Down-regulated expression of AQP5 on lung in rat DIC model induced by LPS and its effect on the development of pulmonary edema

Emergency Hysterectomy Following Placental Abruption in a Patient With a History of Substance Abuse: A Case Report

Placental abruption is a serious medical condition that can occur during pregnancy, involving the premature separation of the placenta from the inner uterine wall before childbirth. This detachment often leads to severe bleeding, and if conventional methods prove ineffective in managing the bleeding, a hysterectomy may be deemed necessary to ensure the mother's safety. This case report details the management of a 22-year-old female, gravida IV, para III, who experienced placental abruption during her fourth pregnancy. An emergent cesarean section resulted in severe postpartum hemorrhage and disseminated intravascular coagulation (DIC). Positive drug tests for cocaine and methamphetamines added further complexity, leading to an unplanned hysterectomy for life-saving measures. This case underscores the critical importance of early recognition, multidisciplinary collaboration, and timely intervention in managing obstetric emergencies within the context of substance abuse.

Perillaldehyde ameliorates lipopolysaccharide-induced acute lung injury via suppressing the cGAS/STING signaling pathway

Acute lung injury (ALI) is a common life-threatening illness characterized by a lung inflammatory response and oxidative stress, and effective agent therapies are currently lacking. mtDNA can be recognized by cGAS/STING, the dysregulation of which leads to inflammatory diseases, such as ALI. Perillaldehyde(PAH), one of the major active components of traditional Chinese medicine made from Perilla frutescens, has antioxidant and antiinflammatory effects. The aim of this study was to explore whether PAH can protect against lipopolysaccharide (LPS)-induced ALI and whether its protective effect is exerted through the regulation of cGAS/STING signaling. We found that PAH significantly inhibited lung histological changes, inflammatory cell infiltration, and the overproduction of inflammatory cytokines induced by LPS. Moreover, PAH inhibited LPS-induced oxidative stress, as shown by the deceases in superoxide dismutase (SOD) and glutathione(GSH) levels and increased in malondialdehyde (MDA) and lactate dehydrogenase (LDH) levels. In addition, PAH markedly downregulated the expression of cGAS, STING, p-TBK, p-IRF3, p-P65, and p-IκB, and pharmacological inhibition of cGAS/STING inhibited ALI- induced by LPS. Furthermore, the levels of mitochondrial ROS (mROS) and mtDNA were increased, and cGAS/STING-mediated IRF3/NF-κB signaling was activated during the inflammatory response- induced by LPS in RAW264.7 cells. In addition, pretreatment with the STING activator partially abolished the inhibitory effect of PAH on the inflammation and activation of STING-mediated IRF3/NF-κB signaling induced by LPS. Overall, the results revealed that PAH can effectively alleviate ALI by inhibiting cGAS/STING-mediated IRF3/NF-κB signaling, and that PAH may be a potential candidate agent for the treatment of ALI.

Molecular and Physiological Functions of PACAP in Sweat Secretion

Sweat plays a critical role in human body, including thermoregulation and the maintenance of the skin environment and health. Hyperhidrosis and anhidrosis are caused by abnormalities in sweat secretion, resulting in severe skin conditions (pruritus and erythema). Bioactive peptide and pituitary adenylate cyclase-activating polypeptide (PACAP) was isolated and identified to activate adenylate cyclase in pituitary cells. Recently, it was reported that PACAP increases sweat secretion via PAC1R in mice and promotes the translocation of AQP5 to the cell membrane through increasing intracellular [Ca²⁺] via PAC1R in NCL-SG3 cells. However, intracellular signaling mechanisms by PACAP are poorly clarified. Here, we used PAC1R knockout (KO) mice and wild-type (WT) mice to observe changes in AQP5 localization and gene expression in sweat glands by PACAP treatment. Immunohistochemistry revealed that PACAP promoted the translocation of AQP5 to the lumen side in the eccrine gland via PAC1R. Furthermore, PACAP up-regulated the expression of genes (Ptgs2, Kcnn2, Cacna1s) involved in sweat secretion in WT mice. Moreover, PACAP treatment was found to down-regulate the Chrna1 gene expression in PAC1R KO mice. These genes were found to be involved in multiple pathways related to sweating. Our data provide a solid basis for future research initiatives in order to develop new therapies to treat sweating disorders.

Soy isoflavone reduces LPS-induced acute lung injury via increasing aquaporin 1 and aquaporin 5 in rats

Acute lung injury (ALI) followed with severe inflammation and oxidative stress. Anti-inflammatory and antioxidant are the properties of aquaporin 1 (AQP1) and aquaporin 5 (AQP5). The goal of this study was to see if soy isoflavone can diminish lipopolysaccharide (LPS)-induced ALI and the underling mechanism. LPS-induced ALI was given to Sprague-Dawley rats 14 days following oophorectomy. One hour before the LPS challenge, estradiol (1 mg/kg) was administered subcutaneously as positive control and soy isoflavone was intragastric administration for 14 days prior to LPS challenge with different doses. Six hours after LPS challenge, the pulmonary edema, pathophysiology, inflammation, and the oxidative stress in lung tissues of rats were discovered. We found that soy isoflavone can reduce pulmonary edema and the lung pathology in a dose-dependent manner. Furthermore, tumor necrosis factor-alpha, interleukin-1β, and interleukin-6 were decreased in rats treated with soy isoflavone. Meanwhile, soy isoflavone reduced pulmonary oxidative stress by decreasing malondialdehyde levels, while increasing superoxide dismutase levels in lung tissues in a dose-dependent manner. Mechanically, we found that the mRNA and protein level of AQP1 and AOP5 were increased in lung tissues of rats treated with soy isoflavone compared the LPS-treated rats. Thus, soy isoflavone alleviates LPS-induced ALI through inducing AQP1 and AQP5.

Aquaporin-5 Dynamic Regulation

Aquaporin-5 (AQP5), belonging to the aquaporins (AQPs) family of transmembrane water channels, facilitates osmotically driven water flux across biological membranes and the movement of hydrogen peroxide and CO₂. Various mechanisms have been shown to dynamically regulate AQP5 expression, trafficking, and function. Besides fulfilling its primary water permeability function, AQP5 has been shown to regulate downstream effectors playing roles in various cellular processes. This review provides a comprehensive overview of the current knowledge of the upstream and downstream effectors of AQP5 to gain an in-depth understanding of the physiological and pathophysiological processes involving AQP5.

Ultramicronized Palmitoylethanolamide in the Management of Sepsis-Induced Coagulopathy and Disseminated Intravascular Coagulation

Disseminated intravascular coagulation (DIC) is a severe condition characterized by the systemic formation of microthrombi complicated with bleeding tendency and organ dysfunction. In the last years, it represents one of the most frequent consequences of coronavirus disease 2019 (COVID-19). The pathogenesis of DIC is complex, with cross-talk between the coagulant and inflammatory pathways. The objective of this study is to investigate the anti-inflammatory action of ultramicronized palmitoylethanolamide (um-PEA) in a lipopolysaccharide (LPS)-induced DIC model in rats. Experimental DIC was induced by continual infusion of LPS (30 mg/kg) for 4 h through the tail vein. Um-PEA (30 mg/kg) was given orally 30 min before and 1 h after the start of intravenous infusion of LPS. Results showed that um-PEA reduced alteration of coagulation markers, as well as proinflammatory cytokine release in plasma and lung samples, induced by LPS infusion. Furthermore, um-PEA also has the effect of preventing the formation of fibrin deposition and lung damage. Moreover, um-PEA was able to reduce the number of mast cells (MCs) and the release of its serine proteases, which are also necessary for SARS-CoV-2 infection. These results suggest that um-PEA could be considered as a potential therapeutic approach in the management of DIC and in clinical implications associated to coagulopathy and lung dysfunction, such as COVID-19.

Estradiol attenuates LPS-induced acute lung injury via induction of aquaporins AQP1 and AQP5

Background

Acute lung injury (ALI) is associated with increased inflammation and oxidative stress. Estradiol is produced by the ovaries and is the most active hormone of estrogen. Our aim was to investigate whether estradiol contributes to protect against lipopolysaccharide (LPS)-induced ALI via induction of aquaporins AQP1 and AQP5 and the underlying mechanisms. Methods and results For induction of ALI, LPS was applied once by intraperitoneal injection in SD rats 14 days after oophorectomy. To assess the therapeutic effects of estradiol on LPS-induced ALI, estradiol was subcutaneously injected for 1 h prior to LPS challenge. Estradiol can significantly attenuate the lung edema reflected by decreasing wet-to-dry weight ratio and permeability of lung and total protein concentration of bronchial lavage fluid (BALF). Results of histological detection showed that estradiol attenuated the lung injury reflected by reducing edema, congestion, and thickening pulmonary septal of lung tissues. In addition, estradiol attenuated TNF-α, IL-1β, and IL-6 and oxidative stress in lung tissues. Estradiol was more effective than estradiol associated with ERα antagonist or ERβ antagonist in protecting against LPS-induced ALI in rats. Mechanistically, we investigate whether estradiol regulates the expression of AQP1 and AQP5 in lung tissues. Of interest, estradiol upregulates AQP1 and AQP5 mRNA and protein expression. Taken together, these results demonstrate that estradiol can increase the expression of AQP1 and AQP5, which plays a critical role in ameliorating oxidative stress and downregulating inflammatory responses induced by LPS.Conclusion Therefore, these findings strongly suggest that AQP1 and AQP5 mediate the anti-inflammatory and antioxidant effects of estradiol.

Dexmedetomidine protects against endothelial injury in septic rats induced by cecal ligation and puncture by decreasing angiopoietin 2 and increasing vascular endothelial cadherin levels

The aim of the present study was to investigate the protective effect of dexmedetomidine (Dex) on endothelial injury in a cecal ligation and puncture (CLP)-induced rat model of sepsis. A total of 36 male Sprague-Dawley rats were divided into three groups: Sham, CLP and CLP + Dex. The wet/dry (W/D) ratio of lung weight, hematoxylin and eosin (H&E) staining of lung tissue, plasma levels of angiopoietin (Ang)1 and 2, ratio of Ang2/1 and vascular endothelial (VE)-cadherin protein expression levels in lung tissue were determined. The W/D ratio of lung tissue in the CLP + Dex group was significantly lower than that in the CLP group (P<0.01). The H&E staining results indicated that Dex treatment reduced the levels of CLP-induced alveolar septum widening, infiltrating white blood cells and congestion, when compared with CLP alone. In addition, the expression levels of plasma Ang2 and the Ang2/1 ratio in the CLP + Dex group were significantly lower than those of the CLP rats (P<0.01). Furthermore, the level of VE-cadherin protein in lung tissue of the CLP + Dex group was higher than that of the CLP group (P<0.05). The results indicated that Dex had a protective effect against CLP-induced endothelial injury, through the ability to reduce expression of the endothelial injury factor Ang2 and increase the expression of the endothelial adhesion junction factor VE-cadherin in a septic rat model. These data suggest a potential application of Dex in the clinical treatment of sepsis.

Aquaporins in lung health and disease: Emerging roles, regulation, and clinical implications

Aquaporins (AQPs) aka water channels are a family of conserved transmembrane proteins (~30 kDa monomers) expressed in various organ systems. Of the 13 AQPs (AQP0 through AQP12) in the human body, four (AQPs 1, 3, 4, and 5) are expressed in the respiratory system. These channels are conventionally known for mediating transcellular fluid movements. Certain AQPs (aquaglyceroporins) have the capability to transport glycerol and potentially other solutes. There is an emerging body of literature unveiling the non-conventional roles of AQPs such as in cell proliferation and migration, gas permeation, signal potentiation, etc. Initial gene knock-out studies established a physiological role for lung AQPs, particularly AQP5, in maintaining homeostasis, by mediating fluid secretion from submucosal glands onto the airway surface liquid (ASL) lining. Subsequent studies have highlighted the functional significance of AQPs, particularly AQP1 and AQP5 in lung pathophysiology and diseases, including but not limited to chronic and acute lung injury, chronic obstructive pulmonary disease (COPD), other inflammatory lung conditions, and lung cancer. AQP1 has been suggested as a potential prognostic marker for malignant mesothelioma. Recent efforts are directed toward exploiting AQPs as targets for diagnosis, prevention, intervention, and/or treatment of various lung conditions. Emerging information on regulatory pathways and directed mechanistic research are posited to unravel novel strategies for these clinical implications. Future considerations should focus on development of AQP inhibitors, blockers, and modulators for therapeutic needs, and better understanding the role of lung-specific AQPs in inter-individual susceptibility to chronic lung diseases such as COPD and cancer.

AGK2 ameliorates mast cell-mediated allergic airway inflammation and fibrosis by inhibiting FcεRI/TGF-β signaling pathway

Asthma is characterized by airway hyperresponsiveness and allergic inflammation, detrimentally affecting the patients' quality of life. The development of new drugs for the treatment of asthma is warranted to alleviate these issues. Recent studies have demonstrated that sirtuin2 (SIRT2) aggravates asthmatic inflammation by up-regulation of T-helper type 2 responses and macrophage polarization. However, effects of SIRT2 on mast cell activation remain obscure. In this study, we investigated the effects of AGK2, an inhibitor for SIRT2, on mast cell-mediated allergic airway inflammation. Pre-treatment with AGK2 inhibited degranulation of mast cells by suppressing the FcεRI signaling pathway and intracellular calcium influx. The expression of pro-inflammatory cytokines, such as tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-4, IL-5, IL-6, and IL-8, was inhibited via regulation of transcription factors such as NF-κB and NRF2. These effects of AGK2 were verified in passive cutaneous anaphylaxis and acute lung injury animal models. AGK2 attenuated Evans blue pigmentation by inhibiting mast cell activation and lung barrier dysfunction by inhibiting inflammatory responses in these animal models. In the ovalbumin (OVA)-induced allergic airway inflammation murine model, AGK2 alleviated allergic asthma symptoms such as lung histological changes (immune cell and mast cell infiltration, collagen deposition, and α-smooth muscle actin expression) and serum immunoglobulins (Ig) levels (IgE, OVA-specific IgE, IgG1, and IgG2a). Moreover, AGK2 reduced the levels of pro-inflammatory cytokines (TNF-α, IL-1β, IL-4, IL-5, and IL-6) and inflammatory mediators (myeloperoxidase, eosinophil peroxidase, and tumor growth factor-α) in the bronchoalveolar lavage fluid and lung tissues. In addition, the anti-fibrotic effects of AGK2 were verified using lung epithelial cells and TGF-β/Smad reporter stable cells. In conclusion, our findings suggest that SIRT2 plays a role in mast cell-mediated airway inflammatory disease. Therefore, AGK2 is a good potential candidate for treating allergic asthma and lung inflammation.

Aquaporin 1 alleviates acute kidney injury via PI3K-mediated macrophage M2 polarization

BACKGROUND

Lipopolysaccharide (LPS)-induced acute kidney injury (AKI) is associated with an abnormal immune response. Accumulating evidence has demonstrated that aquaporin 1 (AQP1) prevents kidney tissue injury in LPS-induced AKI by mediating immune response. However, the underlying mechanisms remain obscure. Macrophages as immune cells with multiple phenotypes are important mediators in tissue homeostasis and host defense. We propose that macrophage polarization is implicated in AQP1-mediated immune response.

METHODS

Herein we established sepsis-induced AKI model rats through intraperitoneal injection of LPS into Wistar rats to reveal immune mechanism of damage. We also used LPS-induced mouse RAW264.7 cells to elucidate the molecular mechanism of macropage polarization.

RESULTS

Histopathology showed that renal tubular epithelial cells in the model group were swollen, inflammatory exudation was obvious and the inflammatory factors, interleukin-6 (IL-6) and tumor necrosis factor α (TNF-α) were increased. Western blotting showed PI3K was upregulated in the model group. Serum creatinine and urea nitrogen increased after LPS injection. Renal AQP1 mRNA is downregulated and serum AQP1 protein increased first and then decreased in LPS-induced AKI rats. M2 macrophage markers (Arg-1, CD206) were increased in repair stage. In addition, treatment of murine macrophages (RAW264.7) with AQP1 siRNA resulted in decreased PI3K activation and M2 polarization, but increased IL-6 and TNF-α. Moreover, inhibiting PI3K with wortmannin imitated the results of AQP1 silencing.

CONCLUSIONS

Macrophage M2 polarization is likely the cellular mechanism underlying the anti-AKI property of AQP1, and PI3K activation is involved in the AQP1-induced M2 phenotype switch.

Aquaporins in the lung

The lung is the interface between air and blood where the exchange of oxygen and carbon dioxide occurs. The surface liquid that is directly exposed to the gaseous compartment covers both conducting airways and respiratory zone and forms the air-liquid interface. The barrier that separates this lining fluid of the airways and alveoli from the extracellular compartment is the pulmonary epithelium. The volume of the lining fluid must be kept in a range that guarantees an appropriate gas exchange and other functions, such as mucociliary clearance. It is generally accepted that this is maintained by balancing resorptive and secretory fluid transport across the pulmonary epithelium. Whereas osmosis is considered as the exclusive principle of fluid transport in the airways, filtration may contribute to alveolar fluid accumulation under pathologic conditions. Aquaporins (AQP) facilitate water flux across cell membranes, and as such, they provide a transcellular route for water transport across epithelia. However, their contribution to near-isosmolar fluid conditions in the lung still remains elusive. Herein, we discuss the role of AQPs in the lung with regard to fluid homeostasis across the respiratory epithelium.

Cytoprotective effect of aquaporin 1 against lipopolysaccharide-induced apoptosis and inflammation of renal epithelial HK-2 cells

Sepsis is the most common underlying disease of disseminated intravascular coagulation. Acute kidney injury is a common and serious complications of sepsis. In the present study, a lipopolysaccharide (LPS)-induced human proximal tubule cell line (HK-2 cells) was selected as an in vitro model of septic acute kidney injury. The aim of the present study was to investigate whether aquaporin 1 (AQP-1) has a cytoprotective role in LPS-induced HK-2 cells. HK-2 cells were treated with 0-16 µg/ml LPS for 0-24 h to establish the in vitro model of sepsis. The results demonstrated that AQP-1 levels were the lowest of the eight AQP genes expressed in LPS-induced HK-2 cells. Prior to LPS treatment, HK-2 cells were transfected with pcDNA-AQP-1 or small interfering-AQP-1 and cell counting kint-8 and flow cytometry assays were performed to assess cell viability and apoptosis rate, respectively. Changes in the expression of proinflammatory cytokines and chemokines, as well as important factors in the p38, extracellular signal-regulated kinase (ERK)1/2 and c-Jun N-terminal kinase (JNK) pathways, were assessed using reverse transcription-quantitative polymerase chain reaction, western blotting and ELISA, respectively. LPS treatment reduced viability, increased apoptosis and upregulated the expression of proinflammatory cytokines and chemokines in HK-2 cells. AQP-1 overexpression significantly reversed the effects of LPS and downregulated the expression of tumor necrosis factor-α, interleukin (IL)-8, IL-1β and monocyte chemoattractant protein-1. The p38, ERK1/2 and JNK pathways were activated by LPS; however, the p38 and ERK1/2 pathways were blocked in AQP-1-overexpressing cells. AQP-1 overexpression was demonstrated to confer a survival advantage to LPS-injured HK-2 cells by controlling cell viability, apoptosis and inflammation, possibly via modulation of the p38 and ERK1/2 pathways. The results of the present study suggest that AQP-1 may be an effective treatment for acute kidney injury caused by sepsis.

[Risk factors for neonatal pulmonary hemorrhage in the neonatal intensive care unit of a municipal hospital]

OBJECTIVE

To investigate the risk factors for neonatal pulmonary hemorrhage (NPH) in the neonatal intensive care unit (NICU) of a municipal hospital, and to provide a basis for the early identification and treatment of NPH.

METHODS

A total of 112 neonates who were admitted to the NICU of Shaoyang Central Hospital of Hunan Province and diagnosed with NPH were enrolled as the case group. A nested case-control method was used to select, as a control group (n=224), the neonates who underwent the treatment with an assisted mechanical ventilator and did not experience pulmonary hemorrhage. Univariate analysis and unconditional logistic regression analysis were used to identify the high risk factors for NPH.

RESULTS

The univariate analysis showed that compared with the control group, the case group had significantly higher incidence rates of gestational diabetes and cholestasis in mothers, cesarean delivery, gestational age <34 weeks, 5-minute Apgar score ≤5, birth weight <2 500 g, heart failure and disseminated intravascular coagulation (DIC) before the development of NPH, partial pressure of oxygen/fraction of inspired oxygen (oxygenation index, OI) ≤100, and a reduction in mean platelet volume. The multivariate logistic regression analysis showed that DIC, heart failure, and OI ≤100 were independent risk factors for NPH (OR=33.975, 3.975, 1.818 respectively; P<0.05).

CONCLUSIONS

Heart failure, OI ≤100, and DIC are risk factors for the development of NPH in the NICU of the municipal hospital.

Involvement of water channel Aquaporin 5 in H2S-induced pulmonary edema

Acute exposure to hydrogen sulfide (H₂S) poses a significant threat to life, and the lung is one of the primary target organs of H₂S. However, the mechanisms involved in H₂S-induced acute pulmonary edema are poorly understood. This study aims to investigate the effects of H₂S on the expression of water channel aquaporin 5 (AQP5) and to elucidate the signaling pathways involved in AQP5 regulation. In an in vivo study, C57BL6 mice were exposed to sub-lethal concentrations of inhaled H₂S, and histological injury of the lungs and ultrastructure injury of the epithelial cells were evaluated. With real-time PCR and western blot assays, we found that H₂S exposure contributed to a significant decrease in AQP5 expression both in murine lung tissue and the A549 cell line, and the ERK1/2 and p38 MAPK signaling pathways were demonstrated to be implicated in AQP5 regulation. Therefore, adjusting AQP5 protein levels could be considered a therapeutic strategy for the treatment of APE induced by H₂S and other hazardous gases.

Mosla scabra flavonoids ameliorate the influenza A virus-induced lung injury and water transport abnormality via the inhibition of PRR and AQP signaling pathways in mice

ETHNOPHARMACROLOGICAL RELEVANCE

Mosla scabra (Thunb.) C.Y. Wu and H.W. Li has been used as a traditional medicinal herb for centuries in East Asian countries. It has antibacterial, antiviral, antioxidant, anti-inflammatory and immunomodulatory effects. In folk medicine, it is used as a remedy for the treatment of pulmonary diseases, such as fever, cold, cough, pulmonary edema and emphysema.

AIM OF THE STUDY

This study was to investigate the protective mechanism of total flavonoids from M. scabra (MF) in influenza A virus (IAV)-infected mice.

MATERIALS AND METHODS

The mice were infected with IAV and then were treated daily with MF for five days. At the end of the experiment, the levels of inflammatory-related cytokines (IFN-α, IL-6, TNF-α and IL-1β) were determined by ELISA. Pathological changes of lung tissue were examined by H&E staining. The protein expressions of AQP5, p-p38, caspase-3 and NF-κB p65 were detected by western blot analysis while the gene expressions of key effectors in AQP5 and PRRs signaling pathways were detected by real-time Fluorescence Quantitative Polymerase Chain Reaction (RFQ-PCR) analysis.

RESULTS

The results showed that treatment with MF at doses of 120-360mg/kg for five days to IAV-infected mice significantly attenuated IAV-induced pulmonary injury and decreased the serum levels of IL-6, TNF-α and IL-1β, but increased IFN-α levels. MF treatment could up-regulate the mRNA expressions of TLR-7, RIG-1, TRAF6, Bcl-2, Bax, VIPR1, PKCα and AQP5 and down-regulate caspase-3 and NF-κB p65 protein expression.

CONCLUSION

Treatment with MF could significantly alleviate IAV-induced pulmonary inflammation, apoptosis and water transport abnormality, which was probably through the regulation of TLR7, RIG-1 and AQP5 signaling pathway.

Effect of dobutamine on lung aquaporin 5 in endotoxine shock-induced acute lung injury rabbit

BACKGROUND

Dobutamine, a commonly used vasoactive drug, has been reported to reduce pulmonary edema and protect against acute lung injury (ALI) by up-regulating aquaporin 5 (AQP5) expressions. However, the underlying mechanism is still elusive.

METHODS

ALI was induced by intravenous injection of LPS. Seventy male New Zealand white rabbits were randomly divided into seven groups: sham group, ALI group, dobutamine low-dose group [group ALI + Dob (L)], dobutamine medium-dose group [group ALI + Dob (M)], dobutamine high-dose group [group ALI + Dob (H)], ALI + Dob (H) + ICI group and sham + ICI group. ICI 118,551, a potent and specific beta-2 antagonist, could block the effect of dobutamine. The animals were sacrificed at 3 h after endotoxic shock and lungs were removed. The arterial blood gas was analyzed. The lung wet to dry (W/D) ratio was determined. The level of cyclic AMP (cAMP) in lung tissue was assessed by ELISA. The expression of AQP5 protein was determined by western blotting and immunohistochemistry. The pathological alteration in lung tissue was evaluated by optical microscopy and electron microscope, and lung injury score was assessed.

RESULTS

Dobutamine increased AQP5 protein expression and cAMP level in a dose-dependent manner. Meanwhile, the degree of lung pathological and ultrastructural lesion was ameliorated and arterial blood gas was improved obviously. Additionally, W/D ratio and histological scores decreased significantly. However, the AQP5 protein expression and cAMP level were significantly decreased in group ALI + Dob (H) + ICI than that in group ALI + Dob (H), the degree of lung pathological and ultrastructural lesion was more serious in group ALI + Dob (H) + ICI than that in group ALI + Dob (H) and the arterial blood gas was not obviously improved.

CONCLUSIONS

These results suggested that protective effect of dobutamine against endotoxin shock-induced ALI may be due to its ability of up-regulating AQP5 protein expression via increasing intracellular cAMP concentration.

Hyperbaric oxygen therapy palliates lipopolysaccharide-induced acute lung injury in rats by upregulating AQP1 and AQP5 expression

PURPOSE

Hyperbaric oxygen (HBO) therapy has been suggested to palliate acute lung injury (ALI), but the mechanisms involved are not well understood. This study is to elucidate the involvement of AQP1 and AQP5 in the HBO related ALI therapy.

MATERIALS AND METHODS

lipopolysaccharide (LPS) was administrated into SD rats to obtain ALI models. Pressure of oxygen (PaO2) and carbon dioxide (PaCO2) in arterial blood and oxygenation index in rats after LPS and HBO treatments were determined. Pathological changes of the lungs were examined by hematoxylin and eosin staining. Alteration of TNF-α level during LPS and HBO treatments was evaluated with ELISA analysis. Western blot was employed to assess the expression of AQP1 and AQP5.

RESULTS

Blood gas indexes were largely decreased by LPS administration, which responded to HBO. Pathological examination showed that the inflammation symptoms in lungs induced by LPS were also palliated after HBO preconditioning. LPS induced the expression of TNF-α at a high level which could be downregulated by HBO and TNF-α antagonist treatments. Results of AQP1 and AQP5 determination found that HBO and TNF-α antagonist would upregulate the expression of AQP1 and AQP5 which was inhibited in rats with ALI.

CONCLUSIONS

HBO therapy palliated LPS-induced ALI in rats by downregulating TNF-α expression. HBO also upregulated AQP1 and AQP5 expression. These results could serve as guidelines for the full understanding of ALI therapy by HBO, thus achieving maximized therapeutic efficiency.

TNF-α mediated increase of HIF-1α inhibits VASP expression, which reduces alveolar-capillary barrier function during acute lung injury (ALI)

Acute lung injury (ALI) is an inflammatory disorder associated with reduced alveolar-capillary barrier function and increased pulmonary vascular permeability. Vasodilator-stimulated phosphoprotein (VASP) is widely associated with all types of modulations of cytoskeleton rearrangement-dependent cellular morphology and function, such as adhesion, shrinkage, and permeability. The present studies were conducted to investigate the effects and mechanisms by which tumor necrosis factor-alpha (TNF-α) increases the tight junction permeability in lung tissue associated with acute lung inflammation. After incubating A549 cells for 24 hours with different concentrations (0–100 ng/mL) of TNF-α, 0.1 to 8 ng/mL TNF-α exhibited no significant effect on cell viability compared with the 0 ng/mL TNF-α group (control group). However, 10 ng/mL and 100 ng/mL TNF-α dramatically inhibited the viability of A549 cells compared with the control group (*p<0.05). Monolayer cell permeability assay results indicated that A549 cells incubated with 10 ng/mL TNF-α for 24 hours displayed significantly increased cell permeability (*p<0.05). Moreover, the inhibition of VASP expression increased the cell permeability (*p<0.05). Pretreating A549 cells with cobalt chloride (to mimic a hypoxia environment) increased protein expression level of hypoxia inducible factor-1α (HIF-1α) (*p<0.05), whereas protein expression level of VASP decreased significantly (*p<0.05). In LPS-induced ALI mice, the concentrations of TNF-α in lung tissues and serum significantly increased at one hour, and the value reached a peak at four hours. Moreover, the Evans Blue absorption value of the mouse lung tissues reached a peak at four hours. The HIF-1α protein expression level in mouse lung tissues increased significantly at four hours and eight hours (**p<0.001), whereas the VASP protein expression level decreased significantly (**p<0.01). Taken together, our data demonstrate that HIF-1α acts downstream of TNF-α to inhibit VASP expression and to modulate the acute pulmonary inflammation process, and these molecules play an important role in the impairment of the alveolar-capillary barrier.