In vitro and in vivo protective potential of quercetin-3-glucuronide against lipopolysaccharide-induced pulmonary injury through dual activation of nuclear factor-erythroid 2 related factor 2 and autophagy

In vitro and in vivo models of lipopolysaccharide (LPS)-induced pulmonary injury, quercetin-3-glucuronide (Q3G) has been previously revealed the lung-protective potential via downregulation of inflammation, pyroptotic, and apoptotic cell death. However, the upstream signals mediating anti-pulmonary injury of Q3G have not yet been clarified. It has been reported that concerted dual activation of nuclear factor-erythroid 2 related factor 2 (Nrf2) and autophagy may prove to be a better treatment strategy in pulmonary injury. In this study, the effect of Q3G on antioxidant and autophagy were further investigated. Noncytotoxic doses of Q3G abolished the LPS-caused cell injury, and reactive oxygen species (ROS) generation with inductions in Nrf2-antioxidant signaling. Moreover, Q3G treatment repressed Nrf2 ubiquitination, and enhanced the association of Keap1 and p62 in the LPS-treated cells. Q3G also showed potential in inducing autophagy, as demonstrated by formation of acidic vesicular organelles (AVOs) and upregulation of autophagy factors. Next, the autolysosomes formation and cell survival were decreased by Q3G under pre-treatment with a lysosome inhibitor, chloroquine (CQ). Furthermore, mechanistic assays indicated that anti-pulmonary injury effects of Q3G might be mediated via Nrf2 signaling, as confirmed by the transfection of Nrf2 siRNA. Finally, Q3G significantly alleviated the development of pulmonary injury in vivo, which may result from inhibiting the LPS-induced lung dysfunction and edema. These findings emphasize a toxicological perspective, providing new insights into the mechanisms of Q3G's protective effects on LPS-induced pulmonary injury and highlighting its role in dual activating Nrf2 and autophagy pathways.

And its phenolic constituents ameliorate pulmonary injury and fibrosis in bleomycin-treated mice

ETHNOPHARMACOLOGICAL RELEVANCE

Pulmonary injury and fibrosis can be caused by various factors because of their inflammatory nature, both can lead to serious clinical consequences. Inula japonica Thunb. is used in traditional Chinese medicine for the treatment of lung diseases. However, the effect and mechanism of action of the essential oil of I. japonica (EOI) on pulmonary injury and fibrosis are not well understood.

AIM OF THE STUDY

To investigate the therapeutic effects of EOI on mice with bleomycin (BLM)-induced acute pulmonary injury and chronic fibrosis formation, as well as its potential mechanism.

MATERIALS AND METHODS

A short-term mouse model of pulmonary injury was established by intratracheal injection of BLM to investigate the anti-inflammatory effect of EOI, and a long-term model of pulmonary fibrosis was used to explore the anti-fibrosis effect of EOI. High-dose EOI (200 mg/kg) was administered intragastrically, and low-dose (50 mg/kg) was administered by intratracheal injection. Gas chromatography-mass spectrometry (GC-MS) was used to identify the ingredients in EOI, and high-performance liquid chromatography (HPLC) was performed for the preparation of EOI compounds. Western blot and real-time qPCR were used to verify the effects of EOI and its active composition on inflammation, oxidative stress and fibrosis signaling pathway.

RESULTS

Treatment with EOI significantly reduced the inflammation and oxidative stress by reducing the levels of inflammatory and oxidative cytokines such as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and malondialdehyde in BLM-treated mice with acute pulmonary injury. EOI treatment could also suppress the formation of fibrous tissue in mice with BLM-induced pulmonary fibrosis through inhibiting TGF-β/Smad and PI3K/Akt pathways. Chromatographic analysis and preparation suggested that fatty acid and phenol derivatives are present in EOI. Based on cellular inflammation and fibrosis models, the phenolic compounds in EOI can represent the anti-inflammatory and anti-fibrotic effects of EOI by regulating pro-inflammatory and pro-fibrotic cytokines such as NO, TNF-α, IL-6, TGF-β1, and α-SMA.

CONCLUSION

EOI ameliorated BLM-induced pulmonary injury and fibrosis in mice by inhibiting the inflammatory response and regulating the redox equilibrium, as well as by mediating TGFβ/Smad and PI3K/Akt, which suggested that EOI has potential to treat pulmonary diseases.

Lias overexpression alleviates pulmonary injury induced by fine particulate matter in mice

Oxidative stress and inflammation are mechanisms underlying toxicity induced by fine particulate matter (PM2.5). The antioxidant baseline of the human body modulates the intensity of oxidative stress in vivo. This present study aimed to evaluate the role of endogenous antioxidants in alleviating PM2.5-induced pulmonary injury using a novel mouse model (LiasH/H) with an endogenous antioxidant capacity of approximately 150% of its wild-type counterpart (Lias+/+). LiasH/H and wild-type (Lias+/+) mice were randomly divided into control and PM2.5 exposure groups (n = 10), respectively. Mice in the PM2.5 group and the control group were intratracheally instilled with PM2.5 suspension and saline, respectively, once a day for 7 consecutive days. The metal content, major pathological changes in the lung, and levels of oxidative stress and inflammation biomarkers were examined. The results showed that PM2.5 exposure induced oxidative stress in mice. Overexpression of the Lias gene significantly increased the antioxidant levels and decreased inflammatory responses induced by PM2.5. Further study found that LiasH/H mice exerted their antioxidant function by activating the ROS-p38MAPK-Nrf2 pathway. Therefore, the novel mouse model is useful for the elucidation of the mechanisms of pulmonary injury induced by PM2.5.

Intratracheally administered iron oxide nanoparticles induced murine lung inflammation depending on T cells and B cells

Iron oxide nanoparticles (Fe₂O₃ NPs), produced in track traffic system and a wide range of industrial production, poses a great threat to human health. However, there is little research about the mechanism of Fe₂O₃ NPs toxicity on respiratory system. Rag1^-/- mice which lack functional T and B cells were intratracheally challenged with Fe₂O₃ NPs, and interleukin (IL)-33 as an activator of group 2 innate lymphoid cells (ILC2s) to observe ILC2s changes. The lung inflammatory response to Fe₂O₃ NPs was alleviated in Rag1^-/- mice compared with wild type (WT) mice. Infiltration of inflammatory cells and collagen deposition in tissue, leukocyte numbers (neutrophils, macrophages and lymphocytes), cytokine levels, such as IL-6, IL-13 and thymic stromal lymphopoietin (TSLP), and expression of Toll-like receptor (TLR)2, TLR4, and downstream myeloid differentiation factor (MyD)88, nuclear factor (NF)-κB and tumor necrosis factor (TNF)-α were decreased in lungs. Fe₂O₃ NPs markedly elevated ILC2s compared with the control, but ILC2s numbers were much lower compared with IL-33 in both WT and Rag1^-/- mice. Furthermore, ILC2s amounts were strongly greater in Rag1^-/- mice than WT mice. Our results suggested that Fe₂O₃ NPs induced sub-chronic pulmonary inflammation, which is majorly dependent on T cells and B cells rather than ILC2s.

Lung ultrasonography versus chest CT for assessing peripheric pulmonary lesions in hemorrhagic fever with renal syndrome: a prospective comparative study in China

OBJECTIVES

To compare the performances of lung ultrasonography (LUS) versus chest CT for assessing peripheric pulmonary lesions in hemorrhagic fever with renal syndrome (HFRS).

METHODS

Paired LUS and chest CT scan were prospectively performed and compared when in diagnosing five pathologies including region with alveolar-interstitial pattern (RAIP), alveolar-interstitial syndrome (AIS), lung consolidation, pleural effusion (PE), and pericardial effusion, in each patient with HFRS.

RESULTS

Forty-four patients (aged 39.9 ± 15.0 years, 35 males) were included, from which 68 paired LUS and chest CT imaging data of 816 lung regions were obtained and analyzed. Compared with chest CT, LUS showed high sensitivity (92.19-100%) and negative predictive value (95.9-100%), but relatively low specificity (39.47-97.21%) and positive predictive value (37.5-76.47%) for diagnosing the above pathologies. McNemer's test showed LUS detected more positive findings than chest CT (all p ≤ 0.002). There was a strong correlation between LUS and chest CT scores (r_s = 0.7141, p < 0.0001) and both scores correlated with the disease severity, hospital days, and partial laboratory profiles in HFRS patients.

CONCLUSIONS

LUS was comparable with chest CT for diagnosing peripheric pulmonary lesions and clinical assessment in patients with HFRS. Given the high sensitivity and negative predictive value compared with chest CT, LUS can be used as an excellent rule-out tool in HFRS, while its use in rule-in still requires more evidence. Considering the obvious advantages of LUS being a bedside, less expansive, and non-radiating exam, future multi-center randomized LUS versus chest CT studies may help to guide the preferred method.

KEY POINTS

• LUS could detect more positive findings than chest CT in assessing peripheric pulmonary lesions in patients with hemorrhagic fever with renal syndrome (HFRS). • Compared with chest CT, LUS showed high sensitivity but relatively low specificity when diagnosing the peripheric pulmonary lesions caused by HFRS. • Both LUS and chest CT scores correlated with the disease severity, hospital days, and partial laboratory profiles in HFRS.

Pulmonary inflammation, oxidative stress, and fibrosis in a mouse model of cholestasis: the potential protective properties of the dipeptide carnosine

Cholestasis is a clinical complication that primarily influences the liver. However, it is well known that many other organs could be affected by cholestasis. Lung tissue is a major organ influenced during cholestasis. Cholestasis-induced lung injury could induce severe complications such as respiratory distress, serious pulmonary infections, and tissue fibrosis. Unfortunately, there is no specific pharmacological intervention against this complication. Several studies revealed that oxidative stress and inflammatory response play a role in cholestasis-induced lung injury. Carnosine (CARN) is a dipeptide found at high concentrations in different tissues of humans. CARN's antioxidant and antiinflammatory properties are repeatedly mentioned in various experimental models. This study aimed to assess the role of CARN on cholestasis-induced lung injury. Rats underwent bile duct ligation (BDL) to induce cholestasis. Broncho-alveolar lavage fluid (BALF) levels of inflammatory cells, pro-inflammatory cytokines, and immunoglobulin were monitored at scheduled intervals (7, 14, and 28 days after BDL). Moreover, lung tissue histopathological alterations and biomarkers of oxidative stress were evaluated. A significant increase in BALF inflammatory cells, TNF-α, IL-1β, IL-6, and immunoglobulin-G (IgG) was detected in the BALF of BDL rats. Moreover, lung tissue histopathological changes, collagen deposition, increased TGF-β, and elevated levels of oxidative stress biomarkers were evident in cholestatic animals. It was found that CARN (100 and 500 mg/kg, i.p.) significantly alleviated lung oxidative stress biomarkers, inflammatory response, tissue fibrosis, and histopathological alterations. These data indicate the potential protective properties of CARN in the management of cholestasis-induced pulmonary damage. The effects of CARN on inflammatory response and oxidative stress biomarkers seems to play a crucial role in its protective properties in the lung of cholestatic animals.

Taurine mitigates the development of pulmonary inflammation, oxidative stress, and histopathological alterations in a rat model of bile duct ligation

Lung injury is a significant complication associated with cholestasis/cirrhosis. This problem significantly increases the risk of cirrhosis-related morbidity and mortality. Hence, finding effective therapeutic options in this field has significant clinical value. Severe inflammation and oxidative stress are involved in the mechanism of cirrhosis-induced lung injury. Taurine (TAU) is an abundant amino acid with substantial anti-inflammatory and antioxidative properties. The current study was designed to evaluate the role of TAU in cholestasis-related lung injury. For this purpose, bile duct ligated (BDL) rats were treated with TAU (0.5 and 1% w: v in drinking water). Significant increases in the broncho-alveolar lavage fluid (BALF) level of inflammatory cells (lymphocytes, neutrophils, basophils, monocytes, and eosinophils), increased IgG, and TNF-α were detected in the BDL animals (14 and 28 days after the BDL surgery). Alveolar congestion, hemorrhage, and fibrosis were the dominant pulmonary histopathological changes in the BDL group. Significant increases in the pulmonary tissue biomarkers of oxidative stress, including reactive oxygen species formation, lipid peroxidation, increased oxidized glutathione levels, and decreased reduced glutathione, were also detected in the BDL rats. Moreover, significant myeloperoxidase activity and nitric oxide levels were seen in the lung of BDL rats. It was found that TAU significantly blunted inflammation, alleviated oxidative stress, and mitigated lung histopathological changes in BDL animals. These data suggest TAU as a potential protective agent against cholestasis/cirrhosis-related lung injury.

Angiotensin converting enzyme (ACE) inhibitors as radiation countermeasures for long-duration space flights

Angiotensin converting enzyme (ACE) inhibitors are effective countermeasures to chronic radiation injuries in rodent models, and there is evidence for similar effects in humans. In rodent models ACE inhibitors are effective mitigators of radiation injury to kidney, lung, central nervous system (CNS) and skin, even when started weeks after irradiation. In humans, the best data for their efficacy as radiation countermeasures comes from retrospective studies of injuries in radiotherapy patients. We propose that ACE inhibitors, at doses approved for human use for other indications, could be used to reduce the risk of chronic radiation injuries from deep-space exploration. Because of the potential interaction of ACE inhibitors and microgravity (due to effects of ACE inhibitors on fluid balance) use might be restricted to post-exposure when/if radiation exposures reached a danger level. A major unresolved issue for this approach is the sparse evidence for the efficacy of ACE inhibitors after low-dose-rate exposure and/or for high-LET radiations (as would occur on long-duration space flights). A second issue is that the lack of a clear mechanism of action of the ACE inhibitors as mitigators makes obtaining an appropriate label under the Food and Drug Administration Animal Rule difficult.

Multi-omics analysis unravels dysregulated lysosomal function and lipid metabolism involved in sub-chronic particulate matter-induced pulmonary injury

Particulate matter (PM) is a huge environmental threat and is of major public concern. Oxidative stress and systemic inflammation are known factors that contribute to PM- related damage; however, a systematic understanding of the deleterious pulmonary effects of PM using multi-omics analysis is lacking. In this study, we performed transcriptomic, proteomic, and metabolomic analyses in a mouse model exposed to PM for three months to identify molecular changes in lung tissues. We identified 1690 genes, 326 proteins, and 67 metabolites exhibiting significant differences between PM-challenged and control mice (p < 0.05). Differentially expressed genes and proteins regulated in PM-challenged mice were involved in lipid metabolism and in the immune and inflammatory response processes. Moreover, a comprehensive analysis of transcript, protein, and metabolite datasets revealed that the genes, proteins, and metabolites in the PM-treated group were involved in lysosomal function and lipid metabolism. Specifically, Cathepsin D (Ctsd), Ferritin light chain (Ftl), Lactotransferrin (Ltf), Lipocalin 2 (Lcn2), and Prosaposin (Psap) were major proteins/genes associated with PM-induced pulmonary damage, while two lipid molecules PC (18:1(11Z)/16:0) and PA (16:0/18:1(11Z)) were major metabolites related to PM-induced pulmonary injury. In summary, lipid metabolism might be used as successful precautions and therapeutic targets in PM-induced pulmonary injury to maintain the stability of cellular lysosomal function.

Paeoniflorin ameliorates airway inflammation and immune response in ovalbumin induced asthmatic mice: From oxidative stress to autophagy

BACKGROUND

Asthma characterized by airway remodeling is a multiple pulmonary disease, which is associated with various physiological processes including inflammation reaction, immune response, oxidative stress and autophagy.

PURPOSE

This study aimed to investigate whether these processes are modulated by the total glucosides of Paeonia lactiflora Pall (TGP), and its active compound paeoniflorin (PF) with anti-inflammatory and immune-regulatory effects could alleviate ovalbumin (OVA)-induced mouse asthma.

METHODS

In vivo, models of mouse asthma were established by intraperitoneally with a mixture of OVA and aluminum hydroxide, plus a single nasal injected with OVA to female C57BL/6 mice. The results were observed with PET imaging, TEM, RT-PCR, western blotting. In vitro, CD4⁺ T cells were isolated and detected with flow cytometry.

RESULTS

TGP, either in its crude or processed form, and PF effectively ameliorated lung injury in mice induced by OVA, regulated immune/inflammatory response by inhibiting the release of pro-inflammatory cytokines, thereby decreasing Th2 cell proportion, inhibited oxidative stress by recovering mitochondrial membrane potential and regulating metabolic activity in dose-dependent manner. Moreover, PF could inhibit autophagy by regulating mitochondrial function. In addition, the therapeutic effects of TGP and PF on pulmonary injury in asthmatic mice were not affected by processing.

CONCLUSION

PF may be a valuable agent in ameliorating inflammation and immune response in asthmatic mice, and the possible mechanism involved in this response rang may from oxidative stress to autophagy.

Exploring the potential neurotoxicity of vaping vitamin E or vitamin E acetate

Serious adverse health effects have been reported with the use of vaping products, including neurologic disorders and e-cigarette or vaping product use-associated lung injury (EVALI). Vitamin E acetate, likely added as a diluent to cannabis-containing products, was linked to EVALI. Literature searches were performed on vitamin E and vitamin E acetate-associated neurotoxicity. Blood brain barrier (BBB) penetration potential of vitamin E and vitamin E acetate were evaluated using cheminformatic techniques. Review of the literature showed that the neurotoxic potential of inhalation exposures to these compounds in humans is unknown. Physico-chemical properties demonstrate these compounds are lipophilic, and molecular weights indicate vitamin E and vitamin E acetate have the potential for BBB permeability. Computational models also predict both compounds may cross the BBB via passive diffusion. Based on literature search, no experimental nonclinical studies and clinical information on the neurotoxic potential of vitamin E via inhalation. Neurotoxic effects from pyrolysis by-product, phenyl acetate, structurally analogous to vitamin E acetate, suggests vitamin E acetate has potential for central nervous system (CNS) impairment. Cheminformatic model predictions provide a theoretical basis for potential CNS permeability of these inhaled dietary ingredients suggesting prioritization to evaluate for potential hazard to the CNS.

Trace endotoxin in reclaimed water is only one of the risk sources in subchronic inhalation exposure

Pulmonary injury and inflammation have been detected in cases of subchronic inhalation exposure to reclaimed water, but the mechanism remains unclear. Endotoxin has been verified as the key risk factor in acute inhalation exposure through the TLR4 (Toll-like receptor 4) signalling pathway. In long-term exposure, endotoxin may also be a risk factor in reclaimed water, but the contribution of other health risk factors should not be underestimated. Wild-type C57BL/6J and TLR4-signalling-pathway-defective mice were used in this study to assess the risk of subchronic inhalation exposure to reclaimed water. Two types of reclaimed water, i.e., secondary effluent and MBR (membrane bioreactor) effluent, were found to induce pulmonary injury and inflammation in the wild-type mice and Tlr4^-/- mutants. However, when both mice were exposed to the same concentrations of pure endotoxin in reclaimed water, only the wild-type mice that were treated with high-dose endotoxin showed pulmonary injury. In summary, non-TLR4 signalling pathways are related to lung inflammation caused by long-term exposure to reclaimed water. It is highly possible that pollutants in addition to endotoxin in the reclaimed water can induce chronic inflammation in the lung.

Tidal volume measurements via transthoracic impedance waveform characteristics: The effect of age, body mass index and gender. A single centre interventional study

BACKGROUND AND AIM

Measuring tidal volumes (TV) during bag-valve ventilation is challenging in the clinical setting. The ventilation waveform amplitude of the transthoracic impedance (TTI-amplitude) correlates well with TV for an individual, but poorer between patients. We hypothesized that TV to TTI-amplitude relations could be improved when adjusted for morphometric variables like body mass index (BMI), gender or age, and that TTI-amplitude cut-offs for ventilations with adequate TV (>400ml) could be established.

MATERIALS AND METHODS

Twenty-one consenting adults (9 female, and 9 overall overweight) during positive pressure ventilation in anaesthesia before scheduled surgery were included. Seventeen ventilator modes were used (⩾ five breaths per mode) to adjust different TVs (150-800 ml), ventilation frequencies (10-30 min^-1) and insufflation times (0.5-3.5 s). TTI from the defibrillation pads was filtered to obtain ventilation TTI-amplitudes. Linear regression models were fitted between target and explanatory variables, and compared (coefficient of determination, R²).

RESULTS

The TV to TTI-amplitude slope was 1.39 Ω/l (R²=0.52), with significant differences (p<0.05) between male/female (1.04 Ω/l vs 1.84 Ω/l) and normal/overweight subjects (1.65 Ω/l vs 1.04 Ω/l). The median (interquartile range) TTI-amplitude cut-off for adequate TV was 0.51 Ω(0.14-1.20) with significant differences between males and females (0.58 Ω/0.39 Ω), and normal and overweight subjects (0.52 Ω/0.46 Ω). The TV to TTI-amplitude model improved (R²=0.66) when BMI, age and gender were included.

CONCLUSIONS

TTI-amplitude to TV relations were established and cut-offs for ventilations with adequate TV determined. Patient morphometric variables related to gender, age and BMI explain part of the variability in the measurements.

Protective and anti-inflammatory effect of selenium nano-particles against bleomycin-induced pulmonary injury in male rats

Pulmonary fibrosis (PF) is an interstitial lung disease, in which the exact pathologic mechanisms are not fully understood. Drug trials for the treatment of PF have shown disappointing results and controversial. Recently, selenium nanoparticles (SeNPs) have received great attention for potential use in treatments, due to high bioactivity features and lower toxicity. This study evaluated the protective effect of SeNPs against pulmonary injury induced by bleomycin (single dose, 4 mg/kg, intratracheal) in male rats in early and late phases of the disease. The rats were treated with SeNPs by intraperitoneal injection (0.5 mg SeNP/kg) for five consecutive days in the early phase (a day after injection of bleomycin) and late phase (a week after injection of bleomycin). The results showed that injection of SeNPs in the early phase improved the degree of alveolitis and inflammation and lung structure damage. Also, led to significant decreases in density of transforming growth factor- β1 (TGF-β1) in the lung and tumor necrosis factor-α (TNF-α) levels in the serum and lung homogenates compared with bleomycin-administrated group. Notably, treatment with the SeNP during the late phase did not show any ameliorative effects. Thus, the data suggest that SeNP has a protective effect against bleomycin-induced pulmonary injury in rats in the early phase of the disease. This might mean that SeNPs may be a new therapeutic agent for the improvement of this disease in the early phases.

Aggravated pulmonary injury after subarachnoid hemorrhage in PDGF-Bret/ret mice

Background

Recent advances in surgical and neuroprotective strategies could effectively manage the pathophysiological progression of subarachnoid hemorrhage (SAH). However, pulmonary dysfunction frequently occurs in SAH patients with an increased risk of unsatisfactory outcomes. Based on the similar microvascular structures in the blood-air barrier and blood-brain barrier and possible brain-lung crosstalks, we believe that pericytes may be involved in both neurological and pulmonary dysfunction after SAH.

Methods

In our experiments, platelet-derived growth factor B (PDGF-B) retention motif knockout (PDGF-B^ret/ret) mice and adeno-associated virus PDGF-B were employed to show the involvement of pericyte deficiency and PDGF-B expression. Neurological score, SAH grade, hematoxylin-eosin staining, and PaO2/FiO2 ratio analysis were performed to evaluate the neurological deficits and pulmonary functions in endovascular perforation SAH models at 24 h after surgery, as well as western blotting and immunofluorescence staining for underlying molecular expressions.

Results

We found that neonatal PDGF-B^ret/ret mice exhibited pulmonary atelectasis 12 h after birth. Further investigation showed a decrease in PaO₂/FiO₂ and lung-specific surfactant proteins in adult PDGF-B^ret/ret mice. These dysfunctions were much worse than those in wild-type mice at 24 h after SAH. PDGF-B overexpression alleviated pulmonary dysfunction after SAH.

Conclusions

These results suggested pulmonary dysfunction after SAH and the pivotal role of PDGF-B signaling for the pathophysiological process and future therapeutic targets of pulmonary injury treatment after SAH. Further studies are needed for pathophysiological investigations and translational studies on pulmonary injuries after SAH.

Caloric restriction attenuates C57BL/6 J mouse lung injury and extra-pulmonary toxicity induced by real ambient particulate matter exposure

Background

Caloric restriction (CR) is known to improve health and extend lifespan in human beings. The effects of CR on adverse health outcomes in response to particulate matter (PM) exposure and the underlying mechanisms have yet to be defined.

Results

Male C57BL/6 J mice were fed with a CR diet or ad libitum (AL) and exposed to PM for 4 weeks in a real-ambient PM exposure system located at Shijiazhuang, China, with a daily mean concentration (95.77 μg/m³) of PM_2.5. Compared to AL-fed mice, CR-fed mice showed attenuated PM-induced pulmonary injury and extra-pulmonary toxicity characterized by reduction in oxidative stress, DNA damage and inflammation. RNA sequence analysis revealed that several pulmonary pathways that were involved in production of reactive oxygen species (ROS), cytokine production, and inflammatory cell activation were inactivated, while those mediating antioxidant generation and DNA repair were activated in CR-fed mice upon PM exposure. In addition, transcriptome analysis of murine livers revealed that CR led to induction of xenobiotic metabolism and detoxification pathways, corroborated by increased levels of urinary metabolites of polycyclic aromatic hydrocarbons (PAHs) and decreased cytotoxicity measured in an ex vivo assay.

Conclusion

These novel results demonstrate, for the first time, that CR in mice confers resistance against pulmonary injuries and extra-pulmonary toxicity induced by PM exposure. CR led to activation of xenobiotic metabolism and enhanced detoxification of PM-bound chemicals. These findings provide evidence that dietary intervention may afford therapeutic means to reduce the health risk associated with PM exposure.

Diosmin ameliorative effects on oxidative stress and fibrosis in paraquat-induced lung injury in mice

Paraquat (PQ) induces pulmonary fibrosis, a progressive lung disorder resulting in severe respiratory failure and death. Increased oxidative stress, inflammatory reactions, and multiple fibrotic lesions are major features of PQ-induced lung injury. Diosmin (Dio) is a safe drug that is available for clinical use for vascular disorders. Dio exhibits antioxidant, anti-inflammatory, and antifibrotic activities. Accordingly, the aim of this study was to evaluate the protective effect of diosmin on PQ-induced lung injury in mice and the underlying mechanisms involved. Lung injury was induced by PQ (30 mg/kg, intraperitoneally) in NMRI albino mice and Dio (50 and 100 mg/kg, gavage) was administrated 3 days before PQ and continued for 10 or 24 days. After euthanizing the mice, the biochemical and histopathological markers of lung tissue were determined. PQ significantly increased oxidative stress, inflammatory, and fibrotic markers. PQ increased the level of malonedaldehyde (MDA) and hydroxyproline (HYP) and decreased the level of glutathione (GSH) and catalase activity in the lung. Dio (50 and 100 mg/kg) significantly increased GSH levels and catalase activity and decreased HYP content and MDA levels. In addition, Dio reduced histopathological injuries in hematoxylin and eosin-stained and Masson's trichrome-stained sections. These findings suggest that Dio has protective effects against PQ-induced lung injury, which may be due to its antioxidant, anti-inflammatory, and antifibrotic effects.

High-voltage electrocution-induced pulmonary injury and cerebellar hemorrhage with fractures in atlas

Background

Electrocution is a common cause of mild to severe multisystem injuries leading to high rate of mortality and morbidity. Low to high-voltage injury may be clinically manifested from a simple unpleasant sensation to multiple soft tissue injury which may cause instant death. The severity of injury depends on intensity of the electrical current, voltage of the source, resistance in the victims' body and the duration of the contact.

Case presentation

A 20-year-old young male experienced with an accidental high-voltage electrocution injury from a blasted electrical transformer while passing across the road. He lost his consciousness and immediately hospitalized. Bilateral pulmonary infiltrates and right cerebellar hemorrhage with fractures in anterior and posterior arch of the first cervical vertebrae (C1) were diagnosed, and there was no history of electrical burn. He stayed in hospital for three days and completely treated with initial oxygen supplementation and immobilization of his head and neck with a Philadelphia collar for 6 weeks. Electrocution is a serious public health concern and reported worldwide with few fatal ending. Accidental high-voltage electrocution injury is a serious type of unfortunate accidental injuries which in most of times, ends with immediate or delayed sequelae or even death. In this case, the victim with high-voltage-associated electrical injuries in his lungs and brain was completely recovered because of early hospitalization.

Conclusions

Electrocution injury is an accidental event with high mortality and morbidity rate. Mild to severe electrical current-induced injuries including burn can be treated successfully in most of the cases, but early hospitalization is highly required.

Toxicological assessment of dust from sanding micronized copper-treated lumber in vivo

Micronized copper azole (MCA) is a lumber treatment improve longevity. In this study, the in vivo response to PM_2.5 sanding dust generated from MCA-treated lumber was compared to that of untreated yellow pine (UYP) or soluble copper azole-treated (CA-C) lumber to determine if the MCA was more bioactive than CA-C. Mice were exposed to doses (28, 140, or 280 μg/mouse) of UYP, MCA, or CA-C sanding dust using oropharyngeal aspiration. Bronchoalveolar lavage fluid (BALF) lactate dehydrogenase activity was increased at 1 day post-exposure to 280 μg/mouse of MCA and CA-C compared to UYP. BALF polymorphonuclear cells were increased by MCA and CA-C. There were increases in BALF cytokines in MCA and CA-C-exposed groups at 1 day post-exposure. Lung histopathology indicated inflammation with infiltration of neutrophils and macrophages. Pulmonary responses were more severe in MCA and CA-C-exposed groups at 1 day post-exposure. MCA caused more severe inflammatory responses than CA-C at 1 day post-exposure. These findings suggest that the MCA and CA-C sanding dusts are more bioactive than the UYP sanding dust, and, moreover, the MCA sanding dust is more bioactive in comparison to the CA-C sanding dust. No chronic toxic effects were observed among all observed sanding dusts.

Effects of Breath-Hold Deep Diving on the Pulmonary System

This short review focuses on pulmonary injury in breath-hold (BH) divers. When practicing their extreme leisure sport, they are exposed to increased pressure on pulmonary gas volumes, hypoxia, and increased partial gas pressures. Increasing ambient pressures do present a serious problem to BH deep divers, because the semi-rigid thorax prevents the deformation required by the Boyle-Mariotte law. As a result, a negative-pressure barotrauma (lung squeeze) with acute hemoptysis is not uncommon. Respiratory maneuvers such as glossopharyngeal insufflation (GI) and glossopharyngeal exsufflation (GE) are practiced to prevent lung squeeze and to permit equalizing the paranasal sinuses and the middle ear. GI not only impairs venous return, thereby provoking hypotension and even fainting, but also produces intrathoracic pressures likely to induce pulmonary barotrauma that is speculated to induce long-term injury. GE, in turn, further increases the already negative intrapulmonary pressure, thereby favoring alveolar collapse (atelectasis). Finally, hypoxia seemingly not only induces brain injury but initiates the opening of intrapulmonary shunts. These pathways are large enough to permit transpulmonary passage of venous N2 bubbles, making stroke-like phenomena in deep BH divers possible.

Rapamycin alleviated pulmonary injury induced by fat embolism syndrome in rats

Fat embolism syndrome (FES) is a serious complication after trauma, surgery and fat emulsion input and can lead to serious pulmonary injury. Autophagy controls the cell survival and homeostasis by removing the mis-folded proteins and damaged organelles as well as intracellular pathogens through a lysosomal degradation pathway. Increasing research documented that autophagy was wildly involved in variety of human diseases and had huge therapeutic potential. However, the role and mechanism of autophagy in FES remains largely unknown. The rat model of FES was established by tail vein injection with fat and was assessed by Wet-to-Dry (W/D) ratio analysis, hematoxylin-eosin (HE) analysis, staining Oil red staining analysis and qPCR analysis. Western blots were employed to detect the expression of autophagy markers. The changes of pulmonary injury were observed after premedication of rapamycin (an autophagy activator). The alveolar structural damage, red free fat substances in the blood vessels of lung, increased the lung ratio, and the up-regulated MPO expression and activity were showed in the FES models. The expressions of autophagy markers were decreased and meanwhile, apoptosis markers were increased in the FES model. Rapamycin restored the expression of autophagy markers and inhibited the apoptosis and further, resulting in the improvement of the pulmonary injury. Thus, our study demonstrated that autophagy was inhibited and apoptosis was promoted in FES and further Rapamycin alleviated the pulmonary damage in FES via restoring the autophagy and inhibiting the apoptosis.

Effect of ulinastatin on interleukins and pulmonary function in bypass patients: a meta-analysis of randomized controlled trials

BACKGROUND

Our aim was to evaluate the effect of urinary trypsin inhibitors (UTI) on interleukin, tumor necrosis factor-α (TNF-α), and polymorphonuclear neutrophil elastase (PMNE) levels as well as on pulmonary function in patients undergoing cardiopulmonary bypass.

MATERIALS AND METHODS

We searched the following databases for relevant studies: PubMed, Medline (Ovid SP), Cochrane Library, Wanfang Data, China Biology Medicine Database, Chinese Periodical Database, China Knowledge Resource Integrated Database, and Chinese Clinical Trial Registry. Two investigators independently collected the data and assessed the quality of each study. RevMan 5.3 was used for the meta-analysis.

RESULTS

In total, 15 randomized controlled trials (646 patients) met the inclusion criteria. There was a significant decrease in TNF-α, interleukin-6 (IL-6), IL-8, and PMNE levels at 6 h and 24 h after UTI treatment and an increase in IL-10 levels; additionally, there was a decrease in respiratory index and an improvement in the oxygenation index. Nevertheless, UTI treatment did not affect the length of intensive care unit stay, alveolar-arterial oxygen partial pressure difference, adverse lung events, or hospital mortality. Because of the high heterogeneity of the included trials, the results should be assessed carefully.

CONCLUSION

UTI treatment can suppress proinflammatory cytokine elevation and upregulate the release of anti-inflammatory mediators, thereby reducing pulmonary injury and improving pulmonary function after cardiopulmonary bypass.

A proteomic study of the pulmonary injury induced by microcystin-LR in mice

MCLR has been shown to act as potent hepatotoxin, and recent studies showed that MCs can accumulate in lung tissue and exert adverse effects. However, the exact mechanism still remain unclear. The present study mainly focuses on the impairments of respiratory system after MCLR exposure in mice. After intratracheal instillation with MCLR (0, 10 and 25 μg/kg bw), histological change was examined in MCLR exposure groups. Results indicated that exposure of MCLR led to serious histopathology alteration and apoptosis in lung of mice. To further our understanding of the toxic effects of MCLR on the lung, we employed a proteomic method to search the mechanisms behind MCLR-induced pulmonary injury. In total, 38 proteins were identified to be significantly altered after MCLR exposure. These proteins involved in inflammatory response, apoptosis, cytoskeleton, and energetic metabolism, suggesting MCLR exerts complex toxic effects contributing to pulmonary injury. Furthermore, MCLR also induced pulmonary inflammation, as manifested by up-regulating the protein levels of interleukin-1β (IL-1β) and p65 subunit. Our results indicated that MCLR exerts lung injury mainly by generating inflammation and apoptosis.

Reduced serum club cell protein as a pulmonary damage marker for chronic fine particulate matter exposure in Chinese population

BACKGROUND

Exposure to fine particulate matter (PM_2.5) pollution is associated with increased morbidity and mortality from respiratory diseases. However, few population-based studies have been conducted to assess the alterations in circulating pulmonary proteins due to long-term PM_2.5 exposure.

METHODS

We designed a two-stage study. In the first stage (training set), we assessed the associations between PM_2.5 exposure and levels of pulmonary damage markers (CC16, SP-A and SP-D) and lung function in a coke oven emission (COE) cohort with 558 coke plant workers and 210 controls. In the second stage (validation set), significant initial findings were validated by an independent diesel engine exhaust (DEE) cohort with 50 DEE exposed workers and 50 controls.

RESULTS

Serum CC16 levels decreased in a dose response manner in association with both external and internal PM_2.5 exposures in the two cohorts. In the training set, serum CC16 levels decreased with increasing duration of occupational PM_2.5 exposure history. An interquartile range (IQR) (122.0μg/m³) increase in PM_2.5 was associated with a 5.76% decrease in serum CC16 levels, whereas an IQR (1.06μmol/mol creatinine) increase in urinary 1-hydroxypyrene (1-OHP) concentration was associated with a 5.36% decrease in serum CC16 levels in the COE cohort. In the validation set, the concentration of serum CC16 in the PM_2.5 exposed group was 22.42% lower than that of the controls and an IQR (1.24μmol/mol creatinine) increase in urinary 1-OHP concentration was associated with a 12.24% decrease in serum CC16 levels in the DEE cohort.

CONCLUSIONS

Serum CC16 levels may be a sensitive marker for pulmonary damage in populations with high PM_2.5 exposure.

Regulatory role of miR-18a to CCN2 by TGF-β1 signaling pathway in pulmonary injury induced by nano-SiO2

This research is designed to investigate the regulatory effect of miR-18a to the target gene connective tissue growth factor (CTGF, or CCN2), by participating in TGF-β1 signaling pathway and explore the pathogenic mechanism of miR-18a in pulmonary injury induced by nano-SiO₂ based on our early study. miR-18a and expression of TGF-β1 in Chinese hamster lung (CHL) fibroblasts cells stimulated by supernatants of NR8383 cells exposed to 40 μg/ml nano-SiO₂ for 24 h demonstrated 1.58 ± 0.22-fold and 1096.00 ± 2.60 pg/ml increase compared with blank control group analyzed by real-time quantitative PCR (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA), respectively. Expression increase of miR-18a and reduction of CCN2 mRNA expression levels and protein gray value ratio detected by Western blotting in CHL cells transfect miR-18a mimics for 48 h. The reverse of CHL cell transfection miR-18a inhibit is also true. The result of miR-18a and CCN2 binding sites tested by luciferase reporter gene assay shows that the report relative fluorescence value of miR-18a mimics wild type on CCN2 is 0.50 ± 0.02 with the control of mimics NC and mutant relative fluorescence report value 0.86 ± 0.04 (P < 0.05). Expression levels of miR-18a, CCN2 mRNA, and protein gray value ratio decreased in CHL cells treated by TGF-β1, respectively, and vice versa treated by TGF-β1corepressor. The results suggest that CCN2 is the target gene regulated by miR-18a and miR-18a participates in TGF-β1 signaling pathway by regulating the expression of CCN2 negatively through CCN2 3'UTR site, and thus may be involved in the development process of pulmonary injury.

Metabolomics analysis reveals that benzo[a]pyrene, a component of PM2.5, promotes pulmonary injury by modifying lipid metabolism in a phospholipase A2-dependent manner in vivo and in vitro

Particulate matter with an aerodynamic diameter less than 2.5 μM (PM_2.5) is one of the major environmental pollutants in China. In this study, we carried out a metabolomics profile study on PM_2.5-induced inflammation. PM_2.5 from Beijing, China, was collected and given to rats through intra-tracheal instillation in vivo. Acute pulmonary injury were observed by pulmonary function assessment and H.E. staining. The lipid metabolic profile was also altered with increased phospholipid and sphingolipid metabolites in broncho-alveolar lavage fluid (BALF) after PM_2.5 instillation. Organic component analysis revealed that benzo[a]pyrene (BaP) is one of the most abundant and toxic components in the PM_2.5 collected on the fiber filter. In vitro, BaP was used to treat A549 cells, an alveolar type II cell line. BaP (4 μM, 24 h) induced inflammation in the cells. Metabolomics analysis revealed that BaP (4 μM, 6 h) treatment altered the cellular lipid metabolic profile with increased phospholipid metabolites and reduced sphingolipid metabolites and free fatty acids (FFAs). The proportion of ω–3 polyunsaturated fatty acid (PUFA) was also decreased. Mechanically, BaP (4 μM) increased the phospholipase A2 (PLA2) activity at 4 h as well as the mRNA level of Pla2g2a at 12 h. The pro-inflammatory effect of BaP was reversed by the cytosolic PLA2 (cPLA2) inhibitor and chelator of intracellular Ca²⁺. This study revealed that BaP, as a component of PM_2.5, induces pulmonary injury by activating PLA2 and elevating lysophosphatidylcholine (LPC) in a Ca²⁺-dependent manner in the alveolar type II cells.

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PM_2.5 instillation increases pro-inflammatory lipid metabolism in the lung.

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BaP promotes the metabolism of phospholipid in alveolar type II cells.

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BaP activates cPLA2 in a Ca²⁺-dependent manner in alveolar type II cells.

Pulmonary injury associated with radiation therapy - Assessment, complications and therapeutic targets

Pulmonary injury is more common in patients undergoing radiation therapy for lungs and other thoracic malignancies. Recently with the use of most-advanced technologies powerful doses of radiation can be delivered directly to tumor site with exquisite precision. The awareness of technical and clinical parameters that influence the chance of radiation induced lung injury is important to guide patient selection and toxicity minimization strategies. At the cellular level, radiation activates free radical production, leading to DNA damage, apoptosis, cell cycle changes, and reduced cell survival. Preclinical research shows the potential for therapies targeting transforming growth factor-β (TGF-B), Toll like receptor (TLRs), Tumour necrosis factor-alpha (TNF-alpha), Interferon gamma (IFN-γ) and so on that may restore lung function. At present Amifostine (WR-2721) is the only approved broad spectrum radioprotector in use for patients undergoing radiation therapy. Newer techniques also offer the opportunity to identify new biomarkers and new targets for interventions to prevent or ameliorate these late effects of lung damage.

Role of TRPA1 in acute cardiopulmonary toxicity of inhaled acrolein

Acrolein is a highly toxic, volatile, unsaturated aldehyde generated during incomplete combustion as in tobacco smoke and indoor fires. Because the transient receptor potential ankyrin 1 (TRPA1) channel mediates tobacco smoke-induced lung injury, we assessed its role in high-level acrolein-induced toxicity in mice. Acrolein (100-275ppm, 10-30min) caused upper airway epithelial sloughing, bradypnea and oral gasping, hypothermia, cardiac depression and mortality. Male wild-type mice (WT, C57BL/6; 5-52weeks) were significantly more sensitive to high-level acrolein than age-matched, female WT mice. Both male and female TRPA1-null mice were more sensitive to acrolein-induced mortality than age- and sex-matched WT mice. Acrolein exposure increased lung weight:body weight ratios and lung albumin and decreased plasma albumin to a greater extent in TRPA1-null than in WT mice. Lung and plasma protein-acrolein adducts were not increased in acrolein-exposed TRPA1-null mice compared with WT mice. To assess TRPA1-dependent protective mechanisms, respiratory parameters were monitored by telemetry. TRPA1-null mice had a slower onset of breathing rate suppression ('respiratory braking') than WT mice suggesting TRPA1 mediates this protective response. Surprisingly, WT male mice treated either with a TRPA1 antagonist (HC030031; 200mg/kg) alone or with combined TRPA1 (100mg/kg) and TRPV1 (capsazepine, 10mg/kg) antagonists at 30min post-acrolein exposure (i.e., "real world" delay in treatment) were significantly protected from acrolein-induced mortality. These data show TRPA1 protects against high-level acrolein-induced toxicity in a sex-dependent manner. Post-exposure TRPA1 antagonism also protected against acrolein-induced mortality attesting to a complex role of TRPA1 in cardiopulmonary injury.

Cationic liposomes containing antioxidants reduces pulmonary injury in experimental model of sepsis: Liposomes antioxidants reduces pulmonary damage

The intracellular redox state of alveolar cells is a determining factor for tolerance to oxidative and pro-inflammatory stresses. This study investigated the effects of intratracheal co-administration of antioxidants encapsulated in liposomes on the lungs of rats subjected to sepsis. For this, male rats subjected to sepsis induced by lipopolysaccharide from Escherichia coli or placebo operation were treated (intratracheally) with antibiotic, 0.9% saline and antioxidants encapsulated or non-encapsulated in liposomes. Experimental model of sepsis by cecal ligation and puncture (CLP) was performed in order to expose the cecum. The cecum was then gently squeezed to extrude a small amount of feces from the perforation site. As an index of oxidative damage, superoxide anions, lipid peroxidation, protein carbonyls, catalase activity, nitrates/nitrites, cell viability and mortality rate were measured. Infected animals treated with antibiotic plus antioxidants encapsulated in liposomes showed reduced levels of superoxide anion (54% or 7.650±1.263 nmol/min/mg protein), lipid peroxidation (33% or 0.117±0.041 nmol/mg protein), protein carbonyl (57% or 0.039 ± 0.022 nmol/mg protein) and mortality rate (3.3%), p value <0.001. This treatment also reduced the level of nitrite/nitrate and increased cell viability (90.7%) of alveolar macrophages. Taken togheter, theses results support that cationic liposomes containing antioxidants should be explored as coadjuvants in the treatment of pulmonary oxidative damage.

Continuous venovenous hemofiltration decreases mortality and ameliorates acute lung injury in canine model of severe salt water drowning

Background

Pulmonary edema is an important cause of complications and death in severe drowning. Continuous veno-venous hemofiltration (CVVH) may reduce pulmonary edema and thus may be a treatment modality for severe sea water drowning resuscitation.

Methos

20 dogs were anesthetized and tracheally intubated. 10 ml/kg of sea water was infused into trachea in a minute. All animals developed signs of respiratory distress and severe hypoxia (PaO₂ < 40 mmHg) within 15 minutes after infusion. They were then mechanical ventilated and randomized to receive either CVVH (n = 10) or no additional treatment (control, n = 10) and followed over 4 hours. Arterial gas, hemodynamic parameters, and the levels of circulating inflammatory cytokines including interleukin 6 (IL-6), interleukin 8 (IL-8), and tumor necrosis factor α (TNFα) were determined. Additionally, blood endothelin and the levels of oxidative stress in lung were measured at sacrifice.

Results

5 animals in the control group (50 %) died within 4 hours after sea water aspiration, while 10 animals received CVVH all survived (p < 0.05). Importantly, CVVH significantly improved blood gas exchange as evidenced by higher PaO_2, normal oxygen saturation, and no carbon dioxide retention after 3 hour of CVVH, while also correcting against acidosis. Levels of circulating IL-6, IL-8, and TNFα were elevated in control but not in CVVH group (p < 0.01). CVVH also reduced plasma endothelin and alleviated oxidative stress. Histology examination further revealed reductions in pulmonary alveolar injury, blood congestion, and inflammation by CVVH.

Discussion and conclusions

CVVH decreased mortality and pulmonary injury and largely maintained hemodynamic and acid-base balance in animals with severe sea water drowning and thus, may be added as a new measure to aid in resuscitation from severe sea water drowning.

Trial registration

Animal protocol number: FZG0001859 http://www.fzzyy.com.

Effects of Th1 and Th2 cells balance in pulmonary injury induced by nano titanium dioxide

To explore the potential immunoregulatory mechanisms linking nano TiO₂ and pulmonary injury, Sprague Dawley rats were exposed by intra-tracheal instillation to nano TiO₂ with the individual doses of 0.5, 4.0 and 32 mg/kgb.w., micro TiO₂ with 32 mg/kgb.w. and 0.9% NaCl, respectively. The exposure was conducted twice a week, for four consecutive weeks. The results of lung histology demonstrated increased macrophages accumulation, extensive disruption of alveolar septa, slight alveolar thickness and expansion hyperemia. Mitochondria tumefaction organelles dissolution, endoplasmic reticulum expansion and the gap of nuclear broadening were shown. The changes of IFN-γ and IL-4 level showed no statistical difference. The mRNA expression of GATA-3 was up-regulated, whereas T-bet was significantly down-regulated. The protein expression of T-bet decreased and there were significant differences in nano 4 and 32 mg/kg groups. The imbalance of Th1/Th2 cytokines might be one of the mechanisms of immunotoxicity of respiratory system induced by nano TiO₂ particles.

Neutrophil depletion-but not prevention of Kupffer cell activation-decreases the severity of cerulein-induced acute pancreatitis

AIM: To determine whether neutrophil depletion and Kupffer cell inhibition might combine their protective effects to decrease the severity of acute pancreatitis.

METHODS: Mice had cerulein administration to induce acute pancreatitis and were pretreated with either anti-mouse neutrophil serum or gadolinium chloride (GdCl₃) to prevent Kupffer cell activation, or both treatments. Injury was assessed in pancreas and lungs. Myeloperoxidases (MPO) assessed neutrophil infiltration. Interleukin-6 (IL-6) and IL-10 were measured in serum, pancreas, lungs and liver.

RESULTS: In mice with acute pancreatitis, neutrophil depletion reduced the severity of pancreatitis and pancreatitis-associated lung injury. Kupffer cell inactivation by GdCl₃ had less protective effect, although IL-6 and IL-10 concentrations were significantly decreased. The protective treatment brought by neutrophil depletion was not enhanced by Kupffer cell inactivation and both treatments did not combine their protective effects.

CONCLUSION: Our results confirm the role of activated neutrophils in aggravating organ injury in acute pancreatitis while the role of Kupffer cell activation is less obvious.