. IFNα induced inflammation, oxidative stress, and apoptosis in the RMCs and HEK293 cells and reduced their growth, as evidenced by the evaluation of cytokine levels (enzyme-linked immunosorbent assay), reactive oxygen species generation, catalase and superoxide dismutase activities, nuclear factor-erythroid factor 2-related factor 2/heme oxygenase-1 signal transduction, apoptotic cell proportion, and cell viability. In addition to promoting SIRT3 expression, DEX inhibited IFNα-induced inflammation, oxidative stress, and apoptosis in these cells and promoted their viability. SIRT3 knockdown partially reversed the beneficial effects of DEX on RMCs and HEK293 cells.

CONCLUSIONS

Our results suggest that DEX exhibits renoprotective activity during nephritis progression, protecting renal cells against inflammatory injury by promoting SIRT3 expression.

Dexmedetomidine alleviates propofol-induced neural injury in developing rats

Propofol, a commonly used intravenous anesthetic, has been associated with neurodegeneration in the developing brain upon repeated exposure. Dexmedetomidine is an α2 adrenoceptor agonist that was previously reported to possess neuroprotective properties. Here, we confirmed the impacts of dexmedetomidine on propofol-induced neuroapoptosis and subsequent spatial learning and memory deficits in neonatal rats. We found that dexmedetomidine effectively mitigated propofol-induced spatial learning and memory impairments and improved aversive memory in developing rats. Dexmedetomidine reduced propofol-induced cell apoptosis in the hippocampus and modulated the mRNA expression of Bcl-2 and Bax. Additionally, dexmedetomidine attenuated the propofol-induced increase of inflammatory factors IL-6 and TNF-α. The reduced phosphorylation levels of Akt and CREB levels by propofol were re-activated by dexmedetomidine. In conclusion, our findings demonstrated that dexmedetomidine effectively mitigated propofol-induced cognitive and memory impairments in developing rats by modulating apoptosis and reducing inflammation via activating the Akt/CREB/BDNF signaling pathway. These findings suggest potential strategies to protect the developing brain from the adverse effects of anesthetics and improve patient care in pediatric anesthesia practice.

Dexmedetomidine Pretreatment Protects Against Myocardial Ischemia/Reperfusion Injury by Activating STAT3 Signaling

BACKGROUND

Myocardial infarction is a common perioperative complication, and blood flow restoration causes ischemia/reperfusion injury (IRI). Dexmedetomidine (DEX) pretreatment can protect against cardiac IRI, but the mechanism is still insufficiently understood.

METHODS

In vivo, myocardial ischemia/reperfusion (30 minutes/120 minutes) was induced via ligation and then reperfusion of the left anterior descending coronary artery (LAD) in mice. Intravenous infusion of 10 μg/kg DEX was performed 20 minutes before ligation. Moreover, the α2-adrenoreceptor antagonist Yohimbine and STAT3 inhibitor Stattic were applied 30 minutes ahead of DEX infusion. In vitro, hypoxia/reoxygenation (H/R) with DEX pretreatment for 1 hour was performed in isolated neonatal rat cardiomyocytes. In addition, Stattic was applied before DEX pretreatment.

RESULTS

In the mouse cardiac ischemia/reperfusion model, DEX pretreatment lowered the serum creatine kinase-MB isoenzyme (CK-MB) levels (2.47 ± 0.165 vs 1.55 ± 0.183; P < .0001), downregulated the inflammatory response ( P ≤ .0303), decreased 4-hydroxynonenal (4-HNE) production and cell apoptosis ( P = .0074), and promoted the phosphorylation of STAT3 (4.94 ± 0.690 vs 6.68 ± 0.710, P = .0001), which could be blunted by Yohimbine and Stattic. The bioinformatic analysis of differentially expressed mRNAs further confirmed that STAT3 signaling might be involved in the cardioprotection of DEX. Upon H/R treatment in isolated neonatal rat cardiomyocytes, 5 μM DEX pretreatment improved cell viability ( P = .0005), inhibited reactive oxygen species (ROS) production and calcium overload (both P ≤ .0040), decreased cell apoptosis ( P = .0470), and promoted STAT3 phosphorylation at Tyr705 (0.102 ± 0.0224 vs 0.297 ± 0.0937; P < .0001) and Ser727 (0.586 ± 0.177 vs 0.886 ± 0.0546; P = .0157), which could be abolished by Stattic.

CONCLUSIONS

DEX pretreatment protects against myocardial IRI, presumably by promoting STAT3 phosphorylation via the α2-adrenoreceptor in vivo and in vitro.

Tackling regulated cell death yields enhanced protection in lung grafts

Background: Effective preservation strategies to ameliorate lung graft ischaemia injury are needed to rescue 'extended criteria' or 'marginal' lung grafts, and to improve recipient outcomes after transplantation. Methods: Lung grafts from male Lewis rats were extracted after 40 min of cardiocirculatory death, and healthy human lung tissues were collected from patients undergoing a lobectomy. Lung samples were then preserved in a 4°C preservation solution supplemented with 0.1 nM Dexmedetomidine (Dex, α2-adrenoceptor agonist) for 16 h. In vitro, human lung epithelial A549 cells were preserved in the 4°C preservation solution with 0.1 nM Dex for 24 h, then re-cultured in the cell culture medium at 37°C to mimic the clinical scenario of cold ischaemia and warm reperfusion. Lung tissues and cells were then analysed with various techniques including western blot, immunostaining and electron microscope, to determine injuries and the protection of Dex. Results: Prolonged warm ischaemia after cardiocirculatory death initiated Rip kinase-mediated necroptosis, which was exacerbated by cold storage insult and enhanced lung graft injury. Dex supplementation significantly reduced necroptosis through upregulating Nrf2 activation and reducing oxidative stress, thereby significantly improving lung graft morphology. Dex treatment also attenuated endoplasmic reticulum stress, stabilised lysosomes and promoted cell membrane resealing function, consequently reducing cell death and inflammatory activation after hypothermic hypoxia-reoxygenation in A549 cells. Conclusions: Inhibition of regulated cell death through Dex supplementation to the graft preservation solution improves allograft quality which may aid to expand the donor lung pool and enhance lung transplant outcomes per se.

Inhibition of the JAK/STAT Pathway With Baricitinib Reduces the Multiple Organ Dysfunction Caused by Hemorrhagic Shock in Rats

OBJECTIVE

The aim of this study was to investigate (a) the effects of the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway inhibitor (baricitinib) on the multiple organ dysfunction syndrome (MODS) in a rat model of hemorrhagic shock (HS) and (b) whether treatment with baricitinib attenuates the activation of JAK/STAT, NF-κB, and NLRP3 caused by HS.

BACKGROUND

Posttraumatic MODS, which is in part due to excessive systemic inflammation, is associated with high morbidity and mortality. The JAK/STAT pathway is a regulator of numerous growth factor and cytokine receptors and, hence, is considered a potential master regulator of many inflammatory signaling processes. However, its role in trauma-hemorrhage is unknown.

METHODS

An acute HS rat model was performed to determine the effect of baricitinib on MODS. The activation of JAK/STAT, NF-κB, and NLRP3 pathways were analyzed by western blotting in the kidney and liver.

RESULTS

We demonstrate here for the first time that treatment with baricitinib (during resuscitation following severe hemorrhage) attenuates the organ injury and dysfunction and the activation of JAK/STAT, NF-κB, and NLRP3 pathways caused by HS in the rat.

CONCLUSIONS

Our results point to a role of the JAK/STAT pathway in the pathophysiology of the organ injury and dysfunction caused by trauma/hemorrhage and indicate that JAK inhibitors, such as baricitinib, may be repurposed for the treatment of the MODS after trauma and/or hemorrhage.

Correlation between perioperative dexmedetomidine administration and postoperative acute kidney injury in hypertensive patients undergoing non-cardiac surgery

Background: Previous studies have suggested that dexmedetomidine may have a protective effect on renal function. However, it is currently unclear whether perioperative dexmedetomidine administration is associated with postoperative acute kidney injury (AKI) incidence risk in hypertensive patients undergoing non-cardiac surgery.

Methods: This investigation was a retrospective cohort study. Hypertensive patients undergoing non-cardiac surgery in Third Xiangya Hospital of Central South University from June 2018 to December 2019 were included. The relevant data were extracted through electronic cases. The univariable analysis identified demographic, preoperative laboratory, and intraoperative factors associated with acute kidney injury. Multivariable stepwise logistic regression was used to assess the association between perioperative dexmedetomidine administration and postoperative acute kidney injury after adjusting for interference factors. In addition, we further performed sensitivity analyses in four subgroups to further validate the robustness of the results.

Results: A total of 5769 patients were included in this study, with a 7.66% incidence of postoperative acute kidney injury. The incidence of postoperative acute kidney injury was lower in the dexmedetomidine-administered group than in the control group (4.12% vs. 8.06%, p &lt; 0.001). In the multivariable stepwise logistic regression analysis, perioperative dexmedetomidine administration significantly reduced the risk of postoperative acute kidney injury after adjusting for interference factors [odds ratio (OR) = 0.56, 95% confidence interval (CI): 0.36–0.87, p = 0.010]. In addition, sensitivity analysis in four subgroups indicated parallel findings: i) eGRF &lt;90 mL/min·1.73/m2 subgroup (OR = 0.40, 95% CI: 0.19–0.84, p = 0.016), ii) intraoperative blood loss &lt;1000 mL subgroup (OR = 0.58, 95% CI: 0.36–0.94, p = 0.025), iii) non-diabetes subgroup (OR = 0.51, 95% CI: 0.29–0.89, p = 0.018), and iv) older subgroup (OR = 0.55, 95% CI: 0.32–0.93, p = 0.027).

Conclusion: In conclusion, our study suggests that perioperative dexmedetomidine administration is associated with lower risk and less severity of postoperative acute kidney injury in hypertensive individuals undergoing non-cardiac surgery. Therefore, future large-scale RCT studies are necessary to validate this benefit.

Influence of Dexmedetomidine on Myocardial Injury in Patients with Simultaneous Pancreas-Kidney Transplantation

Background

Diabetes is one of the most common chronic diseases in the world. End-stage renal disease (ESRD) caused by diabetes is the most serious long-term complication. The main cause of death in patients with simultaneous pancreas-kidney transplantation (SPKT) is cardiovascular disease. Although dexmedetomidine (Dex) has unique advantages in heart protection against ischaemic/reperfusion injury, few clinical studies have been conducted on its cardioprotective effect in SPKT. This study aimed to explore the influence of Dex on myocardial injury in patients undergoing SPKT and to analyze its possible mechanism.

Methods

A randomized controlled trial (RCT) was performed from July 1, 2018 to December 1, 2020. Eighty patients, regardless of gender, scheduled for SPKT were randomly allocated into a Dex group (D group) receiving Dex at a rate of 1 µg/kg for 10 minutes before anaesthesia induction and then continuous infusion at 0.5 µg/kg/hour until the end of surgery and control group (C group) receiving equivalent capacity of saline. Serum cardiac troponin I (cTnI), creatine kinase isoenzyme (CK-MB), tumour necrosis factor-α (TNF-α), and interleukin-6 (IL-6) were recorded at 5 minutes after anaesthesia induction (baseline,T0), 5 minutes before renal arteriovenous opening (T1), 30 minutes after renal arteriovenous opening (T2), 30 minutes after pancreatic related arteriovenous opening (T3), immediately after surgery (T4), 4 hours after surgery (T5), and 24 hours after surgery (T6). Adverse cardiovascular events were recorded during the perioperative period. Changes in ECG S-T segments and T waves were monitored at T0-T6. Myocardial infarction and percutaneous coronary intervention were recorded with an average follow-up of one year.

Results

Compared with T0, TNF-α and IL-6 concentrations significantly increased at T1-T6 in the C and D groups (P < 0.05). IL-6 concentration increased significantly after renal artery opening and reached the peak after the opening of pancreatic blood vessels. Compared with the C group, TNF-α, and IL-6 concentrations were significantly reduced in group D at T2-T6 (P < 0.05). Compared with T0, cTnI and CK-MB concentrations were significantly increased at T3-T6 in the C and D groups (P < 0.05). cTnI and CK-MB concentrations increased significantly after the opening of renal artery, and reached the peak after the opening of pancreatic blood vessels. Compared with the C group, cTnI and CK-MB concentrations were significantly reduced in the D group at T3-T6 (P < 0.05). There was no significant difference in patient characteristics amongst groups, including the proportion of intraoperative vasoactive drug use and adverse cardiovascular events during the follow-up period. Heart rate, mean blood pressure, central venous pressure, and cardiac output were not remarkably different between the two groups at any time point.

Conclusions

Perioperative reperfusion could aggravate myocardial injury in SPKT. Dex may be considered a way to reduce myocardial injury caused by inflammatory action by decreasing the release of inflammatory factors. Trial Registration Number: Chinese Clinical Trial Registry ID: ChiCTR2200060084.

Pioglitazone modulates immune activation and ameliorates inflammation induced by injured renal tubular epithelial cells via PPARγ/miRNA‑124/STAT3 signaling

Acute kidney injury (AKI) is commonly a result of renal ischemia reperfusion injury (IRI), which produces clinical complications characterized by the rapid deterioration of renal function, leading to chronic kidney disease and increases the risk of morbidity and mortality. Currently, only supportive treatment is available. AKI, which is accompanied by immune activation and inflammation, is caused by proximal tubular injury. The present study investigated the role of tubular epithelial cells as drivers of inflammation in renal IRI and their potential function as antigen-presenting cells, as well as the molecular mechanisms by which peroxisome proliferator-activated receptor-γ (PPARγ) agonists [such as pioglitazone (Pio)] exert reno-protective action in renal IRI. A total of 50 Wistar male albino rats were divided into five groups: Sham + DMSO, Sham + Pio, IRI + DMSO, IRI + prophylactic preoperative (pre) Pio and IRI + postoperative Pio. The histopathological changes in renal tissue samples and the renal epithelial cell expression of CD86, miRNA-124, STAT3, pro-inflammatory cytokines, inducible nitric oxide synthase (iNOS) and Arginase-II were analyzed by immunohistochemistry, reverse transcription-quantitative PCR, western blotting and ELISA respectively. IRI was a potent inducer for CD86 immunoexpression. An ameliorative action of Pio was demonstrated via decreased CD86 immunoexpression, upregulation of miRNA-124, decreased STAT3 expression and beneficial anti-inflammatory effects. The tubular epithelium served a notable role in the inflammatory response in renal IRI. Pio exerted its anti-inflammatory effects via PPARγ/miRNA-124/STAT3 signaling.

Dexmedetomidine attenuates renal ischemia-reperfusion injury through activating PI3K/Akt-eNOS signaling via α2 adrenoreceptors in renal microvascular endothelial cells

Renal microvascular endothelial cells (RMECs), which are closely related to regulation of vascular reactivity and modulation of inflammation, play a crucial role in the process of renal ischemia and reperfusion (I/R) injury. Previous studies have reported the protective effects of dexmedetomidine (DEX) against renal I/R injury, but little is known about the role of DEX on RMECs. This study aimed to investigate whether DEX alleviated renal I/R injury via acting on the RMECs. Mice underwent bilateral renal artery clamping for 45 min followed by reperfusion for 48 h, and the cultured neonatal mice RMECs were subjected to hypoxia for 1 h followed by reoxygenation (H/R) for 24 h. The results suggest that DEX alleviated renal I/R injury in vivo and improved cell viability of RMECs during H/R injury in vitro. Gene sequencing revealed that the PI3K/Akt was the top enriched signaling pathway and the endothelial cells were widely involved in renal I/R injury. DEX activated phosphorylation of PI3K and Akt, increased eNOS expression, and attenuated inflammatory responses. In addition, the results confirmed the distribution of α₂ adrenoreceptor (α₂ -AR) in RMECs. Furthermore, the protective effects of DEX against renal I/R injury were abolished by α₂ -AR antagonist (atipamezole), which was partly reversed by the PI3K agonist (740 Y-P). These findings indicated that DEX protects against renal I/R injury by activating the PI3K/Akt-eNOS pathway and inhibiting inflammation responses via α₂ -AR in RMECs.

Dexmedetomidine Attenuates Ferroptosis-Mediated Renal Ischemia/Reperfusion Injury and Inflammation by Inhibiting ACSL4 via α2-AR

Ischemia-reperfusion (I/R) injury is a serious clinical pathology associated with acute kidney injury (AKI). Ferroptosis is non-apoptotic cell death that is known to contribute to renal I/R injury. Dexmedetomidine (Dex) has been shown to exert anti-inflammatory and organ protective effects. This study aimed to investigate the detailed molecular mechanism of Dex protects kidneys against I/R injury through inhibiting ferroptosis. We established the I/R-induced renal injury model in mice, and OGD/R induced HEK293T cells damage in vitro. RNA-seq analysis was performed for identifying the potential therapeutic targets. RNA-seq analysis for differentially expressed genes (DEGs) reported Acyl-CoA synthetase long-chain family member 4 (ACSL4) related to ferroptosis and inflammation in I/R mice renal, which was validated in rodent renal. Liproxstatin-1, the specific small-molecule inhibitor of ferroptosis, significantly attenuated ferroptosis-mediated renal I/R injury with decreased LPO, MDA, and LDH levels, and increased GSH level. Inhibiting the activity of ACSL4 by the Rosiglitazone (ROSI) resulted in the decreased ferroptosis and inflammation, as well as reduced renal tissue damage, with decreasing LPO, MDA and LDH level, increasing GSH level, reducing COX2 and increasing GPx4 protein expression, and suppressing the TNF-α mRNA and IL-6 mRNA levels. Dex as a α2-adrenergic receptor (α2-AR) agonist performed renal protective effects against I/R-induced injury. Our results also revealed that Dex administration mitigated tissue damage, inhibited ferroptosis, and downregulated inflammation response following renal I/R injury, which were associated with the suppression of ACSL4. In addition, ACSL4 overexpression abolishes Dex-mediated protective effects on OGD/R induced ferroptosis and inflammation in HEK293T cells, and promotion of ACSL4 expression by α2-AR inhibitor significantly reversed the effects on the protective role of Dex. This present study indicated that the Dex attenuates ferroptosis-mediated renal I/R injury and inflammation by inhibiting ACSL4 via α2-AR.

Plants with Therapeutic Potential for Ischemic Acute Kidney Injury: A Systematic Review

Acute kidney injury (AKI) is a complex condition which has an intricate pathology mostly involving hemodynamic, inflammatory, and direct toxic effects at the cellular level with high morbidity and mortality ratios. Renal ischemic reperfusion injury (RIRI) is the main factor responsible for AKI, most often observed in different types of shock, kidney transplantation, sepsis, and postoperative procedures. The RIRI-induced AKI is accompanied by increased reactive oxygen species generation together with the activation of various inflammatory pathways. In this context, plant-derived medicines have shown encouraging nephroprotective properties. Evidence provided in this systemic review leads to the conclusion that plant-derived extracts and compounds exhibit nephroprotective action against renal ischemic reperfusion induced-AKI by increasing endogenous antioxidants and decreasing anti-inflammatory cytokines. However, there is no defined biomarker or target which can be used for treating AKI completely. These plant-derived extracts and compounds are only tested in selected transgenic animal models. To develop the results obtained into a therapeutic entity, one should apply them in proper vertebrate multitransgenic animal models prior to further validation in humans.

Effect of dexmedetomidine administration on analgesic, respiration and inflammatory responses in patients undergoing percutaneous endoscopic lumbar discectomy: a prospective observational study

Background

Local anesthesia has been recommended for percutaneous endoscopic lumbar discectomy (PELD) in recent years; however, the efficacy, including oxidative stress, inflammatory reactions and ventilation effects, when intravenous dexmedetomidine (DEX) is administered during PELD has not been described.

Methods

Sixty adult patients undergoing PELD were randomly allocated to either an intravenous DEX sedation group (Group A) or a normal saline group (Group B). Respiratory data, including minute ventilation (MV), tidal volume (TV), and respiratory rate (RR), were recorded using a respiratory volume monitor (RVM), and peripheral oxygen saturation (SpO₂) was monitored by pulse oximetry. The visual analog score (VAS) was used to assess the level of pain. The serum levels of inflammatory biomarkers including interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were to assess inflammatory reactions. The serum levels of oxidative stress biomarkers including malondialdehyde (MDA) and glutathione peroxidase (GSH-PX) were also recorded to evaluate oxidative stress.

Results

There were no significant differences in RR, MV, TV and SpO₂ between the two groups at any time point (P > 0.05). Group B exhibited lower serum levels of GSH-PX (P < 0.0001) and higher serum levels of MDA (p < 0.0001) than Group A at the end of surgery. Twenty-four hours after surgery, Group B exhibited higher serum levels of IL-6 (P = 0.0033), TNF-α (P = 0.0002), and MDA (P < 0.0001) and lower serum levels of GSH-PX (P < 0.0001) than Group A. In addition, Group A exhibited lower VAS (P < 0.0001) than Group B during surgery.

Conclusions

DEX administration using RVM not only provides analgesia without ventilatory depression but also alleviates oxidative stress and inflammatory reactions in patients undergoing PELD.

Angiotensin1-7 Protects Against Renal Ischemia-Reperfusion Injury via Regulating the Expression of NRF2 and microRNAs in Fisher 344 Rats

Ischemia/reperfusion (I/R) is considered the primary cause of acute kidney injury and is higher among older individuals. While ischemic episodes are hard to predict and prevent, detrimental ischemic effects could be mitigated by exogenous intervention. This study aims to identify the protective role of angiotensin (ANG)1-7 against I/R-induced renal injury in adult vs. aged rats. Adult and aged male Fisher 344 rats were subjected to 40-minute bilateral renal ischemia followed by 28-days reperfusion. ANG1-7 was administered intraperitoneally in ischemic rats for 28 days without or with Mas receptor antagonist A779. I/R increased blood pressure, plasma creatinine, urinary 8-isoprostane, and renal infiltration of pro and anti-inflammatory macrophages and reduced glomerular filtration rate in both adult and aged rats compared to shams. In addition to causing glomerular sclerosis and tubular damage, I/R increased the expression of pathogenic microRNAs (miRNAs): miR-20a-5p, miR-21-5p, miR-24-3p, and miR-194-5p in both the age groups. ANG1-7 treatment of ischemic rats mitigated oxidative stress and renal inflammation, restored renal structure and function, and reduced high blood pressure. Also, ANG1-7 suppressed the expression of pathogenic miRNAs. In addition, ANG1-7 treatment of I/R rats increased the expression of redox-sensitive transcription factor NRF2 and phase II antioxidant enzymes. The beneficial effects of ANG1-7 were sensitive to A779. Collectively, these data suggest that ANG1-7 associated with NRF2 activation could alleviate post-I/R-induced kidney injury and therefore serve as a potential therapeutic compound to protect against biochemical and morphological pathologies of I/R in both adults and aged populations.

Prevention of dexmedetomidine on postoperative delirium and early postoperative cognitive dysfunction in elderly patients undergoing hepatic lobectomy

OBJECTIVES

Postoperative delirium (POD) and postoperative cognitive dysfunction (POCD) are common operative neurocognitive disorders, which places a heavy burden on patients, families and society. Therefore, it is very important to search for preventive drugs. Previous studies have demonstrated that perioperative use of dexmedetomidine resulted in a decrease the incidence of POD and POCD. But the specific effect of dexmedetomidine on elderly patients undergoing hepatic lobectomy and its potential mechanism are not clear. This study aims to evaluate the efficacy of intraoperative use of dexmedetomidine on preventing POD and POCD in elderly patients undergoing hepatic lobectomy and the influence on the balance between proinflammation and anti-inflammation.

METHODS

This trial was designed as a single-center, prospective, randomized, controlled study. One hundred and twenty hospitalized patients from January 2019 to December 2020, aged 60-80 years old with American Society of Anesthesiologists (ASA) II-III and scheduled for hepatic lobectomy, were randomly allocated into 3 groups (n=40) using a random number table: A C group, a Dex1 group, and a Dex2 group. After anesthesia induction, saline in the C group, dexmedetomidine [0.3 μg/(kg·h)] in the Dex1 group, and dexmedetomidine [0.6 μg/(kg·h)] in the Dex2 group were infused until the end of operation. The incidences of hypotension and bradycardia were compared among the 3 groups. Confusion Assessment Method (CAM) for assessing POD and Mini Mental State Examination (MMSE) for evaluating POCD were recorded and venous blood samples were obtained for the determination of neuron specific enolase (NSE), TNF-α, IL-1β, and IL-10 at the different time below: the time before anesthesia (T0), and the first day (T1), the third day (T2), the fifth day (T3), and the seventh day (T4) after operation.

RESULTS

Compared with the C group, the incidences of bradycardia in the Dex1 group or the Dex2 group increased (both P<0.05) and there was no difference in hypotension in the Dex1 group or the Dex2 group (both P>0.05). The incidences of POD in the C group, the Dex1 group, and the Dex2 group were 22.5%, 5.0%, and 7.5%, respectively. The incidences of POD in the Dex1 group or the Dex2 group declined significantly as compared to the C group (both P<0.05). However, there is no difference in the incidence of POD between the Dex1 group and the Dex2 group (P>0.05). The incidences of POCD in the C group, the Dex1 group, and the Dex2 group were 30.0%, 12.5%, and 10.0%, respectively. The incidences of POCD in the Dex1 group and the Dex2 group declined significantly as compared to the C group (both P<0.05). And no obvious difference was seen in the incidence of POCD in the Dex1 group and the Dex2 group (P>0.05). Compared with the C group, the level of TNF-α and IL-1β decreased and the level of IL-10 increased at each time points (from T1 to T4) in the Dex1 group and the Dex2 group (all P<0.05). Compared with the Dex1 group, the level of IL-1β at T2 and IL-10 from T1 to T3 elevated in the Dex2 group (all P<0.05). Compared with the T0, the concentrations of NSE in C group at each time points (from T1 to T4) and in the Dex1 group and the Dex2 group from T1 to T3 increased (all P<0.05). Compared with the C group, the level of NSE decreased from T1 to T4 in the Dex1 group and the Dex2 group (all P<0.05).

CONCLUSIONS

Intraoperative dexmedetomidine infusion can reduce the incidence of POCD and POD in elderly patients undergoing hepatic lobectomy, and the protective mechanism appears to involve the down-regulation of TNF-α and IL-1β and upregulation of IL-10 expression, which lead to rebalance between proinflammation and anti-inflammation.

Effect of interferon regulatory factor 2 on inflammatory response and oxidative stress in lipopolysaccharide-induced acute kidney injury

Interferon regulatory factor (IRF) 2 plays an important role in lipopolysaccharide (LPS)-induced acute kidney injury (AKI). In this study, we explored the effects of IRF2 on apoptosis, inflammation, and oxidative stress in AKI C57BL/6 male mouse model and HEK293 cells following LPS treatment. To determine the effect of IRF2, short hairpin RNAs in mice and small interfering RNAs in cells were used to knockdown IRF2 expression. IRF2 expression, apoptosis, and severity of inflammatory and oxidative stress in mice and cells were measured. IRF2 levels were upregulated in LPS-treated mice and cells. IRF2 knockdown suppressed the levels of creatinine, blood urea nitrogen, and kidney injury molecule 1 and decreased the renal injury score in mice. Furthermore, IRF2 knockdown inhibited apoptosis and decreased the levels of inflammatory, reactive oxygen species (ROS), and malondialdehyde (MDA), but increased superoxide dismutase (SOD) levels in mice and cells. Furthermore, we found that the Janus kinase (JAK)/ signal transducer and activator of transcription pathway activated by LPS was inhibited by knockdown of IRF2, and enhanced by IRF2 overexpression. IRF2 overexpression increased cell apoptosis, inflammation, and ROS and MDA levels, and decreased SOD levels. However, the effect of IRF2 overexpression was reversed by the JAK inhibitor tofacitinib. Knockdown of IRF2 reduced LPS-induced renal tissue injury in vivo and in vitro through anti-inflammatory and antioxidant stress effects.

JAK2/STAT3 inhibition attenuates intestinal ischemia-reperfusion injury via promoting autophagy: in vitro and in vivo study

BACKGROUND

Intestinal ischemia-reperfusion (I/R) causes severe injury to the intestine, leading to systemic inflammation and multiple organ failure. Autophagy is a stress-response mechanism that can protect against I/R injury by removing damaged organelles and toxic protein aggregates. Recent evidence has identified JAK-STAT signaling pathway as a new regulator of autophagy process, however, their regulatory relationship in intestinal I/R remains unknown.

METHODS AND RESULTS

We systematically analyzed intestinal transcriptome data and found that JAK-STAT pathway was largely activated in response to I/R with most significant upregulation observed for JAK2 and STAT3. ChIP-Seq and luciferase assays in an in vitro oxygen-glucose deprivation and reoxygenation model revealed that activated JAK2/STAT3 signaling directly inhibited the transcription of autophagy regulator Beclin-1, leading to the suppression of autophagy and the activation of intestinal cell death. These findings were further confirmed in an in vivo mouse model, in which, intestinal I/R injury was associated with the activation of JAK2/STAT3 pathway and the deactivation of Beclin-1-mediated autophagy, while inhibiting JAK2/STAT3 with AG490 reactivated autophagy and improved survival after intestinal I/R injury.

CONCLUSIONS

JAK2/STAT3 signaling suppresses autophagy process during intestinal I/R, while inhibiting JAK-STAT can be protective against intestinal I/R injury by activating autophagy. These findings expand our knowledge on intestinal I/R injury and provide therapeutic targets for clinical treatment.

JAK Inhibition Prevents DNA Damage and Apoptosis in Testicular Ischemia-Reperfusion Injury via Modulation of the ATM/ATR/Chk Pathway

Testicular ischemia reperfusion injury (tIRI) causes oxidative stress-induced DNA damage leading to germ cell apoptosis (GCA). The aim of the study is to establish a direct link between JAK2 activation and the DNA damage response (DDR) signaling pathways and their role in tIRI-induced GCA using AG490, a JAK2 specific inhibitor. Male Sprague Dawley rats (n = 36) were divided into three groups: sham, unilateral tIRI and tIRI + AG490 (40 mg/kg). During tIRI, augmentation in the phosphorylation levels of the JAK2/STAT1/STAT3 was measured by immunohistochemistry. Observed spermatogenic arrest was explained by the presence of considerable levels of DSB, AP sites and 8OHdG and activation of caspase 9, caspase 3 and PARP, which were measured by colorimetric assays and TUNEL. The ATM/Chk2/H2AX and ATR/Chk1 pathways were also activated as judged by their increased phosphorylation using Western blot. These observations were all prevented by AG490 inhibition of JAK2 activity. Our findings demonstrate that JAK2 regulates tIRI-induced GCA, oxidative DNA damage and activation of the ATM/Chk2/H2AX and ATR/Chk1 DDR pathways, but the cell made the apoptosis decision despite DDR efforts.

Cardiac Surgery Associated AKI Prevention Strategies and Medical Treatment for CSA-AKI

Acute kidney injury (AKI) is common after cardiac surgery. To date, there are no specific pharmacological therapies. In this review, we summarise the existing evidence for prevention and management of cardiac surgery-associated AKI and outline areas for future research. Preoperatively, angiotensin-converting enzyme inhibitors and angiotensin receptor blockers should be withheld and nephrotoxins should be avoided to reduce the risk. Intraoperative strategies include goal-directed therapy with individualised blood pressure management and administration of balanced fluids, the use of circuits with biocompatible coatings, application of minimally invasive extracorporeal circulation, and lung protective ventilation. Postoperative management should be in accordance with current KDIGO AKI recommendations.

Effect of ondansetron on reducing ICU mortality in patients with acute kidney injury

The purpose of this study is to identify medications with potentially beneficial effects on decreasing mortality in patients with acute kidney injury (AKI) while in the intensive care unit (ICU). We used logistic regression to investigate associations between medications received and ICU mortality in patients with AKI in the MIMIC III database. Drugs associated with reduced mortality were then validated using the eICU database. Propensity score matching (PSM) was used for matching the patients’ baseline severity of illness followed by a chi-square test to calculate the significance of drug use and mortality. Finally, we examined gene expression signatures to explore the drug’s molecular mechanism on AKI. While several drugs demonstrated potential beneficial effects on reducing mortality, most were used for potentially fatal illnesses (e.g. antibiotics, cardiac medications). One exception was found, ondansetron, a drug without previously identified life-saving effects, has correlation with lower mortality among AKI patients. This association was confirmed in a subsequent analysis using the eICU database. Based on the comparison of gene expression signatures, the presumed therapeutic effect of ondansetron may be elicited through the NF-KB pathway and JAK-STAT pathway. Our findings provide real-world evidence to support clinical trials of ondansetron for treatment of AKI.

Dexmedetomidine reduces acute kidney injury after endovascular aortic repair of Stanford type B aortic dissection: A randomized, double-blind, placebo-controlled pilot study

STUDY OBJECTIVE

To determine the effect of dexmedetomidine on acute kidney injury (AKI) following endovascular aortic repair (EVAR) for Stanford type B aortic dissection (TBAD).

DESIGN

Randomized, double-blind, placebo-controlled, pilot study.

SETTING

University Hospital.

PATIENTS

102 TBAD patients undergoing EVAR procedures were enrolled. Patients with dissection involving aortic arch or renal artery were excluded.

INTERVENTIONS

Patients were randomly assigned, in a 1:1 ratio, to a dexmedetomidine group (intravenous dexmedetomidine 0.4 μg/kg/h immediately after anesthesia induction and 0.1 μg/kg/h after extubation, which was maintained until 24 h) or a normal saline control group.

MEASUREMENTS

The primary outcome was the incidence of AKI within the first two days after surgery, based on the Acute Kidney Injury Network (AKIN) criteria. The secondary outcomes included serum cystatin C and estimated glomerular filtration rate on postoperative days 1, 2, and 7, and in-hospital need for renal replacement therapy (RRT). Long-term outcomes included RRT and all-cause mortality.

MAIN RESULTS

Ninety-eight patients completed the study (dexmedetomidine, n = 48; control, n = 50). AKIN stage 1 AKI occurred in 3/48 (6.3%) patients receiving dexmedetomidine, compared with 11/50 (22%) patients receiving normal saline (odds ratio = 0.24, 95% CI: 0.07 to 0.89, P = 0.041). This difference remained significant after adjusting for baseline covariates (adjusted odds ratio = 0.21, 95% CI: 0.05 to 0.84; P = 0.028). Dexmedetomidine led to a lower serum cystatin C on postoperative day 1 (median [IQR] mg/L: 1.31 [1.02-1.72] vs. 1.58 [1.28-1.96]). There were no between-group differences in other secondary or long-term outcomes. During the follow-up (median = 28.4 months), 1 patient in the dexmedetomidine group and 3 patients in the control group required RRT.

CONCLUSIONS

Dexmedetomidine reduced the incidence of AKI in TBAD patients after EVAR procedures. The long-term benefits of dexmedetomidine in this patient population warrant further investigation.

TRIAL REGISTRATION

ChiCTR-IPR-15006372.

Dexmedetomidine Inhibited Proliferation and Invasion of Cervical Cancer Cells by Inhibiting the Janus Tyrosine Kinase/Signal Transducer and Activator of Transcription Signaling Pathway

The role of anesthetics in the treatment of cancer has been reported, but the role of Dexmedetomidine (Dex) in the treatment of cervical cancer (CC) has not been reported.In this study, cell viability and proliferation were determined by MTT and cloning formation assay. The expression of proliferation-related proteins ki67 and PCNA was detected by western blot. Wound healing and transwell detected cell migration and invasion, and western blot detected the expression of migration and invasion related proteins MMP4 and MMP9, and epithelial-mesenchymal transformation (ETM)-related proteins N-cadherin, Snail, Vimentin and E-cadherin. Western blot also detected the expression of pathway related proteins p-JAK2, p-STAT1, p-STAT3, JAK2, STAT1 and STAT3. It showed that Dex inhibited the cell viability and proliferation of Hela and siHa and the expression of ki67 and PCNA were also inhibited. Dex inhibited the cell migration and invasion, and inhibited the expression of MMP4 and MMP9. In addition, Dex inhibited the expression of N-cadherin, Snail and Vimentin, and promoted the expression of E-cadherin. Dex inhibited the expression of p-JAK2, p-STAT1 and p-STAT3. After the addition of JAK/STAT signaling pathway agonist IL-6, the inhibition of Dex on proliferation, migration and invasion of CC cells was reversed. And the addition of JAK/STAT signaling pathway inhibitor AG490 could counteract the excitatory effect of IL-6 on the pathway, at which time the cell proliferation, invasion and migration were significantly increased. In conclusion, our study demonstrated that Dex inhibited proliferation, migration, and invasion of cells in CC by blocking the JAK/STAT signaling pathway.

LINGO-1 shRNA protects the brain against ischemia/reperfusion injury by inhibiting the activation of NF-κB and JAK2/STAT3

LINGO-1 may be involved in the pathogenesis of cerebral ischemia. However, its biological function and underlying molecular mechanism in cerebral ischemia remain to be further defined. In our study, middle cerebral artery occlusion/reperfusion (MACO/R) mice model and HT22 cell oxygen–glucose deprivation/reperfusion (OGD/R) were established to simulate the pathological process of cerebral ischemia in vivo and in vitro and to detect the relevant mechanism. We found that LINGO-1 mRNA and protein were upregulated in mice and cell models. Down-regulation LINGO-1 improved the neurological symptoms and reduced pathological changes and the infarct size of the mice after MACO/R. In addition, LINGO-1 interference alleviated apoptosis and promoted cell proliferation in HT22 of OGD/R. Moreover, down-regulation of LINGO-1 proved to inhibit nuclear translocation of p-NF-κB and reduce the expression level of p-JAK2 and p-STAT3. In conclusion, our data suggest that shLINGO-1 attenuated ischemic injury by negatively regulating NF-KB and JAK2/STAT3 pathways, highlighting a novel therapeutic target for ischemic stroke.

Effects of dexmedetomidine on renal microcirculation in ischemia/reperfusion-induced acute kidney injury in rats

Microcirculatory dysfunction plays a crucial role in renal ischemia/reperfusion (IR)-induced injury. Dexmedetomidine was reported to ameliorate IR-induced acute kidney injury. This study investigated the effects of dexmedetomidine on renal microcirculation after IR-induced acute kidney injury in rats. In total, 50 rats were randomly allocated to the following five groups (10 in each group): Sham, Control‒IR, Dex (dexmedetomidine) ‒Sham, Dex‒IR, and IR‒Dex group. The microcirculation parameters included total small vessel density, perfused small vessel density (PSVD), proportion of perfused small vessels, microvascular flow index, and tissue oxygen saturation (StO₂) were recorded. The repeated measures analysis showed that PSVD on renal surface was higher in the Dex‒IR group than in the Control‒IR group (3.5 mm/mm², 95% confidence interval [CI] 0.6 to 6.4 mm/mm², P = 0.01). At 240 min, StO₂ on renal surface was lower in the Control‒IR group than in the Sham group (– 7%, 95% CI − 13 to − 1%, P = 0.021), but StO₂ did not differ significantly among the Sham, Dex‒IR, and IR‒Dex groups. Our results showed that pretreatment with dexmedetomidine improved renal microcirculation in rats with IR-induced acute kidney injury. However, the adverse effects of low mean arterial pressure and heart rate might offset the protective effect of dexmedetomidine on organ injury.

Desflurane protects against liver ischemia/reperfusion injury via regulating miR-135b-5p

BACKGROUND

A number of anesthetics have protective effect against ischemia-reperfusion (I/R) injury, including desflurane. But the function and molecular mechanism of desflurane in liver I/R injury have not been fully understood. The aim of this study was to investigate the effect of desflurane on liver I/R injury and further investigated the molecular mechanisms involving in miR-135b-5p.

METHODS

The models of liver I/R injury in rats were established, and received desflurane treatment throughout the injury. Serum alanine transaminase (ALT) and aspartate transaminase (AST) were measured and compared between groups. H/R-induced cell model in L02 was established, and were treated with desflurane before hypoxia. Quantitative real-time polymerase chain reaction was performed to determine the expression of miR-135b-5p in different groups. The cell apoptosis was detected using flow cytometry assay. Western blot was used for the measurement of protein levels.

RESULTS

I/R significantly increased serum levels of ALT and AST in rats, which were reversed by desflurane treatment. Desflurane also significantly attenuated the increase of cell apoptosis induced by I/R in both vivo and vitro. MiR-135b-5p significantly reversed the protective effect of desflurane against liver I/R injury. Additionally, Janus protein tyrosine kinase (JAK)2 was shown to be a target gene of miR-135b-5p, and miR-135b-5p overexpression significantly decreased the protein levels of p-JAK2, JAK2, p-STAT3.

CONCLUSION

Desflurane attenuated liver I/R injury through regulating miR-135b-5p, and JAK2 was the target gene of mIR-135b-5p. These findings provide references for further development of therapeutic strategies in liver injury.

Protective effect of cordycepin on experimental renal ischemia/reperfusion injury in rats

AIM

To date, various molecules have been investigated to reduce the effect of renal ischemia/reperfusion (I/R) injury. However, none have yet led to clinical use. The present study aimed to investigate the protective effect of cordycepin (C) on renal I/R injury in an experimental rat model.

MATERIALS AND METHODS

Twenty-four mature Sprague Dawley female rat was randomly divided into three groups: Sham, I/R, I/R+C. All animals underwent abdominal exploration. To induce I/R injury, an atraumatic vascular bulldog clamp was applied to the right renal pedicle for 60 minutes (ischemia) and later clamp was removed to allow reperfusion in all rats, except for the sham group. In the I/R + C group, 10 mg/kg C was administered intraperitoneally, immediately after reperfusion. After 4 hours of reperfusion, the experiment was terminated with right nephrectomy. Histological studies and biochemical analyses were performed on the right nephrectomy specimens. EGTI (endothelial, glomerular, tubulointerstitial) histopathology scoring and semi-quantitative analysis of renal cortical necrosis were used for histological analyses and superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA), total oxidant status (TOS) for biochemical analyses.

RESULTS

Histopathological examination of the tissue damage revealed that all kidneys in the sham group were normal. The I/R group had higher histopathological scores than the I/R + C group. In the biochemical analysis of the tissues, SOD, MDA, TOS values were found to be statistically different in the I/R group compared to the I/R + C group (p: 0.004, 0.004, 0.001 respectively).

CONCLUSIONS

Intraperitoneal cordycepin injection following ischemia preserve renal tissue against oxidative stress in a rat model of renal I/R injury.

Efficacy and safety of dexmedetomidine in patients receiving mechanical ventilation: Evidence from randomized controlled trials

At present, the efficacy and safety of dexmedetomidine in patients receiving mechanical ventilation (MV) is still controversial. Therefore, the purpose of this research was to assess the efficacy and safety of dexmedetomidine in MV patients by reviewing the results of randomized controlled trials (RCT). RCTs evaluating the efficacy of dexmedetomidine in the treatment of MV patients were obtained by searching relevant online databases, including PubMed, EMbase, Web of Science, the Cochrane Library, Medline, OVID, and ClinicalTrials.gov. Literature meeting the inclusion criteria were selected and evaluated by two researchers independently. Risk ratio (RR)/standardized mean difference (SMD) and 95% confidence interval (CI) were used to express the differences between groups. Seven RCTs were included in our study, with 986 participants in the dexmedetomidine group and 862 participants in the control group. Summary analysis results displayed no reduction in 30-day mortality (RR = 0.77, 95% CI: 0.59 to 1.02), delirium (RR = 0.77, 95% CI: 0.57 to 1.03), and adverse events (RR = 1.06, 95% CI: 0.22 to 5.08) in the dexmedetomidine group compared with the control group. As the length of stay in the intensive care unit (ICU) were presented as median and interquartile range (IQR)/standard deviation (SD), descriptive analysis of the results were performed. Generally, for 99.65% (953/986) of patients, dexmedetomidine was not better than the control group in reducing ICU length of stay. Our results demonstrate that for patients requiring MV, dexmedetomidine was not superior to the control group. However, analysis of more RCTs is required to confirm this conclusion.

Protective effect of curcumin on busulfan-induced renal toxicity in male rats

AIM

The aim of this study was to evaluate the effects of curcumin in an experimental model of busulfan-induced renal toxicity with emphasis on importance of histological alterations.

METHODS

In this study, we utilized 32 adult male Wistar rats (250 ± 10 g). All the animals were divided into four experimental groups randomly: (I) Control; (II) Busulfan (40 mg/kg); (III) Olive oil; and (IV) Curcumin (80 mg/kg/day). Finally, the rats were euthanized and kidney tissues were taken for histopathology experiments, serum BUN, and creatinine level, reactive oxygen species (ROS) production and glutathione disulfide (GSH) activity.

RESULTS

Our result showed that the reduction in body weight and kidney weight in busulfan groups in comparison with the control and curcumin groups. The result in this study also showed that the reduction in BUN, creatinine, and ROS production in curcumin groups in comparison with the busulfan group together with an increasing of GSH activity compared to busulfan induced rats.

CONCLUSION

Our results of this study indicated that that the reduction in body weight, kidney weight, total volume of kidney, total length of nephron tubules, and numerical density of glomeruli and nephron tubules in busulfan groups in comparison with the control and curcumin groups However, curcumin can be an alternative choice for therapeutically and research purposes in the disturbing kidney after treatment with busulfan.

Umbelliferone attenuates gentamicin-induced renal toxicity by suppression of TLR-4/NF-κB-p65/NLRP-3 and JAK1/STAT-3 signaling pathways

Nephrotoxicity is the most common adverse effect of gentamicin (GNT). This study aimed to investigate the possible nephroprotective effect of umbelliferone (UMB), against GNT-induced nephrotoxicity. Rats were allocated into the control group; UMB group (50 mg/kg/day, P.O. for 15 days); GNT group (100 mg/kg/day, i.p., for 8 days); and GNT + UMB group. By the end of the experimental period, serum creatinine, urea, and uric acid as well as urine KIM-1 and urine albumin/creatinine ratio were evaluated to estimate kidney function. Moreover, tissue samples were collected for assessment of ERK1/2, p-ERK1/2, TLR-4, p38 MAPK, NF-κB-p65, NLRP-3, IkBα, TNF-α, IL-1β, JAK1, STAT-3, p-STAT, and cleaved caspase-3. In support, the histopathological examination of renal tissues was performed. UMB improves kidney function through regulation of renal serum biomarkers, with alleviations of histological abrasions induced by GNT. Besides, UMB downregulates renal protein expressions of ERK1/ERK2, TLR-4, and p38MAPK, with subsequent suppression of NF-κB-p65/NLRP-3 inflammasome and JAK1/STAT-3 pathways as well as cleaved caspase-3. In parallel, UMB induced IkBα upregulation. Collectively, UMB markedly amended all GNT-induced renal changes. These nephroprotective outcomes could be attributed to its ability to impede TLR-4/NF-κB-p65/NLRP-3 inflammasome and JAK1/STAT-3 pathways activation, as well as to its anti-inflammatory property.

Dexmedetomidine suppresses bupivacaine-induced parthanatos in human SH-SY5Y cells via the miR-7-5p/PARP1 axis-mediated ROS

This study aims to explore the regulatory mechanisms of dexmedetomidine in parthanatos. MTT assay was applied to reveal cell viability; JC-1 staining assay was utilized to reveal mitochondrial membrane potential. Reactive oxygen species (ROS) probe, DCFH-DA, was used to detect intracellular ROS production. Luciferase activity assay was applied to measure the binding between miR-7-5p and PARP1. We first identified that bupivacaine inhibited the viability and induced the parthanatos of human neuroblastoma SH-SY5Y cells. In addition, dexmedetomidine, a potent α2-adrenoceptor agonist, reversed the regulatory effect of bupivacaine on parthanatos of SH-SY5Y. More importantly, dexmedetomidine counteracted bupivacaine-induced changes of mitochondrial membrane potential and ROS production in SH-SY5Y cells. Hyper-activation of PARP1 plays a vital role in parthanatos. Further exploration of our study identified that bupivacaine triggered overexpression of PARP1 in SH-SY5Y cells. Bioinformatics analysis revealed that miR-7-5p targeted the 3' untranslated region (3' UTR) of PARP1 to inhibit PARP1 expression. In addition, dexmedetomidine recovered the suppressive effects of bupivacaine on miR-7-5p expression. Dexmedetomidine suppressed bupivacaine-induced parthanatos in SH-SY5Y cells via the miR-7-5p/PARP1 axis, which may shed a new insight into parthanatos-dependent neuronal injury.

Antioxidant effects of dexmedetomidine against hydrogen peroxide-induced DNA damage in vitro by alkaline Comet assay

Background/aim

Dexmedetomidine (DEX) is an alpha-2 adrenergic agonist that is commonly used as a sedative and anesthetic. The protective effects of DEX against oxidative damage under both in vitro and in vivo conditions have been demonstrated. It was aimed to evaluate and compare the protective effects of DEX and vitamin C (Vit C) on DNA against H₂O₂-induced DNA damage in human lymphocyte cell cultures in vitro by alkaline Comet assay.

Materials and methods

Lymphocyte cell cultures were divided into 5 groups, as the negative control, solvent control, positive control, hydrogen peroxide (H₂O₂; 150 μM) + DEX (1 μM; 2.5 μM; 5 μM), and H₂O₂ (150 μM) + Vit C (1 μM; 2.5 μM; 5 μM), and incubated at 37 °C for 1 h. Cell viability was measured using the Trypan blue test. DNA damage was measured using the Alkali Comet Technique and the % percent tail intensity was evaluated. Statistical analysis was performed using 1-way ANOVA and the Tukey multiple comparison test.

Results

It was observed that H₂O₂ significantly induced DNA damage in the lymphocytes and this damage was decreased significantly with Vit C and DEX. It was observed that Vit C at doses of 1 μM and 2.5 μM had a significantly stronger antioxidant effect, but there was no significant difference between the antioxidant effects of Vit C and DEX with a dose of 5 μM. The dose of 5 μM DEX was found to be the most effective in reducing oxidative DNA damage.

Conclusion

There is limited data on the protective effects of DEX against oxidative DNA damage. The primary effect might be cytoprotection. The results herein showed that DEX was protective against H₂O₂-induced in vitro oxidative DNA damage in lymphocyte cell cultures in a dose-dependent manner. DEX might have a potential therapeutic value in the prevention of oxidative DNA damage in patients.

Electroacupuncture Pretreatment Attenuates Intestinal Injury after Autogenous Orthotopic Liver Transplantation in Rats via the JAK/STAT Pathway

Background

Liver transplantation induces self-injury and affects remote organs, such as the lung, kidney, and intestine. Postoperative intestinal dysfunction has been associated with prolonged hospitalization and affects a patient's health and quality of life. Electroacupuncture (EA) has been proven effective in multiple organ protection. However, the potential mechanism underlying the protective effects of EA on intestinal injury after liver transplantation remains unclear.

Methods

After establishing an autogenous orthotopic liver transplantation (AOLT) model, we studied the effects of EA pretreatment on intestinal injury after AOLT. We used the JAK2-specific inhibitor AG490 to explore the underlying mechanism. Histological analysis and apoptosis assays were used to evaluate intestinal injury. Oxidative stress index and inflammatory response were also measured after AOLT. Furthermore, we detected the phosphorylation levels of JAK2, STAT1, and STAT3 by Western blot.

Results

We found that pretreatment with EA alleviated intestinal injury after AOLT, as shown by HE staining and TUNEL methods. EA pretreatment inhibited the expressions of p-JAK2, p-STAT1, and p-STAT3 in the intestines after AOLT. Upon treatment with JAK2-specific inhibitor AG490, intestinal injury was balanced.

Conclusion

The data indicated EA pretreatment alleviated intestinal injury after AOLT by inhibiting the JAK/STAT signaling pathway. These results provide basic evidence to support the potential therapeutic efficacy of EA.

Edaravone alleviates cell apoptosis and mitochondrial injury in ischemia-reperfusion-induced kidney injury via the JAK/STAT pathway

Background

Kidney ischemia–reperfusion injury is a common pathophysiological phenomenon in the clinic. A large number of studies have found that the tyrosine protein kinase/signal transducer and activator of transcription (JAK/STAT) pathway is involved in the development of a variety of kidney diseases and renal protection associated with multiple drugs. Edaravone (EDA) is an effective free radical scavenger that has been used clinically for the treatment of postischemic neuronal injury. This study aimed to identify whether EDA improved kidney function in rats with ischemia–reperfusion injury by regulating the JAK/STAT pathway and clarify the underlying mechanism.

Methods

Histomorphological analysis was used to assess pathological kidney injury, and mitochondrial damage was observed by transmission electron microscopy. Terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) staining was performed to detect tubular epithelial cell apoptosis. The expression of JAK2, P-JAK2, STAT3, P-STAT3, STAT1, P-STAT1, BAX and Bcl-2 was assessed by western blotting. Mitochondrial function in the kidney was assessed by mitochondrial membrane potential (ΔΨm) measurement.

Results

The results showed that EDA inhibited the expression of p-JAK2, p-STAT3 and p-STAT1, accompanied by downregulation of the expression of Bax and caspase-3, and significantly ameliorated kidney damage caused by ischemia–reperfusion injury (IRI). Furthermore, the JC-1 dye assay showed that edaravone attenuated ischemia–reperfusion-induced loss of kidney ΔΨm.

Conclusion

Our findings indicate that EDA protects against kidney damage caused by ischemia–reperfusion through JAK/STAT signaling, inhibiting apoptosis and improving mitochondrial injury.

Curcumin and LOXblock-1 ameliorate ischemia-reperfusion induced inflammation and acute kidney injury by suppressing the semaphorin-plexin pathway

AIMS

Ischemia/reperfusion (I/R) is one of the most important causes of acute kidney injury (AKI), a clinical syndrome with kidney dysfunction and high mortality rates. New diagnostic biomarkers need to be defined to better illuminate the pathophysiology of AKI. For the first time, we aim to investigate the protective effects of Curcumin which is known for its antioxidant and anti-inflammatory properties and 12/15 lipoxygenase inhibitor LOXblock-1 on I/R induced AKI by modulating inflammatory processes, oxidative stress, apoptosis and semaphorin-plexin pathway.

MAIN METHODS

The rats were divided into five groups, with eight animals per group: Sham, I/R, I/R + DMSO (1%, i.p.), I/R + Curcumin (100 mg/kg, i.p.), I/R + LOXblock-1 (2 μg/kg, i.p.).

KEY FINDINGS

The renal function biomarkers (BUN, CREA and UA) in serum were significantly increased in the I/R group. The inflammatory (TNF-α, IL-6 and MCP-1), apoptotic (CYCS and CASP3) and oxidative stress parameters (MDA, MPO, TAS and TOS) measured by ELISA were significantly increased in the I/R group. In histopathological analysis, it was observed that I/R caused serious damage to kidney tissue. SEMA3A was found to increase both serum level and mRNA expression in I/R group. It was observed that curcumin and LOXblock-1 reduce inflammatory processes, oxidative stress and apoptosis via the semaphorin-plexin pathway by both measurements and histopathological analysis. Curcumin was proved more effective than LOXblock-1 with its antioxidant feature in I/R injury.

SIGNIFICANCE

The current study reveals the protective effects of Curcumin and LOXblock-1 on acute kidney injury by suppressing SEMA3A as a new biomarker.

Dexmedetomidine Enhances Autophagy via α2-AR/AMPK/mTOR Pathway to Inhibit the Activation of NLRP3 Inflammasome and Subsequently Alleviates Lipopolysaccharide-Induced Acute Kidney Injury

Background

Acute kidney injury (AKI) is a severe complication of sepsis; however, no effective drugs have been found. Activation of the nucleotide-binding domain-like receptor protein 3 (NLRP3) inflammasome is a major pathogenic mechanism of AKI induced by lipopolysaccharide (LPS). Autophagy, a process of intracellular degradation related to renal homeostasis, effectively restricts inflammatory responses. Herein, we explored the potential protective mechanisms of dexmedetomidine (DEX), which has confirmed anti-inflammatory effects, on LPS-induced AKI.

Methods

AKI was induced in rats by injecting 10 mg/kg of LPS intraperitoneally (i.p.). Wistar rats received intraperitoneal injections of DEX (30 µg/kg) 30 min before an intraperitoneal injection of LPS. Atipamezole (ATI) (250 µg/kg) and 3-methyladenine (3-MA) (15 mg/kg) were intraperitoneally injected 30 min before the DEX injection.

Results

DEX significantly attenuated renal injury. Furthermore, DEX decreased activation of the NLRP3 inflammasome and expression of interleukins 1β and 18. In addition, autophagy-related protein and gene analysis indicated that DEX could significantly enhance autophagy. Finally, we verified the pharmacological effects of DEX on the 5′-adenosine monophosphate-activated protein kinase (AMPK)/mechanistic target of rapamycin (mTOR) pathway. Atip and 3-MA significantly reversed the protective effects of DEX.

Conclusions

Our results suggest that the protective effects of DEX were mediated by enhanced autophagy via the α₂-adrenoreceptor/AMPK/mTOR pathway, which decreased activation of the NLRP3 inflammasome. Above all, we verified the renal protective effects of DEX and offer a new treatment strategy for AKI.

Dexmedetomidine Ameliorates Lung Injury Induced by Intestinal Ischemia/Reperfusion by Upregulating Cannabinoid Receptor 2, Followed by the Activation of the Phosphatidylinositol 3-Kinase/Akt Pathway

Intestinal ischemia/reperfusion (I/R) is a clinical emergency, which often causes lung injury with high morbidity and mortality. Although dexmedetomidine has been identified to have a protective effect on lung injury caused by intestinal I/R, its specific mechanism is still elucidated. In recent years, the cannabinoid (CB₂) receptor pathway has been found to be involved in I/R injury of some organs. In the current study, we investigated whether the CB₂ receptor pathway contributes to the protective effect of dexmedetomidine on the intestinal I/R-induced lung injury in rats. Dexmedetomidine treatment upregulated the expression of CB₂ receptor and suppressed the I/R-induced increases in lung injury scores, inflammatory cell infiltration, lung wet/dry ratio, MPO activity, MDA level, inflammatory cytokines, and caspase-3 expression while augmenting SOD activity and Bcl-2 expression, indicating attenuation of lung injury. Dexmedetomidine treatment also increased the expression of Akt. The protective effects of dexmedetomidine treatment were reversed by the CB₂ receptor antagonist AM630 or the PI3K inhibitor wortmannin. And the CB₂ receptor antagonist AM630 also downregulated the expression of Akt. Thus, our findings suggest that treatment with dexmedetomidine provides a protective role against lung injury caused by intestinal I/R in rats, possibly due to the upregulation of the CB₂ receptor, followed by the activation of the PI3K/Akt pathway.

Perioperative Dexmedetomidine Improves Outcomes of Kidney Transplant

Graft function is crucial for successful kidney transplantation. Many factors may affect graft function or cause delayed graft function (DGF), which decreases the prognosis for graft survival. This study was designed to evaluate whether the perioperative use of dexmedetomidine (Dex) could improve the incidence of function of graft kidney and complications after kidney transplantation. A total of 780 patients underwent kidney transplantations, 315 received intravenous Dex infusion during surgery, and 465 did not. Data were adjusted with propensity scores and multivariate logistic regression was used. The primary outcomes are major adverse complications, including DGF and acute rejection in the early post‐transplantation phase. The secondary outcomes included length of hospital stay (LOS), infection, overall complication, graft functional status, post‐transplantation serum creatinine values, and estimated glomerular filtration rate (eGFR). Dex use significantly decreased DGF (19.37% vs. 23.66%; adjusted odds ratio, 0.744; 95% confidence interval, 0.564–0.981; P = 0.036), risk of infection, risk of acute rejection in the early post‐transplantation phase, the risk of overall complications, and LOS. However, there were no statistical differences in 90‐day graft functional status or 7‐day, 30‐day, and 90‐day eGFR. Perioperative Dex use reduced incidence of DGF, risk of infection, risk of acute rejection, overall complications, and LOS in patients who underwent kidney transplantation.

Organ-Protective Effects and the Underlying Mechanism of Dexmedetomidine

Dexmedetomidine (DEX) is a highly selective α2 adrenergic receptor (α2AR) agonist currently used in clinical settings. Because DEX has dose-dependent advantages of sedation, analgesia, antianxiety, inhibition of sympathetic nervous system activity, cardiovascular stabilization, and significant reduction of postoperative delirium and agitation, but does not produce respiratory depression and agitation, it is widely used in clinical anesthesia and ICU departments. In recent years, much clinical study and basic research has confirmed that DEX has a protective effect on a variety of organs, including the nervous system, heart, lungs, kidneys, liver, and small intestine. It acts by reducing the inflammatory response in these organs, activating antiapoptotic signaling pathways which protect cells from damage. Therefore, based on wide clinical application and safety, DEX may become a promising clinical multiorgan protection drug in the future. In this article, we review the physiological effects related to organ protection in α2AR agonists along with the organ-protective effects and mechanisms of DEX to understand their combined application value.

Dexmedetomidine Preconditioning Protects Rats from Renal Ischemia-Reperfusion Injury Accompanied with Biphasic Changes of Nuclear Factor-Kappa B Signaling

Acute kidney injury (AKI) is one of the most common and troublesome perioperative complications. Dexmedetomidine (DEX) is a potent α2-adrenoceptor (α2-AR) agonist with anti-inflammatory and renoprotective effects. In this study, a rat renal ischemia–reperfusion injury (IRI) model was induced. At 24 h after reperfusion, the IRI-induced damage and the renoprotection of DEX preconditioning were confirmed both biochemically and histologically. Changes in nuclear factor-kappa B (NF-κB), as well as its downstream anti-inflammatory factor A20 and proinflammatory factor tumor necrosis factor-α (TNF-α), were detected. Atipamezole, a nonselective antagonist, was then added 5 min before the administration of DEX to further analyze DEX's effects on NF-κB, and another anti-inflammatory medicine, methylprednisolone, was used in comparison with DEX, to further analyze DEX's effects on NF-κB. Different concentrations of DEX (0 nM, 0.1 nM, 1 nM, 10 nM, 100 nM, 1 μM, and 10 μM) were applied to preincubated human renal tubular epithelial cell line (HK-2) cells in vitro. After anoxia and reoxygenation, the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) tetrazolium assay and enzyme-linked immunosorbent assay (ELISA) were performed to evaluate the levels of NF-κB downstream anti-inflammatory cytokines. The results showed that, unlike methylprednisolone, DEX preconditioning led to a time-dependent biphasic change (first activation then inhibition) of NF-κB in the rat renal IRI models that were given 25 μg/kg i.p. It was accompanied by a similarly biphasic change of TNF-α and an early and persistent upregulation of A20. In vitro, DEX's cellular protection showed a concentration-dependent biphasic change which was protective within the range of 0 to 100 nM but became opposite when concentrations are greater than 1 μM. The changes in the A20 and NF-κB messenger RNA (mRNA) levels were consistent with the renoprotective ability of DEX. In other words, DEX preconditioning protected the rats from renal IRI via regulation biphasic change of NF-κB signaling.

The JAK2/STAT3 pathway is involved in dexmedetomidine-induced myocardial protection in rats undergoing cardiopulmonary bypass

Background

Many studies have reported that dexmedetomidine protects organs from ischemia/reperfusion-induced injury. However, the mechanism of this protective effect remains inconclusive.

Methods

Rats were randomly divided into 6 groups (n=8). Rats in the sham group were not subjected to cardiopulmonary bypass (CPB) while rats in the other groups underwent CPB for 2 h. Groups L and H received a low and a high dose of dexmedetomidine, respectively. Rats in group AG490 received 10 mg/kg of the Janus kinase 2 (JAK2) inhibitor, AG490, 30 min before anesthesia. Plasma levels of the inflammatory cytokines, interleukin (IL)-6 and IL-10, were measured by enzyme-linked immunosorbent (ELISA), and the apoptosis rate of myocardial cells, the expression of JAK2 and signal transducer and activator of transcription (STAT)3 mRNA, and the protein expression of JAK2, STAT3, pJAK2, pSTAT3, and caspase-3 were analyzed in myocardial tissues by real-time quantitative polymerase chain reaction (qRT-PCR), western blotting, and immunohistochemistry.

Results

We observed that, in both group L and group H, the level of IL-6 decreased (P<0.05), and the apoptosis rate of myocardial cells were reduced (P<0.05) compared to those in the CPB group. Moreover, qRT-PCR results revealed that dexmedetomidine administration reduced the expression of JAK2 and STAT3 mRNA (P<0.05); pJAK2 and pSTAT3 (P<0.05) protein levels were also reduced as assessed by western blotting and immunohistochemistry (P<0.05).

Conclusions

Dexmedetomidine treatment reduced CPB-related myocardial injury by inhibiting inflammatory reactions and myocardial apoptosis, and can be a potential therapy in CPB-related surgery.

Role of JNK Signaling Pathway in Dexmedetomidine Post-Conditioning-Induced Reduction of the Inflammatory Response and Autophagy Effect of Focal Cerebral Ischemia Reperfusion Injury in Rats

To investigate the effect of dexmedetomidine post-conditioning on the inflammatory response and autophagy effect of focal cerebral ischemia reperfusion injury in rats, and further to study its potential mechanisms. Water maze was conducted to evaluate spatial learning and memory ability of middle cerebral artery occlusion (MCAO) rats. TTC staining was used to observe the area of cerebral infarction. The expressions of inflammatory factors in serum were detected by ELISA. TUNEL assay, HE staining, and transmission electron microscopy were used to detect the apoptosis of neurons, neuro-cytopathic changes, and the formation of auto-phagosome in hippocampus CA1 region, respectively. The mRNA and protein expression of Beclin-1, Caspase-3, and light chain 3 (LC3) were detected by qRT-PCR and Western blot. Moreover, the activity of C-Jun N-terminal kinase (JNK) pathway was detected by Western blot. The escape latency (EL); cerebral infarction area ratio; positive apoptosis; neuron pathological changes; auto-phagosome numbers; inflammatory factor contents; mRNA and protein expressions of Beclin-1, Caspase-3 and LC3II/I; and the phosphorylation level of JNK were decreased, while the times across platform and the times stayed in the quadrant of the original platform were increased after dexmedetomidine treatment. However, the protective effect of dexmedetomidine on brain injury in MCAO rats was reversed by JNK pathway activator. Dexmedetomidine post-conditioning could improve learning and memory dysfunction caused by MCAO in rats and reduce the inflammatory response and autophagy effect. The mechanism may be related to inhibition of JNK pathway activation.

Longxuetongluo capsule alleviates lipopolysaccharide-induced neuroinflammation by regulating multiple signaling pathways in BV2 microglia cells

BACKGROUND

Longxuetongluo capsule (LTC), derived from the total phenolic compounds of Chinese dragon's blood, is now used in the treatment of ischemic stroke in convalescence. The aim of this study is to explore the neuroprotective effect of LTC from the perspective of neuroinflammation.

METHODS

Cell viability and lactate dehydrogenase (LDH) release were measured by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) and LDH assay kit. Proinflammatory mediators and cytokines production including Nitric Oxide (NO), prostaglandin E2, (PGE2), interleukin (IL-β), IL-6, and tumor necrosis factor-α (TNF-α) were detected by enzyme-linked immunosorbent assay (ELISA) assay. In addition, western blot was used to detect the expression of inflammatory proteins associated with the mitogen-activated protein kinases (MAPKs), janus kinase/signal transducer and activator of tranions (JAK/STAT), nuclear transcription factor κB (NF-κB), and nuclear factor erythroid-2-related actor 2/heme oxygenase 1 (Nrf2/HO-1) signaling pathways. Moreover, immunofluorescence assay and electrophoretic mobility shift assays (EMSA) were performed to determine the Nrf2 translocation and the binding-DNA activity of NF-κB, respectively.

RESULTS

LTC at 0.5 to 2 μg/mL significantly increased cell viability and decreased LDH, NO, PGE2, IL-1β, IL-6, and TNF-α production in oxygen-glucose deprivation/reoxygenation (OGD/R) and lipopolysaccharide (LPS)-induced BV2 microglia cells. Meanwhile, LTC not only decreased the protein expressions of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) but also down-regulated phosphorylation of extracellular signal-regulated kinase (ERK)1/2, p38, and up-regulated HO-1 expression via nuclear translocation of Nrf2. LTC can significantly inhibit the phosphorylation of JAK1/STAT3 and reduce the translocation of NF-κB from cytosol to nucleus as well as the binding-DNA activity. PC12 cell pretreated with LTC-condition medium (CM) significantly alleviated LPS-induced neurotoxicity and increased PC12 cell viability in a dose-dependent manner.

CONCLUSION

The present study showed that LTC exhibited a strong antineuroinflammatory activity and neuroprotective effects on LPS-stimulated BV2 microglial cells and PC12 cells.

Dexmedetomidine Protects SK-N-SH Nerve Cells from Oxidative Injury by Maintaining Iron Homeostasis

Ferroptosis is characterized by the accumulation of iron-derived reactive oxygen species (ROS). Ferroptosis causes neuronal death in multiple neurological disorders. Dexmedetomidine (Dex), an extensively used anesthetic, has neuroprotective effects against ROS, but its effect on iron metabolism remains unknown. In this study, SK-N-SH cells were treated with Dex for 24 h before treatment with 100 µM tert-butyl hydroperoxide (t-BHP; an ROS inducer) for 1 h. Afterward, intracellular ROS and labile ferrous iron [Fe(II)] levels were assessed. Dex hindered the increase in cellular ROS and labile Fe(II) levels caused by t-BHP, although Dex alone had no effect on labile Fe(II) level. t-BHP increased the expression of iron importers, transferrin receptor-1 and divalent metal transporter-1, and iron regulatory protein 1 and 2. These effects were abrogated by Dex treatment and SP-1 knockdown. t-BHP increased the phosphorylation of c-Jun N-terminal kinase (JNK) and signal transducer and activator of transcription 4 (STAT4), the primary up-stream activators of SP-1, but Dex decreased this. This study, for the first time, revealed that the antioxidative effect of Dex is partly associated to the inhibition of intracellular iron accumulation induced by t-BHP. Dex regulates iron metabolism by regulating iron importers and exporters through JNK/Sp1 and Stat4/Sp1 signaling. It is worth investigating whether Dex can protect neurons from ferroptosis.