Tanshinone IIA ameliorates seawater exposure-induced lung injury by inhibiting aquaporins (AQP) 1 and AQP5 expression in lung

Long COVID-19 gastrointestinal related disorders and traditional Chinese medicine: A network target-based approach

The significant number of individuals impacted by the pandemic makes prolonged symptoms after COVID-19 a matter of considerable concern. These are numerous and affect multiple organ systems. According to the World Health Organization (WHO), prolonged gastrointestinal issues are a crucial part of post-COVID-19 syndrome. The resulting disruption of homeostasis underscores the need for a therapeutic approach based on compounds that can simultaneously affect more than one target/node. The present review aimed to check for nutraceuticals possessing multiple molecular mechanisms helpful in relieving Long COVID-19-specific gastrointestinal symptoms. Specific plants used in Keywords Chinese Medicine (TCM) expected to be included in the WHO Global Medical Compendium were selected based on the following criteria: (1) they are widely used in the Western world as natural remedies and complementary medicine adjuvants; (2) their import and trade are regulated by specific laws that ensure quality and safety (3) have the potential to be beneficial in alleviating intestinal issues associated with Long COVID-19. Searches were performed in PubMed, Elsevier, Google Scholar, Scopus, Science Direct, and ResearchGate up to 2023. Cinnamomum cassia, Glycyrrhiza uralensis, Magnolia officinalis, Poria cocos, Salvia miltiorrhiza, Scutellaria baicalensis, and Zingiber officinalis were identified as the most promising for their potential impact on inflammation and oxidative stress. Based on the molecular mechanisms of the phytocomplexes and isolated compounds of the considered plants, their clinical use may lead to benefits in gastrointestinal diseases associated with Long COVID-19, thanks to a multiorgan and multitarget approach.

YuPingFengSan ameliorates LPS-induced acute lung injury and gut barrier dysfunction in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Yupingfengsan (YPFS) is a traditional Chinese medicine decoction. YPFS comprises Astragalus mongholicus Bunge (Huangqi), Atractylodes rubra Dekker (Baizhu), and Saposhnikovia divaricata (Turcz.ex Ledeb.) Schischk (Fangfeng). YPFS is commonly used to treat chronic obstructive pulmonary disease, asthma, respiratory infections, and pneumonia, but the mechanism of action remains unclear.

AIM OF THE STUDY

Acute lung injury (ALI) and its severe form of acute respiratory distress syndrome (ARDS) cause morbidity and mortality in critical patients. YPFS is a commonly used herbal soup to treat respiratory and immune system diseases. Nevertheless, the effect of YPFS on ALI remains unclear. This study aimed to investigate the effect of YPFS on lipopolysaccharide (LPS)-induced ALI in mice and elucidate its potential molecular mechanisms.

MATERIALS AND METHODS

The major components of YPFS were detected by High-performance liquid chromatography (HPLC). C57BL/6J mice were given YPFS for seven days and then treated with LPS. IL-1β, IL-6, TNF-α, IL-8, iNOS, NLRP3, PPARγ, HO-1, ZO-1, Occludin, Claudin-1, AQP3, AQP4, AQP5, ENaCα, ENaCβ, EnaCγ mRNA in lung and ZO-1, Occludin, Claudin-1, AQP3, AQP4, AQP5, ENaCα, ENaCβ, and EnaCγ mRNA in colon tissues were measured by Real-Time Quantitative PCR (RT-qPCR). The expressions of TLR4, MyD88, NOD-like receptor thermal protein domain associated protein 3 (NLRP3), ASC, MAPK signaling pathway, Nrf2, and HO-1 in the lung were detected by Western blot. Plasma inflammatory factors Interleukin (IL)-1β, IL-6, and Tumor Necrosis Factor-α (TNF-α) were determined by Enzyme-linked Immunosorbent Assay (ELISA). Lung tissues were processed for H & E staining, and colon tissues for HE, WGA-FITC, and Alcian Blue staining.

RESULTS

The results showed that YPFS administration alleviated lung injury and suppressed the production of inflammatory factors, including IL-1β, IL-6, and TNF-α. Additionally, YPFS reduced pulmonary edema by promoting the expressions of aquaporin and sodium channel-related genes (AQP3, AQP4, AQP5, ENaCα, ENaCβ, and EnaCγ). Further, YPFS intervention exhibited a therapeutic effect on ALI by inhibiting the activation of the NLRP3 inflammasome and MAPK signaling pathways. Finally, YPFS improved gut barrier integrity and suppressed intestinal inflammation in LPS-challenged mice.

CONCLUSIONS

YPFS protected mice against LPS-induced ALI by attenuating lung and intestinal tissue damage. This study sheds light on the potential application of YPFS to treat ALI/ARDS.

Tanshinone IIA changed the amniotic fluid volume and regulated expression of AQP1 and AQP3 in amniotic epithelium cells: a promising drug treating abnormal amniotic fluid volume

BACKGROUND

Many studies have confirmed the association of aquaporins (AQPs) with abnormal amniotic fluid volume (AFV). In our previous experiments, we found that Tanshinone IIA was able to regulate the expression of AQP1 and AQP3. However, the exact mechanism by which Tanshinone IIA regulates AQPs protein expression and its effect on AFV remains unclear. The purpose of this study was to investigate the effects of Tanshinone IIA on AFV and the possible molecular mechanism of regulation of AQP1 and AQP3.

METHODS

The expression of AQPs protein in the amniotic membranes was compared between pregnant women with normal pregnancy and those with isolated oligohydramnios. The AQP1 knockout (AQP1-KO) mice and wild-type (WT) mice were treated with saline or Tanshinone IIA (10 mg/kg) at 13.5GD and 16.5GD. Human amniotic epithelium cells (hAECs) from pregnant women with normal AFV and isolated oligohydramnios were incubated with 35 μmmol/L Tanshinone IIA or 25 mmol/L LiCl [inhibitor of glycogen synthetic kinase 3β (GSK-3β)]. The protein expressions of AQPs, GSK-3β, phospho-GSK-3β (Ser9) in fetal membranes of mice and human amniotic epithelium cells were detected by western blotting.

RESULTS

The expression of AQP1 protein in the amniotic membrane of isolated oligohydramnios was increased compared with normal pregnancy. The AFV in AQP1-KO mice is higher than that in WT mice. In wild-type mice, AFV in Tanshinone IIA group was significantly higher than that in control group, and AQP1 protein expression was significantly lower than that in control group, but in AQP1 knockout mice, Tanshinone IIA reduced amniotic fluid volume and AQP3 protein expression at 16.5GD. Tanshinone IIA reduced AQP1, AQP3 and p-GSK-3β (Ser9) protein expression in normal hAECs, and this effect was inhibited by LiCl. In hAECs with oligohydramnios, the down-regulation of AQP1 and up-regulation of AQP3 by Tanshinone IIA was independent of GSK-3β signaling pathway.

CONCLUSIONS

Tanshinone IIA may increase AFV in normal pregnancy by downregulating AQP1 protein expression in the fetal membranes, which may be associated with p-GSK-3β signaling pathway. But a larger AFV in AQP1-KO mice was significantly attenuated by Tanshinone IIA, which may be related to AQP3. Tanshinone IIA is a promising drug for the treatment of amniotic fluid abnormality.

Applicable Forensic Biomarker for Drowning Diagnosis: Extracellular Signal-Regulated Kinase 2 (ERK2)

Drowning is a common cause of accidental death worldwide, and it continues to be a serious public health problem. However, diagnosing drowning is a challenging task in forensic investigation because it is difficult to prove actual drowning and other submerged deaths with the autopsy techniques that are currently in use. Here, we show biomarkers that may be helpful for the diagnosis of drowning. We divided the experimental animals into four groups (drowning, postmortem submersion, hypoxia, and control) to evaluate the expression patterns of extracellular signal-regulated kinase 1/2 (ERK1/2). On gene expression analysis, only ERK2 was found to be significantly increased in the drowning groups compared to the other cases. In the immunoblot analysis, phosphorylated ERK2 (p-ERK2) was found to be upregulated in the drowning groups. Immunohistochemical staining also showed that p-ERK in alveolar cells revealed a granular pattern in the drowning groups. However, the expression pattern of ERK2 over time after drowning differed between the freshwater and seawater drowning groups. Taken together, these results indicate that ERK2 may be useful for distinguishing between drowning and postmortem submersion if the postmortem interval (PMI) of drowning is short. Conversely, if the PMI is long from the time that death occurs until the discovery of dead bodies, it is possibly more helpful for identifying between freshwater and seawater drowning.

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.

Significance of Pulmonary Endothelial Injury and the Role of Cyclooxygenase-2 and Prostanoid Signaling

The endothelium plays a key role in the dynamic balance of hemodynamic, humoral and inflammatory processes in the human body. Its central importance and the resulting therapeutic concepts are the subject of ongoing research efforts and form the basis for the treatment of numerous diseases. The pulmonary endothelium is an essential component for the gas exchange in humans. Pulmonary endothelial dysfunction has serious consequences for the oxygenation and the gas exchange in humans with the potential of consecutive multiple organ failure. Therefore, in this review, the dysfunction of the pulmonary endothel due to viral, bacterial, and fungal infections, ventilator-related injury, and aspiration is presented in a medical context. Selected aspects of the interaction of endothelial cells with primarily alveolar macrophages are reviewed in more detail. Elucidation of underlying causes and mechanisms of damage and repair may lead to new therapeutic approaches. Specific emphasis is placed on the processes leading to the induction of cyclooxygenase-2 and downstream prostanoid-based signaling pathways associated with this enzyme.

Isolation and Comprehensive in Silico Characterisation of a New 3-Hydroxy-3-Methylglutaryl-Coenzyme A Reductase 4 (HMGR4) Gene Promoter from Salvia miltiorrhiza: Comparative Analyses of Plant HMGR Promoters

Salvia miltiorrhiza synthesises tanshinones with multidirectional therapeutic effects. These compounds have a complex biosynthetic pathway, whose first rate limiting enzyme is 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR). In the present study, a new 1646 bp fragment of the S. miltiorrhiza HMGR4 gene consisting of a promoter, 5′ untranslated region and part of a coding sequence was isolated and characterised in silico using bioinformatics tools. The results indicate the presence of a TATA box, tandem repeat and pyrimidine-rich sequence, and the absence of CpG islands. The sequence was rich in motifs recognised by specific transcription factors sensitive mainly to light, salicylic acid, bacterial infection and auxins; it also demonstrated many binding sites for microRNAs. Moreover, our results suggest that HMGR4 expression is possibly regulated during flowering, embryogenesis, organogenesis and the circadian rhythm. The obtained data were verified by comparison with microarray co-expression results obtained for Arabidopsis thaliana. Alignment of the isolated HMGR4 sequence with other plant HMGRs indicated the presence of many common binding sites for transcription factors, including conserved ones. Our findings provide valuable information for understanding the mechanisms that direct transcription of the S. miltiorrhiza HMGR4 gene.

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.

Natural product derived phytochemicals in managing acute lung injury by multiple mechanisms

Acute lung injury (ALI) and its more severe form, acute respiratory distress syndrome (ARDS) as common life-threatening lung diseases with high mortality rates are mostly associated with acute and severe inflammation in lungs. With increasing in-depth studies of ALI/ARDS, significant breakthroughs have been made, however, there are still no effective pharmacological therapies for treatment of ALI/ARDS. Especially, the novel coronavirus pneumonia (COVID-19) is ravaging the globe, and causes severe respiratory distress syndrome. Therefore, developing new drugs for therapy of ALI/ARDS is in great demand, which might also be helpful for treatment of COVID-19. Natural compounds have always inspired drug development, and numerous natural products have shown potential therapeutic effects on ALI/ARDS. Therefore, this review focuses on the potential therapeutic effects of natural compounds on ALI and the underlying mechanisms. Overall, the review discusses 159 compounds and summarizes more than 400 references to present the protective effects of natural compounds against ALI and the underlying mechanism.

Oxycodone attenuates vascular leak and lung inflammation in a clinically relevant two-hit rat model of acute lung injury

BACKGROUND

Oxycodone is a synthetic opioid receptor agonist that exerts antinociceptive activity via κ-, μ- and δ-opioid receptors (KOR, MOR and DOR, respectively). Activation of MOR has been reported to provide protection against acute lung injury (ALI). We hypothesized that pretreatment with oxycodone would attenuate lung injury at the level of alveolar tight junctions (TJs) and aquaporins (AQPs) and investigated this possibility in a two-hit model of ALI induced by lipopolysaccharide (LPS) and mechanical ventilation (MV).

METHOD

Male Sprague Dawley rats and A59 cells were divided into 6 groups: the control group, ALI group, oxycodone-pretreated group, and oxycodone/κ-, μ-, or δ-opioid receptor antagonist-pretreated groups. The rats were pretreated with oxycodone 30 min before intravenous injection of LPS and then allowed to recover for 24 h prior to MV, establishing a two-hit model of ALI. The cells were similarly treated with oxycodone (with or without antagonists) 30 min after exposure to lipopolysaccharide. The cells were cyclically stretched 24 h later to mirror the in vivo MV protocol.

RESULTS

Oxycodone alleviated the histological lung changes in the rats with ALI and decreased pulmonary microvascular permeability both in vivo and in vitro. Oxycodone upregulated the expression of claudin-5, ZO-1, AQP1, and AQP5 but downregulated the expression of TNF-α, IL-1β, TLR4, NF-κB, MMP9, and caspase-3 and suppressed endothelial apoptosis in vivo and in vitro. These protective effects of oxycodone were partly eliminated by KOR and MOR antagonists but not by DOR antagonists.

CONCLUSION

Oxycodone pretreatment appears to act via κ- and μ-opioid receptors to ameliorate LPS- and MV-induced lung injury by suppressing inflammation and apoptosis, and this protective effect might be mediated through the inhibition of the TLR4/NF-κB pathways.

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.

Qidonghuoxue Decoction Ameliorates Pulmonary Edema in Acute Lung Injury Mice through the Upregulation of Epithelial Sodium Channel and Aquaporin-1

QDHX decoction is an effective traditional Chinese medicine that has been used to treat ALI, a disease characterized by pulmonary edema and inflammation. In this study, the aim is to elucidate the molecular mechanisms of QDHX decoction on improving the alveolar-capillary membrane permeability and alleviating inflammatory response. The BALB/c mice were divided into five groups including the control group, ALI group, ALI + low-dose QDHX decoction, ALI + high-dose QDHX decoction, and ALI + dexamethasone. When the animals were sacrificed, the pathology and wet/dry of lung tissue were tested and confirmed Ali model, the LDH and nucleated cells in BALF, and TNF-α and IL-1β in serum; α-ENaC and AQP-1 in lung tissue were examined. In the results, QDHX decoction downregulated the cytokine such as TNF-α and IL-1β, reduced the nucleated cells, and some biochemical parameters of the BALF. It also ameliorated the ENaC-α and AQP-1 expression induced by LPS in primary epithelial cells. These findings may provide new insights into the application of QDHX decoction for the prevention and treatment of LPS-related ALI.

Dexamethasone Upregulates the Expression of Aquaporin4 by Increasing SUMOylation in A549 Cells

Dexamethasone can alleviate the severity of bronchial and alveolar edema and therefore is widely applied in the treatment of various exudative diseases including pulmonary edema. However, the effectiveness of dexamethasone is still being questioned and its mechanism is not fully understood. Aquaporins (AQPs) are mainly responsible for the transmembrane transport of water, which is tightly associated with pulmonary edema. Small ubiquitin-like modifiers (SUMOs) are considered to play a protective role in some pathological conditions. In this study, we demonstrated that dexamethasone can upregulate the expression of AQPs in A549 cells by inducing SUMOylation. We found that a low dose of dexamethasone significantly upregulated the levels of SUMOylation and AQP expression in A549 cells, accompanied by a translocation of SUMOs from the cytoplasm to the nucleus. We also explored the possible relation between SUMOylation and AQPs. Knockdown of SUMO2/3 by RNA interference decreased the level of AQP4 in A549 cells after dexamethasone stimulation. Together, our findings demonstrated that AQP4 expression was upregulated in A549 cells exposed to dexamethasone, and SUMOylation may participate in the regulation of AQP4.

Tanshinone IIA alleviates blast-induced inflammation, oxidative stress and apoptosis in mice partly by inhibiting the PI3K/Akt/FoxO1 signaling pathway

Although Tanshinone IIA (Tan IIA) has been associated with inflammation, oxidative stress and apoptosis, the effects of Tan IIA on lung blast injury remain uncertain. In this study, we explored the effects of Tan IIA on lung blast injury, studied its possible molecular mechanisms. Fifty C57BL/6 mice were randomly divided into the control, blast, blast + Tan IIA, blast + LY294002 (a PI3K inhibitor), or blast + Tan IIA + LY294002 groups. Serum and lung samples were collected 48 h after blast injury. The data showed that Tan IIA significantly inhibited blast-induced increases in the lung weight/body weight and wet/dry (W/D) weight ratios, decreased the CD44^-and CD163-positive inflammatory cell infiltration in the lungs, reduced the IL-1β, TNF-α and IL-6 expression, and enhanced IL-10 expression. Tan IIA also significantly alleviated the increases in MDA5 and IRE-a and the decrease in SOD-1 and reversed the low Bcl-2 expression and the high Bax and Caspase-3 expressions. Additionally, Tan IIA significantly decreased p-PI3K and p-Akt expression and increased p-FoxO1 expression. More importantly, both LY294002 and Tan IIA pretreatment markedly protected against blast-induced inflammation, oxidative stress and apoptosis in lung blast injury. These results suggest that Tan IIA protects against lung blast injury, which may be partly mediated by inhibiting the PI3K/Akt/FoxO1 signaling pathway.

Thyroid Function Modulates Lung Fluid and Alveolar Viscoelasticity in Mechanically Ventilated Rat

BACKGROUND

Mechanical ventilation (MV) is life saving; yet it may induce severe lung injury and lead to multisystem organ failure and death. Thyroid hormones (THs) promote alveolar fluid clearance and alleviates hypoxia-induced lung injury. Given that the mechanism involved in hypoxia-induced lung injury is different from that of ventilator-induced lung injury, we examined the effects of thyroid function on lung extravascular fluid (LF), aquaporin 5 (AQP 5) expression, and alveolar viscoelasticity (AVE) in mechanically ventilated rat.

METHODS

Hypothyroid (hypo) and hyperthyroid (hyper) animals were generated by administration of metimazole and L-thyroxine, respectively. Lung injury was induced by high-tidal volume MV. The LF was estimated by lung wet weight-to-dry weight ratio assessment. Expression of AQP 5 was evaluated by western blotting and in situ immunohistochemistry. The AVE was judged by elastic lung pressure/volume curve recording.

RESULTS

Injurious MV significantly reduced lung AQP 5 expression and altered LF and AVE in a thyroid function-dependent manner. Regardless of animals' ventilation mode, hyper state caused significant reductions in LF and lung AQP 5 protein. It also improved AVE irrespective of animals' ventilation mode. The effects of hypo condition on LF, AQP 5 expression, and AVE were in contrast to that of hyper state.

CONCLUSIONS

These data indicate that thyroid function has profound effects on LF, AQP 5, and AVE in mechanically ventilated lungs. Given that the effects of thyroidal status were as prominent as that of injurious MV, we suggest that thyroid function should be considered when patients are to be subjected to MV.

Acupoint Catgut Embedding Improves the Lipopolysaccharide-Induced Acute Respiratory Distress Syndrome in Rats

Background

This study investigated the potential therapeutic effects of acupoint catgut embedding (ACE) at ST36 and BL13 on lipopolysaccharide- (LPS-) induced acute respiratory distress syndrome (ARDS) in rats.

Materials and Methods

Male Sprague-Dawley rats were randomized into the normal saline (NS group with a sham procedure), lipopolysaccharide (LPS group with a sham procedure), and LPS plus ACE (LPS+ACE with ACE at bilateral BL13 and ST36 acupoints one day before LPS injection) groups. After intratracheal instillation of normal saline or LPS (0.5 mg/kg), all rats were subjected to mechanical ventilation for 4 h. Their blood gas was analyzed before and after lung injury, and their lung pressure-volumes were measured longitudinally. The levels of TNF-α, IL-6, IL-10, and phosphatidylcholine (PC) and total proteins (TP) in bronchial alveolar lavage fluid (BALF) were assessed. Their wet to dry lung weight ratios, histology, myeloperoxidase (MPO), superoxide dismutase (SOD) activity, and malondialdehyde (MDA) levels were measured. Their lung aquaporin 1 (AQP1) and Occludin protein levels were analyzed.

Results

LPS administration significantly decreased the ratios of PaO₂/FiO₂ and pressure-volumes and induced lung inflammation and injury by increased concentrations of TNF-α, IL-6, IL-10, and TP in BALF and MPO and MDA in the lung but decreased PC in BALF and SOD activity in the lungs. LPS also reduced AQP1 and Occludin protein levels in the lung of rats. In contrast, ACE significantly mitigated the LPS-induced lung injury, inflammation, and oxidative stress and preserved the AQP1 and Occludin contents in the lung of rats.

Conclusions

ACE significantly improved respiratory function by mitigating inflammation and oxidative stress and preserving AQP1 and Occludin expression in the lung in a rat model of LPS-induced ARDS.

Aquaporin 5 -1364A/C Promoter Polymorphism Is Associated with Pulmonary Inflammation and Survival in Acute Respiratory Distress Syndrome

WHAT WE ALREADY KNOW ABOUT THIS TOPIC

Acute respiratory distress syndrome is defined according to clinical criteria, but lack of precise characterization may contribute to negative trials and impede personalized care. Polymorphisms of aquaporin-5, a key mediator of inflammation, may impact outcome.

WHAT THIS ARTICLE TELLS US THAT IS NEW

In acute respiratory distress syndrome attributable to bacterial pneumonia, the C-allele of the aquaporin-5 -1364A/C promoter polymorphism is associated with less pulmonary inflammation and greater survival. This may improve characterization of acute respiratory distress syndrome and ultimately facilitate individualized care.

BACKGROUND

The aquaporin-5 (AQP5) -1364A/C promoter single-nucleotide polymorphism is associated with an altered AQP5 expression and mortality in sepsis. Because AQP5 expression alters neutrophil cell migration, it could affect pulmonary inflammation and survival in bacterially evoked acute respiratory distress syndrome. Accordingly, the authors tested the hypotheses that the AC/CC genotype in patients with bacterially evoked pneumonia resulting in acute respiratory distress syndrome is associated with (1) attenuated pulmonary inflammation and (2) higher 30-day survival.

METHODS

In this prospective, observational study, bronchoalveolar lavage and blood sampling were performed within 24 h of intensive care unit admission. In 136 Caucasian patients with bacterially evoked acute respiratory distress syndrome, genotype of the AQP5 -1364A/C promoter polymorphism, bronchoalveolar lavage total protein, albumin, white cell concentrations, and lactate dehydrogenase activity were measured to evaluate the relationship between genotypes and survival.

RESULTS

AC/CC patients as well as survivors showed lower bronchoalveolar lavage protein (0.9 mg/ml vs. 2.3 mg/ml, P < 0.001 and 1.6 mg/ml vs. 2.6 mg/ml, P = 0.035), albumin (0.2 mg/ml vs. 0.6 mg/ml, P = 0.019 and 0.3 mg/ml vs. 0.6 mg/ml, P = 0.028), leukocytes (424 /ml vs. 1,430/ml; P = 0.016 and 768 /ml vs. 1,826/ml; P = 0.025), and lactate dehydrogenase activity (82 U/l vs. 232 U/l; P = 0.006 and 123 U/l vs. 303 U/l; P = 0.020). Thirty-day survival was associated with AQP5 -1364A/C genotypes (P = 0.005), with survival of 62% for AA genotypes (58 of 93) but 86% for C-allele carriers (37 of 43). Furthermore, multiple proportional hazard analysis revealed the AA genotype was at high risk for death within 30 days (hazard ratio, 3.53; 95% CI, 1.38 to 9.07; P = 0.009).

CONCLUSIONS

In acute respiratory distress syndrome attributable to bacterial pneumonia, the C-allele of the AQP5 -1364A/C promoter polymorphism is associated with an attenuated pulmonary inflammation and higher 30-day survival. Thus, the AQP5 genotype impacts on inflammation and prognosis in acute respiratory distress syndrome.

Escin suppresses HMGB1-induced overexpression of aquaporin-1 and increased permeability in endothelial cells

Escin, a natural triterpene saponin mixture obtained from the horse chestnut tree (Aesculus hippocastanum), has been used for the treatment of chronic venous insufficiency (CVI), hemorrhoids, and edema. However, it is unclear how escin protects against endothelial barrier dysfunction induced by pro‐inflammatory high mobility group protein 1 (HMGB1). Here, we report that escin can suppress (a) HMGB1‐induced overexpression of the aquaporin‐1 (AQP1) water channel in endothelial cells and (b) HMGB1‐induced increases in endothelial cell permeability. This is the first report that escin inhibits AQP1 and alleviates barrier dysfunction in HMGB1‐induced inflammatory response.

Potential forensic application of receptor for advanced glycation end products (RAGE) and aquaporin 5 (AQP5) as novel biomarkers for diagnosis of drowning

Drowning is the most common cause of unnatural death worldwide. There is no single biomarker to diagnose drowning, so the diagnosis of drowning is one of the most difficult tasks in forensic medicine. Especially, distinguishing a victim of drowning from a body disposed of in water following death remains a problem. The objective of this study was to identify specific biomarkers of drowning compared with other causes of death such as hypoxia and postmortem submersion. The present study investigated the intrapulmonary expression of receptor for advanced glycation end products (RAGE), aquaporin-5 (AQP5), surfactant protein-A (SP-A), interleukin 6 (IL-6) and interleukin 1β (IL-1β) as markers of drowning. In animal experiments, all rats (n = 45) were classified into four groups (drowning, postmortem-submersion, hypoxia and control group). The lungs of experimental animals were analyzed as mRNA expression, immunoblot expression and immunohistochemical staining. qRT-PCR demonstrated increased mRNA expression of RAGE and AQP5 in drowning group compared with that in control, hypoxia and postmortem-submersion group, but not other molecules. Western blotting also showed high expression of RAGE and AQP5 in drowning group, immunostaining of RAGE and AQP5 was highly detected in a linear pattern in type I alveolar epithelial cells, compared with control and postmortem-submersion group. These observations indicate a difference of expression in pulmonary molecular pathology compared with other causes, suggesting RAGE and AQP5 may be useful for differentiation between drowning and postmortem-submersion.

Lipoxin A4 Ameliorates Lipopolysaccharide-Induced A549 Cell Injury through Upregulation of N-myc Downstream-Regulated Gene-1

Background:

Lipoxin A4 (LXA4) can alleviate lipopolysaccharide (LPS)-induced acute lung injury (ALI) and acute respiratory distress syndrome through promoting epithelial sodium channel (ENaC) expression in lung epithelial cells. However, how LXA4 promote ENaC expression is still largely elusive. The present study aimed to explore genes and signaling pathway involved in regulating ENaC expression induced by LXA4.

Methods:

A549 cells were incubated with LPS and LXA4, or in combination, and analyzed by quantitative real-time polymerase chain reaction (qRT-PCR) of ENaC-α/γ. Candidate genes affected by LXA4 were explored by transcriptome sequencing of A549 cells. The critical candidate gene was validated by qRT-PCR and Western blot analysis of A549 cells treated with LPS and LXA4 at different concentrations and time intervals. LXA4 receptor (ALX) inhibitor BOC-2 was used to test induction of candidate gene by LXA4. Candidate gene siRNA was adopted to analyze its influence on A549 viability and ENaC-α expression. Phosphoinositide 3-kinase (PI3K) inhibitor LY294002 was utilized to probe whether the PI3K signaling pathway was involved in LXA4 induction of candidate gene expression.

Results:

The A549 cell models of ALI were constructed and subjected to transcriptome sequencing. Among candidate genes, N-myc downstream-regulated gene-1 (NDRG1) was validated by real-time-PCR and Western blot. NDRG1 mRNA was elevated in a dose-dependent manner of LXA4, whereas BOC-2 antagonized NDRG1 expression induced by LXA4. NDRG1 siRNA suppressed viability of LPS-treated A549 cells (treatment vs. control, 0.605 ± 0.063 vs. 0.878 ± 0.083, P = 0.040) and ENaC-α expression (treatment vs. control, 0.458 ± 0.038 vs. 0.711 ± 0.035, P = 0.008). LY294002 inhibited NDRG1 (treatment vs. control, 0.459 ± 0.023 vs. 0.726 ± 0.020, P = 0.001) and ENaC-α (treatment vs. control, 0.236 ± 0.021 vs. 0.814 ± 0.025, P < 0.001) expressions and serum- and glucocorticoid-inducible kinase 1 phosphorylation (treatment vs. control, 0.442 ± 0.024 vs. 1.046 ± 0.082, P = 0.002), indicating the PI3K signaling pathway was involved in regulating NDRG1 expression induced by LXA4.

Conclusion:

Our research uncovered a critical role of NDRG1 in LXA4 alleviation of LPS-induced A549 cell injury through mediating PI3K signaling to restore ENaC expression.

Tanshinone IIA attenuates paraquat‑induced acute lung injury by modulating angiotensin‑converting enzyme 2/angiotensin‑(1‑7) in rats

Tanshinone IIA (TIIA) is an active compound that can be isolated from the Chinese herb, Salvia miltiorrhizae Bunge, also known as danshen. Previous studies have demonstrated that TIIA can effectively attenuate bleomycin‑induced pulmonary fibrosis in rats. However, it has not been determined whether TIIA can attenuate paraquat (PQ)‑induced acute lung injury (ALI). In the present study, the protective effects exhibited by TIIA on PQ‑induced ALI, as well as its underlying mechanisms, were investigated using Sprague‑Dawley (SD) rats. ALI animal models using rats were established via administration of PQ. Adult male SD rats were randomly divided into three groups: A control group, a PQ group and a PQ + TIIA group. Total cell count, total protein levels and lactic dehydrogenase (LDH) levels in bronchoalveolar lavage fluid (BALF), as well as myeloperoxidase (MPO) activity in lung tissues were determined. Lung histological alterations were also investigated. Angiotensin converting enzyme 2 (ACE2) and Angiotensin 1‑7 [Ang‑(1‑7)] expression levels in the lung were also analyzed. The results demonstrated that administration of PQ induced marked histological alterations, and markedly increased neutrophil infiltration, lung wet/dry weight ratio, total cell count, protein content and LDH levels in BALF. In addition, PQ was revealed to significantly decrease ACE2 and Ang‑(1‑7) expression levels in lung tissues. However, it was demonstrated that TIIA attenuated these effects. Therefore, the results of the present study suggest that that TIIA may exhibit a therapeutic effect regarding PQ‑induced ALI in rats, and that ACE2 and Ang‑(1‑7) may be involved in the underlying mechanisms of this effect.

Emodin ameliorates acute lung injury induced by severe acute pancreatitis through the up-regulated expressions of AQP1 and AQP5 in lung

The present study investigates the ameliorating effects of emodin on acute lung injury (ALI) induced by severe acute pancreatitis (SAP). An ALI rat model was constructed by sodium ursodeoxycholate and they were divided into four groups: SHAM, ALI, emodin and dexamethasone (DEX) (n=24 per group). Blood samples and lung tissues were collected 6, 12 and 24 hours after the induction of SAP-associated ALI. Lung wet/dry ratio, blood gases, serum amylase and tumor necrosis factor-α (TNF-α) were measured at each time point. The expressions of AQP1 and AQP5 in lung tissue were detected by immunohistochemical staining, western blotting and real-time PCR. As the results show, there were no statistical differences in the levels of serum amylase, lung wet/dry ratio, blood gases indexes, serum TNF-α and pathological changes between emodin and DEX groups. However, significant differences were observed when compared with the ALI group. AQP1 and AQP5 expressions were significantly increased and lung oedemas were alleviated with the treatment of emodin and DEX. The expressions of AQP1 and AQP5 were significantly decreased in SAP-associated ALI rats. Emodin up-regulated the expression of AQP1 and AQP5, it could reduce pulmonary oedema and ameliorate SAP-induced ALI. Regulations on AQP1 and AQP5 expression had a great value in clinical application.

Seawater-drowning-induced acute lung injury: From molecular mechanisms to potential treatments

Drowning is a crucial public safety problem and is the third leading cause of accidental fatality, claiming ~372,000 lives annually, worldwide. In near-drowning patients, acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) is one of the most common complications. Approximately 1/3 of near-drowning patients fulfill the criteria for ALI or ARDS. In the present article, the current literature of near-drowning, pathophysiologic changes and the molecular mechanisms of seawater-drowning-induced ALI and ARDS was reviewed. Seawater is three times more hyperosmolar than plasma, and following inhalation of seawater the hyperosmotic seawater may cause serious injury in the lung and alveoli. The perturbing effects of seawater may be primarily categorized into insufficiency of pulmonary surfactant, blood-air barrier disruption, formation of pulmonary edema, inflammation, oxidative stress, autophagy, apoptosis and various other hypertonic stimulation. Potential treatments for seawater-induced ALI/ARDS were also presented, in addition to suggestions for further studies. A total of nine therapeutic strategies had been tested and all had focused on modulating the over-activated immunoreactions. In conclusion, seawater drowning is a complex injury process and the exact mechanisms and potential treatments require further exploration.

Expression of aquaporins 1 and 5 in a model of ventilator-induced lung injury and its relation to tidal volume

NEW FINDINGS

What is the central question of this study? Although different studies have attempted to find factors that influence the expression of aquaporins (AQPs) in the lung in different situations, to date no research group has explored the expression of AQP1 and AQP5 jointly in rats mechanically ventilated with different tidal volumes in a model of ventilator-induced lung injury. What is the main finding? Mechanical ventilation with a high tidal volume causes lung injury and oedema, increasing lung permeability. In rats ventilated with a high tidal volume, the pulmonary expression of AQP1 decreases. We analysed the expression of aquaporins 1 and 5 and its relation with tidal volume in a model of ventilator-induced lung injury. Forty-two rats were used. Six non-ventilated animals were killed (control group). The remaining rats were ventilated for 2 h with different tidal volumes (group 7ML with 7 ml kg^-1 and group 20ML with 20 ml kg^-1 ) and a respiratory rate of 90 breaths min^-1 . Lung oedema was measured, and the expression of AQP1 and AQP5 was determined by Western immunoblotting and measurement of mRNA. Lung oedema and alveolar-capillary membrane permeability were significantly increased in the animals of group 20ML compared with the control group. Expression of AQP1 was decreased in groups 7ML and 20ML compared with the control group. In conclusion, mechanical ventilation with a high tidal volume causes lung injury and oedema, increasing lung permeability. In rats ventilated with a high tidal volume, the pulmonary expression of AQP1 decreases.

Identification of distinct genes associated with seawater aspiration‑induced acute lung injury by gene expression profile analysis

Seawater aspiration-induced acute lung injury (ALI) is a syndrome associated with a high mortality rate, which is characterized by severe hypoxemia, pulmonary edema and inflammation. The present study is the first, to the best of our knowledge, to analyze gene expression profiles from a rat model of seawater aspiration-induced ALI. Adult male Sprague-Dawley rats were instilled with seawater (4 ml/kg) in the seawater aspiration-induced ALI group (S group) or with distilled water (4 ml/kg) in the distilled water negative control group (D group). In the blank control group (C group) the rats' tracheae were exposed without instillation. Subsequently, lung samples were examined by histopathology; total protein concentration was detected in bronchoalveolar lavage fluid (BALF); lung wet/dry weight ratios were determined; and transcript expression was detected by gene sequencing analysis. The results demonstrated that histopathological alterations, pulmonary edema and total protein concentrations in BALF were increased in the S group compared with in the D group. Analysis of differential gene expression identified up and downregulated genes in the S group compared with in the D and C groups. A gene ontology analysis of the differential gene expression revealed enrichment of genes in the functional pathways associated with neutrophil chemotaxis, immune and defense responses, and cytokine activity. Kyoto Encyclopedia of Genes and Genomes analysis revealed that the cytokine-cytokine receptor interaction pathway was one of the most important pathways involved in seawater aspiration-induced ALI. In conclusion, activation of the cytokine-cytokine receptor interaction pathway may have an essential role in the progression of seawater aspiration-induced ALI, and the downregulation of tumor necrosis factor superfamily member 10 may enhance inflammation. Furthermore, IL-6 may be considered a biomarker in seawater aspiration-induced ALI.

Effect of emodin on Aquaporin 5 expression in rats with sepsis-induced acute lung injury

OBJECTIVE

To investigate the effects of emodin on aquaporin 5 (AQP5) expression in rats with sepsis-induced acute lung injury.

METHODS

We divided 60 adult male Sprague-Dawley rats, weighing 200-230 g, into four groups: control, sham surgery, model and emodin groups (n = 15 for each). We created a sepsis model with cecal ligation and puncture; the sham surgery group had their cecums replaced after exposure outside the abdominal cavity. Each group was further divided into three subgroups (n = 5 for each) and expressions of AQP5 mRNA and proteins in lung tissue were measured by real-time fluorescence polymerase chain reaction and western blot at 6,12 and 24 h after surgery.

RESULTS

AQP5 expression did not change over time in the control group and sham surgery group, but decreased over time in the model group. The lowest expression was found in 12-h subgroup, which significantly differed from the 6-h subgroup (P < 0.01). Compared with the model group, AQP5 expression in the emodin group was significantly higher in all the subgroups (all P < 0.01). Expressions in the 12-h subgroup were the highest, and significantly differed from the other subgroups. We found that lung tissue damage, such as pulmonary edema, alveolar damage and the exudation of red blood cells in pulmonary interstitium and alveolar, was significantly milder in the emodin group under light microscope than the model group.

CONCLUSION

AQP5 expression was significantly down-regulated in rats with sepsis-induced acute lung injury induced by cecal ligation and puncture. Early prophylactic use of emodin can significantly enhance the AQP5 expression, thus effectively reducing the degree of pulmonary edema in septic rats.

Activation of TRPV1-dependent calcium oscillation exacerbates seawater inhalation-induced acute lung injury

Calcium is an important second messenger and it is widely recognized that acute lung injury (ALI) is often caused by oscillations of cytosolic free Ca²⁺. Previous studies have indicated that the activation of transient receptor potential-vanilloid (TRPV) channels and subsequent Ca²⁺ entry initiates an acute calcium-dependent permeability increase during ALI. However, whether seawater exposure induces such an effect through the activation of TRPV channels remains unknown. In the current study, the effect of calcium, a component of seawater, on the inflammatory reactions that occur during seawater drowning-induced ALI, was examined. The results demonstrated that a high concentration of calcium ions in seawater increased lung tissue myeloperoxidase activity and the secretion of inflammatory mediators, such as tumor necrosis factor-α (TNF-α) and interleukin (IL)-1β and IL-6. Further study demonstrated that the seawater challenge elevated cytosolic Ca²⁺ concentration, indicated by [Ca²⁺]c, by inducing calcium influx from the extracellular medium via TRPV1 channels. The elevated [Ca²⁺c] may have resulted in the increased release of TNF-α and IL-1β via increased phosphorylation of nuclear factor-κB (NF-κB). It was concluded that a high concentration of calcium in seawater exacerbated lung injury, and TRPV1 channels were notable mediators of the calcium increase initiated by the seawater challenge. Calcium influx through TRPV1 may have led to greater phosphorylation of NF-κB and increased release of TNF-α and IL-1β.

Salvia miltiorrhiza: Traditional medicinal uses, chemistry, and pharmacology

Salvia miltiorrhiza Bunge (SM) is a very popular medicinal plant that has been extensively applied for many years to treat various diseases, especially coronary heart diseases and cerebrovascular diseases, either alone or in combination with other Chinese plant-based medicines. Although a large number of studies on SM have been performed, they are scattered across a variety of publications. The present review is an up-to-date summary of the published scientific information about the traditional uses, chemical constituents, pharmacological effects, side effects, and drug interactions with SM, in order to lay the foundation for further investigations and better utilization of SM. SM contains diverse chemical components including diterpenoid quinones, hydrophilic phenolic acids, and essential oils. Many pharmacological studies have been done on SM during the last 30 years, focusing on the cardiovascular and cerebrovascular effects, and the antioxidative, neuroprotective, antifibrotic, anti-inflammatory, and antineoplastic activities. The research results strongly support the notion that SM has beneficial therapeutic properties and has a potential of being an effective adaptogenic remedy.

Epigallocatechin-3-gallate suppresses alveolar epithelial cell apoptosis in seawater aspiration-induced acute lung injury via inhibiting STAT1-caspase-3/p21 associated pathway

The apoptosis of alveolar epithelial cells is important in seawater aspiration‑induced acute lung injury (ALI). The present study aimed to investigate whether epigallocatechin-3-gallate (EGCG) is able to suppress apoptosis in alveolar epithelial cells in seawater aspiration‑induced ALI in vivo and in vitro, and the possible mechanisms underlying it. The results indicated that seawater aspiration‑induced ALI in rats is accompanied by increased apoptosis in lung tissue cells and the expression of apoptosis‑associated proteins, caspase‑3 and p21. EGCG pretreatment significantly ameliorated seawater aspiration‑induced ALI. Furthermore, EGCG decreased seawater aspiration‑induced apoptosis and the expression of caspase‑3 and p21 in lung tissue cells. Seawater‑challenged A549 cells experienced increased apoptosis and elevated levels of phosphorylated‑signal transducer and activator of transcription 1 (P‑STAT1). EGCG pretreatment of the cells resulted in significantly decreased seawater‑induced apoptosis and lower levels of STAT1 and P‑STAT1 in A549 cells. This suggests that EGCG suppresses alveolar epithelial cell apoptosis in seawater aspiration‑induced ALI via inhibiting the STAT1-caspase-3/p21 associated pathway.

3,5,4'-Tri-O-acetylresveratrol decreases seawater inhalation-induced acute lung injury by interfering with the NF-κB and i-NOS pathways

Drowning is a cause of accidental mortality. However, survival may result in acute lung injury. The aim of the present study was to evaluate the effects of 3,5,4'-tri-O-acetylresveratrol (AC-Res) on acute lung injury (ALI) induced by seawater inhalation in rats. ALI models were established by the tracheal instillation of artificial seawater with or without 50 mg/kg AC-Res pretreatment for 7 days. Lung samples from different groups were harvested 4 h after the model was established. Histological changes, blood vessel permeability, inflammatory factor secretion and expression states of the nuclear factor-κB (NF-κB) and inducible NOS (i-NOS) pathway were assessed to evaluate seawater‑induced lung injury and the protective effects of acetylated resveratrol. The results showed that seawater inspiration led to physiological structure changes and an increased permeability of blood vessels. In addition, seawater stimulation enhanced the expression levels of nitric oxide (NO), tumor necrosis factor α (TNF-α) and interleukin-1 β (IL-1β) secretion in vitro and in vivo. Notably, seawater inhalation increased NF-κB and i-NOS expression in lungs and cells. On the other hand, pretreatment of AC-Res inhibited the abnormal expression of the NF-κB and i-NOS pathways, followed by decreased NO, TNF-α and IL-1β secretion, protein and cell content in bronchoalveolar lavage fluid (BALF) and Evans blue, protein and cell infiltration from blood vessels into lung tissues. The results therefore suggest that AC-Res attenuated seawater inhalation induced‑ALI by interfering with the NF-κB and i-NOS pathways.

PBEF promotes the apoptosis of pulmonary microvascular endothelial cells and regulates the expression of inflammatory factors and AQP1 through the MAPK pathways

Pre-B cell colony-enhancing factor (PBEF) has been shown to have a variety of biological functions. Studies have proven that PBEF plays a functional role in acute lung injury (ALI). Therefore, in this study, we aimed to confirm the importance of PBEF in ALI. The effects of PBEF overexpression on the apoptosis of human pulmonary microvascular endothelial cells (HPMECs) were analyzed by flow cytometry, and the results indicated that PBEF promoted the apoptosis of HPMECs, which aggravated the development of ALI. Comparative experiments involving increasing and decreasing PBEF expression demonstrated that PBEF promoted the expression of inflammatory factors, such as interleukin (IL)‑1β, IL‑6 and IL‑8 in the HPMECs , thus intensifying the inflammatory response. PBEF also inhibited the expression of aquaporin 1 (AQP1), which caused a dysfunction and imbalance in water transport. Moreover, we also found that tumor necrosis factor (TNF)‑α promoted the expression of PBEF in the HPMECs. After blocking the mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K) pathways, we found that PBEF regulated the expression of inflammatory factors and AQP1, mainly through the MAPK pathways. Taken together, these results demonstrate that the increase in intracellular PBEF expression promoted the apoptosis of HPMECs and the expression of inflammatory factors and thus enhanced the inflammatory response and inhibited the expression of AQP1, which resulted in abnormal water transport, diminishing the regulatory effects of AQP1 on water transport.

Tanshinone IIA therapeutically reduces LPS-induced acute lung injury by inhibiting inflammation and apoptosis in mice

AIM

To study the effects of tanshinone IIA (TIIA) on lipopolysaccharide (LPS)-induced acute lung injury in mice and the underlying mechanisms.

METHODS

Mice were injected with LPS (10 mg/kg, i.p.), then treated with TIIA (10 mg/kg, i.p.). Seven hours after LPS injection, the lungs were collected for histological study. Protein, LDH, TNF-α and IL-1β levels in bronchoalveolar lavage fluid (BALF) and myeloperoxidase (MPO) activity in lungs were measured. Cell apoptosis and Bcl-2, caspase-3, NF-κB and HIF-1α expression in lungs were assayed.

RESULTS

LPS caused marked histological changes in lungs, accompanied by significantly increased lung W/D ratio, protein content and LDH level in BALF, and Evans blue leakage. LPS markedly increased neutrophil infiltration in lungs and inflammatory cytokines in BALF. Furthermore, LPS induced cell apoptosis in lungs, as evidenced by increased TUNEL-positive cells, decreased Bcl-2 content and increased cleaved caspase-3 content. Moreover, LPS significantly increased the expression of NF-κB and HIF-1α in lungs. Treatment of LPS-injected mice with TIIA significantly alleviated these pathological changes in lungs.

CONCLUSION

TIIA alleviates LPS-induced acute lung injury in mice by suppressing inflammatory responses and apoptosis, which is mediated via inhibition of the NF-κB and HIF-1α pathways.

Endothelial Semaphorin 7A promotes inflammation in seawater aspiration-induced acute lung injury

Inflammation is involved in the pathogenesis of seawater aspiration-induced acute lung injury (ALI). Although several studies have shown that Semaphorin 7A (SEMA7A) promotes inflammation, there are limited reports regarding immunological function of SEMA7A in seawater aspiration-induced ALI. Therefore, we investigated the role of SEMA7A during seawater aspiration-induced ALI. Male Sprague–Dawley rats were underwent seawater instillation. Then, lung samples were collected at an indicated time for analysis. In addition, rat pulmonary microvascular endothelial cells (RPMVECs) were cultured and then stimulated with 25% seawater for indicated time point. After these treatments, cells samples were collected for analysis. In vivo, seawater instillation induced lung histopathologic changes, pro-inflammation cytokines release and increased expression of SEMA7A. In vitro, seawater stimulation led to pro-inflammation cytokine release, cytoskeleton remodeling and increased monolayer permeability in pulmonary microvascular endothelial cells. In addition, knockdown of hypoxia-inducible factor (HIF)-1α inhibited the seawater induced increase expression of SEMA7A. Meanwhile, knockdown of SEMA7A by specific siRNA inhibited the seawater induced aberrant inflammation, endothelial cytoskeleton remodeling and endothelial permeability. These results suggest that SEMA7A is critical in the development of lung inflammation and pulmonary edema in seawater aspiration-induced ALI, and may be a therapeutic target for this disease.

Tanshinon IIA injection accelerates tissue expansion by reducing the formation of the fibrous capsule

The tissue expansion technique has been applied to obtain new skin tissue to repair large defects in clinical practice. The implantation of tissue expander could initiate a host response to foreign body (FBR), which leads to fibrotic encapsulation around the expander and prolongs the period of tissue expansion. Tanshinon IIA (Tan IIA) has been shown to have anti-inflammation and immunoregulation effect. The rat tissue expansion model was used in this study to observe whether Tan IIA injection systematically could inhibit the FBR to reduce fibrous capsule formation and accelerate the process of tissue expansion. Forty-eight rats were randomly divided into the Tan IIA group and control group with 24 rats in each group. The expansion was conducted twice a week to maintain a capsule pressure of 60 mmHg. The expansion volume and expanded area were measured. The expanded tissue in the two groups was harvested, and histological staining was performed; proinflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β) and transforming growth factor-β (TGF-β) were examined. The expansion volume and the expanded area in the Tan IIA group were greater than that of the control group. The thickness of the fibrous capsule in the Tan IIA group was reduced with no influence on the normal skin regeneration. Decreased infiltration of macrophages, lower level of TNF-α, IL-6, IL-1β and TGF-β, less proliferating myofibroblasts and enhanced neovascularization were observed in the Tan IIA group. Our findings indicated that the Tan IIA injection reduced the formation of the fibrous capsule and accelerated the process of tissue expansion by inhibiting the FBR.

Bone marrow mesenchymal stem cells ameliorates seawater-exposure-induced acute lung injury by inhibiting autophagy in lung tissue

Seawater drowning can lead to acute lung injury (ALI). Several studies have shown that bone marrow mesenchymal stem cells (BMSC) treatment could attenuate ALI. However, the mechanisms underlying this phenomenon still remain elusive. Therefore, this study aimed to investigate whether BMSC treatment can ameliorate seawater-induced ALI and its underlying mechanisms in a rat model. In this study, arterial blood gas, lung weight coefficient, and TNF-α, and IL-8 in bronchoalveolar lavage fluid (BALF), as well as histopathology examination, were used to detect the lung injury of seawater exposure. Moreover, western blot and RT-PCR were used to explore autophagy in lung tissues. The results demonstrated that seawater exposure induced ALI including impaired arterial blood gas, pulmonary edema, histopathologic changes, and inflammatory response in lung tissues. What is more, these changes were partly ameliorated by BMSC treatment through inhibition of autophagy in lung tissues. The application of BMSC may be a potential effective treatment for seawater-induced ALI.

1α,25-dihydroxyvitamin D3 ameliorates seawater aspiration-induced acute lung injury via NF-κB and RhoA/Rho kinase pathways

INTRODUCTION

Inflammation and pulmonary edema are involved in the pathogenesis of seawater aspiration-induced acute lung injury (ALI). Although several studies have reported that 1α,25-Dihydroxyvitamin D3 (calcitriol) suppresses inflammation, it has not been confirmed to be effective in seawater aspiration-induced ALI. Thus, we investigated the effect of calcitriol on seawater aspiration-induced ALI and explored the probable mechanism.

METHODS

Male SD rats receiving different doses of calcitriol or not, underwent seawater instillation. Then lung samples were collected at 4 h for analysis. In addition, A549 cells and rat pulmonary microvascular endothelial cells (RPMVECs) were cultured with calcitriol or not and then stimulated with 25% seawater for 40 min. After these treatments, cells samples were collected for analysis.

RESULTS

Results from real-time PCR showed that seawater stimulation up-regulated the expression of vitamin D receptor in lung tissues, A549 cells and RPMVECs. Seawater stimulation also activates NF-κB and RhoA/Rho kinase pathways. However, we found that pretreatment with calcitriol significantly inhibited the activation of NF-κB and RhoA/Rho kinase pathways. Meanwhile, treatment of calcitriol also improved lung histopathologic changes, reduced inflammation, lung edema and vascular leakage.

CONCLUSIONS

These results demonstrated that NF-κB and RhoA/Rho kinase pathways are critical in the development of lung inflammation and pulmonary edema and that treatment with calcitriol could ameliorate seawater aspiration-induced ALI, which was probably through the inhibition of NF-κB and RhoA/Rho kinase pathways.

4-hydroxyphenylacetic acid attenuated inflammation and edema via suppressing HIF-1α in seawater aspiration-induced lung injury in rats

4-Hydroxyphenylacetic acid (4-HPA) is an active component of Chinese herb Aster tataricus which had been widely used in China for the treatment of pulmonary diseases. The aim of this study is to investigate the effect of 4-HPA on seawater aspiration-induced lung injury. Pulmonary inflammation and edema were assessed by enzyme-linked immunosorbent assay (ELISA), bronchoalveolar lavage fluid (BALF) white cell count, Evans blue dye analysis, wet to dry weight ratios, and histology study. Hypoxia-inducible factor-1α (HIF-1α) siRNA and permeability assay were used to study the effect of 4-HPA on the production of inflammatory cytokines and monolayer permeability in vitro. The results showed that 4-HPA reduced seawater instillation-induced mortality in rats. In lung tissues, 4-HPA attenuated hypoxia, inflammation, vascular leak, and edema, and decreased HIF-1α protein level. In primary rat alveolar epithelial cells (AEC), 4-HPA decreased hypertonicity- and hypoxia-induced HIF-1α protein levels through inhibiting the activations of protein translational regulators and via promoting HIF-1α protein degradation. In addition, 4-HPA lowered inflammatory cytokines levels through suppressing hypertonicity- and hypoxia-induced HIF-1α in NR8383 macrophages. Moreover, 4-HPA decreased monolayer permeability through suppressing hypertonicity and hypoxia-induced HIF-1α, which was mediated by inhibiting vascular endothelial growth factor (VEGF) in rat lung microvascular endothelial cell line (RLMVEC). In conclusion, 4-HPA attenuated inflammation and edema through suppressing hypertonic and hypoxic induction of HIF-1α in seawater aspiration-induced lung injury in rats.

Expression and function of aquaporin-1 in hyperoxia-exposed alveolar epithelial type II cells

The aim of the present study was to investigate water transport dysfunction in alveolar epithelial type II cells (AECII), which were exposed to hyperoxia, and to investigate the mechanism of pulmonary edema resulting from hyperoxic lung injury. The lung cells of newborn rats were isolated for primary cell culture and divided into control and experimental groups. The control and experimental group cells were placed into a normoxic incubator (oxygen volume fraction, 0.21) or hyperoxic incubator (oxygen volume fraction, 0.9), respectively. Twenty-four, 48 and 72 h after cell attachment, the gene transcription and protein expression levels of aquaporin-1 (AQP1) were detected via quantitative polymerase chain reaction and western blot analysis. Flow cytometry was conducted to detect the volume of the cells in the experimental and control groups. In the present study, it was identified that AQP1 expression and cell volume were greater in the experimental group when compared with the control group. Thus, hyperoxia may disturb the gene expression regulation of AQP1 in AECII, resulting in water transport dysfunction. This may be one of the mechanisms underlying pulmonary edema caused by hyperoxic lung injury.

Epigallocatechin-3-gallate ameliorates seawater aspiration-induced acute lung injury via regulating inflammatory cytokines and inhibiting JAK/STAT1 pathway in rats

Signal transducers and activators of transcriptions 1 (STAT1) play an important role in the inflammation process of acute lung injury (ALI). Epigallocatechin-3-gallate (EGCG) exhibits a specific and strong anti-STAT1 activity. Therefore, our study is to explore whether EGCG pretreatment can ameliorate seawater aspiration-induced ALI and its possible mechanisms. We detected the arterial partial pressure of oxygen, lung wet/dry weight ratios, protein content in bronchoalveolar lavage fluid, and the histopathologic and ultrastructure staining of the lung. The levels of IL-1, TNF-α, and IL-10 and the total and the phosphorylated protein level of STAT1, JAK1, and JAK2 were assessed in vitro and in vivo. The results showed that EGCG pretreatment significantly improved hypoxemia and histopathologic changes, alleviated pulmonary edema and lung vascular leak, reduced the production of TNF-α and IL-1, and increased the production of IL-10 in seawater aspiration-induced ALI rats. EGCG also prevented the seawater aspiration-induced increase of TNF-α and IL-1 and decrease of IL-10 in NR8383 cell line. Moreover, EGCG pretreatment reduced the total and the phosphorylated protein level of STAT1 in vivo and in vitro and reduced the phosphorylated protein level of JAK1 and JAK2. The present study demonstrates that EGCG ameliorates seawater aspiration-induced ALI via regulating inflammatory cytokines and inhibiting JAK/STAT1 pathway in rats.

TNF-α regulates natriuretic peptides and aquaporins in human bronchial epithelial cells BEAS-2B

Postoperative-fluid retention is a severe complication frequently reported in patients undergoing major surgical procedures. The complex network of molecules involved in such a severe surgery-induced condition remains poorly understood. Inflammation has been proposed among the various causes of fluid retention. Since TNF-α is one of the main proinflammatory cytokine initially released after major surgery, it is reasonable to assume its involvement in fluid overload. Here, we showed that TNF-α selectively regulates key molecules involved in fluids balance, such as natriuretic peptides (NPs) and aquaporins, in human bronchial epithelial cells BEAS-2B. In particular, we found that TNF-α induced a decrease of arial natriuretic peptide, natriuretic peptide receptor-1, aquaporin-1 and aquaporin-5 and an increase of brain natriuretic peptide with a different involvement of nuclear factor-κB and mitogen-activated protein kinases signaling pathway activation. Moreover, the observed changes in NPs expression, demonstrate inflammation as an additional cause of brain natriuretic peptide elevation, adding an important piece of information in the novel area of study regarding NPs and inflammation. Finally, we suggest that inflammation is one of the mechanisms of Aquaporin-1 and aquaporin-5 expression regulation. Therefore, in this exploratory study, we speculate that TNF-α might be involved in postoperative-fluid retention related to major surgery.

Participation of autophagy in acute lung injury induced by seawater

Seawater drowning can lead to acute lung injury (ALI). However, the molecular and cellular mechanisms underlying this phenomenon remain elusive. The overall aim of this study is to clarify the role of autophagy in seawater-induced ALI, by which we can further understand the molecular mechanism and develop new methods for prevention and treatment of seawater-induced ALI. In this study, electron microscopy, western blot analysis, and RT-PCR were used to detect autophagy in lung tissues. Moreover, arterial blood gas analysis, lung weight coefficient, TNF-α, IL-8 in bronchoalveolar fluid (BALF), histopathology were used to detect the lung injury of seawater exposure. An inhibitor of autophagy (3-Methyladenine, 3-MA) was injected intraperitoneally before seawater exposure to further explore the role of autophagy in ALI. Electron microscopy revealed increasing autophagosomes in alveolar epithelial cell in seawater group compared with the control. The transcription and expression levels (mRNA and protein levels) of the LC3 II significantly increased in lung tissue of seawater group compared with those in control group. Furthermore, the alterations of autophage were basically consistent with the changes in arterial blood gas, lung weight coefficient, TNF-α, IL-8 in BALF and morphologic findings. In addition, inhibition of autophagy by 3-MA partly ameliorated seawater-induced ALI, as indicated by reduced lung weight coefficient and TNF-α in BALF, as well as increased PaO2. In conclusion, seawater aspiration triggered autophagy, and autophagy may be a scathing factor responsible for ALI induced by seawater.

Pulmonary edema due to oral gavage in a toxicological study related to aquaporin-1, -4 and -5 expression

A one-time oral gavage can be enough to cause of alveologenic edema with higher expression of AQP-1 and -4 than that with repeated-dose oral gavage, which caused both profound perivascular edema and hydrostatic pressure edema, while AQP-5 was similarly expressed. The alteration of AQPs expression was probably related to alveolar fluid clearance across the alveolar and bronchiolar epithelium in different stages of lung injury. The results clarified the type of lung edema in acute and sub-chronic toxicity studies without treatment related effect of tested material. The pathogenesis of pulmonary edema due to oral gavage toxicological study is associated with the cellular immune response to the reflux materials. Mast cell and leukocyte accumulation may contribute to increase vascular permeability leading to permeability edema. The increase in alveolar septum epithelium, perivascular and peribronchial cuffing, accumulation alveolar lipid containing macrophage and medial hyperplasia of the pulmonary artery might have been caused to increase airway resistance, which resulted in hydrostatic pressure edema.

3,5,4'-tri-O-acetylresveratrol ameliorates seawater exposure-induced lung injury by upregulating connexin 43 expression in lung

The aim of the present study was to examine the effects of 3,5,4'-tri-O-acetylresveratrol on connexin 43 (Cx43) in acute lung injury (ALI) in rats induced by tracheal instillation of artificial seawater. Different doses (50, 150, and 450 mg/kg) of 3,5,4'-tri-O-acetylresveratrol were administered orally for 7 days before modeling. Four hours after seawater inhalation, histological changes, contents of TNF- α , IL-1 β and IL-10, and the expression of Cx43 in lungs were detected. Besides, the gap junction communication in A549 cells and human umbilical vein endothelial cells (HUVECs) challenged by seawater was also evaluated. Histological changes, increased contents of inflammatory factors, upregulation in gene level, and deregulation in protein level of Cx43 in lungs stimulated by seawater were observed. On the other hand, pretreatment with 3,5,4'-tri-O-acetylresveratrol significantly inhibited infiltration of inflammation, development of pulmonary edema, and contents of inflammatory mediators in lungs. Above all, 3,5,4'-tri-O-acetylresveratrol upregulated the expression of Cx43 in both gene and protein levels, and its intermediate metabolite, resveratrol, also enhanced the gap junction communication in the two cell lines. The results of the present study suggested that administration of 3,5,4'-tri-O-acetylresveratrol may be beneficial for treatment of inflammatorycellsin lung.