Lung Tissue Homogenates Research Articles

Development of a Mass Spectrometry Imaging Method for Detecting and Mapping Graphene Oxide Nanoparticles in Rodent Tissues.

Graphene-based nanoparticles are continuously being developed for biomedical applications, and their use raises concerns about their environmental and biological impact. In the literature, some imaging techniques based on fluorescence and radioimaging have been used to explore their fate in vivo. Here, we report on the use of label-free mass spectrometry and mass spectrometry imaging (MSI) for graphene oxide (GO) and reduced graphene oxide (rGO) analyses in rodent tissues. Thereby, we extend previous work by focusing on practical questions to obtain reliable and meaningful images. Specific radical anionic carbon clusters ranging from C2-• to C9-• were observed for both GO and rGO species, with a base peak at m/z 72 under negative laser desorption ionization mass spectrometry (LDI-MS) conditions. Extension to an LDI-MSI method was then performed, thus enabling the efficient detection of GO nanoparticles in lung tissue sections of previously exposed mice. The possibility of quantifying those nanoparticles on tissue sections has also been investigated. Two different ways of building calibration curves (i.e., GO suspensions spotted on tissue sections, or added to lung tissue homogenates) were evaluated and returned similar results, with linear dynamic concentration ranges over at least 2 orders of magnitude. Moreover, intra- and inter-day precision studies have been assessed, with relative standard deviation below 25% for each concentration point of a calibration curve. In conclusion, our study confirms that LDI-MSI is a relevant approach for biodistribution studies of carbon-based nanoparticles, as quantification can be achieved, provided that nanoparticle suspension and manufacturing are carefully controlled.

Myeloperoxidase inhibition decreases morbidity and oxidative stress in mice with cystic fibrosis-like lung inflammation

BackgroundCystic fibrosis (CF) lung disease is characterized by severe bacterial infections, excessive neutrophilic inflammation and oxidative stress. The neutrophil enzyme myeloperoxidase (MPO), which produces hypochlorous acid, is associated with worse disease outcomes. Therefore, pharmacological inhibition of MPO in the airways has therapeutic potential. We investigated whether treating mice with an MPO inhibitor during pulmonary infection decreases oxidative stress and improves infection outcomes in mice with CF-like lung inflammation without impacting on bacterial clearance. MethodsTransgenic β-epithelial sodium channel (βENaC)-overexpressing mice (n = 10) were infected with Burkholderia multivorans and treated twice daily with the MPO inhibitor AZM198 (125 μmol/kg) or vehicle administered by oral gavage for two days. Bodyweight was recorded daily. MPO activity, markers of oxidative stress, inflammatory cytokines and leukocytes numbers were measured in bronchoalveolar lavage fluid (BALF). Bacterial burden was determined in lung tissue homogenates. ResultsDuring the course of infection, mice treated with AZM198 lost less weight than vehicle-treated mice (p < 0.01). MPO activity and glutathione sulfonamide, a hypochlorous acid-specific glutathione oxidation product, were significantly lower in BALF from AZM198-treated mice (p < 0.05). The inflammatory cytokines CXCL1 and TNF-α in BALF and bacterial burden in the lung were not significantly different between treated and control mice. ConclusionsOrally administered AZM198 inhibits MPO activity in epithelial lining fluid. Blocking hypochlorous acid production in epithelial lining fluid during pulmonary infections through inhibition of MPO improves morbidity in mice with CF-like lung inflammation without interfering with clearance of bacteria. Pharmacological inhibition of MPO is an approach to limit destructive oxidative stress in cystic fibrosis lung disease in humans.

Increased Arginase Expression and Decreased Nitric Oxide in Pig Donor Lungs after Normothermic Ex Vivo Lung Perfusion.

An established pig lung transplantation model was used to study the effects of cold ischemia time, normothermic acellular ex vivo lung perfusion (EVLP) and reperfusion after lung transplantation on l-arginine/NO metabolism in lung tissue. Lung tissue homogenates were analyzed for NO metabolite (NOx) concentrations by chemiluminescent NO-analyzer technique, and l-arginine, l-ornithine, l-citrulline and asymmetric dimethylarginine (ADMA) quantified using liquid chromatography-mass spectrometry (LC-MS/MS). The expression of arginase and nitric oxide synthase (NOS) isoforms in lung was measured by real-time polymerase chain reaction. EVLP preservation resulted in a significant decrease in concentrations of NOx and l-citrulline, both products of NOS, at the end of EVLP and after reperfusion following transplantation, compared to control, respectively. The ratio of l-ornithine over l-citrulline, a marker of the balance between l-arginine metabolizing enzymes, was increased in the EVLP group prior to reperfusion. The expression of both arginase isoforms was increased from baseline 1 h post reperfusion in EVLP but not in the no-EVLP group. These data suggest that EVLP results in a shift of the l-arginine balance towards arginase, leading to NO deficiency in the lung. The arginase/NOS balance may, therefore, represent a therapeutic target to improve lung quality during EVLP and, subsequently, transplant outcomes.

Effects of Pelargonium sidoides and Coptis Rhizoma 2 : 1 Mixed Formula (PS + CR) on Ovalbumin-Induced Asthma in Mice.

Pelargonium sidoides (PS) is traditionally used to treat respiratory and gastrointestinal infections, dysmenorrhea, and hepatic disorders in South Africa. Coptis Rhizoma (CR) is used to treat gastroenteric disorders, cardiovascular diseases, and cancer in East Asia. In the present study, we intended to observe the possible beneficial antiasthma effects of PS and CR on the ovalbumin- (OVA-) induced asthma C57BL/6J mice. Asthma in mice was induced by OVA sensitization and subsequent boosting. PS + CR (300 and 1,000 mg/kg; PO) or dexamethasone (IP) was administered once a day for 16 days. The changes in the body weight and gains, lung weights and gross inspections, total and differential cell counts of leukocytes in bronchoalveolar lavage fluid (BALF), serum OVA-specific immunoglobulin E (OVA-sIgE) levels, interleukin-4 (IL-4) and IL-5 levels in BALF and lung tissue homogenate, and IL-4 and IL-5 mRNA levels in lung tissue homogenates were analyzed with lung histopathology: mean alveolar surface area (ASA), alveolar septal thickness, numbers of inflammatory cells, mast cells, and eosinophils infiltrated in the alveolar regions, respectively. Significant increases in lung weights, total and differential cell counts of leukocytes in BALF, serum OVA-sIgE levels, and IL-4 and IL-5 levels in BALF and lung tissue homogenate were observed in OVA control as compared to those of intact control. In addition, OVA control showed a significant decrease in mean ASA and increases in alveolar septal thickness, numbers of inflammatory cells, mast cells, and eosinophils infiltrated in alveolar regions. However, these allergic and inflammatory asthmatic changes were significantly inhibited by PS + CR in a dose-dependent manner. In this study, PS + CR showed dose-dependent beneficial effects on OVA-induced asthma in mice through anti-inflammatory and antiallergic activities. Therefore, it is expected that PS + CR have enough potential as a new therapeutic agent or as an ingredient of a medicinal agent for various allergic and inflammatory respiratory diseases including asthma.

Pharmacological and toxicological evaluation of two anti-asthmatic polyherbal formulations.

The study aim was to evaluate the toxic potential of two polyherbal formulation i.e. " PH 1 & PH 2" and scientific validation of their anti-asthmatic use. Acute oral toxicity study as per OECD 425 TG was conducted. For validation of anti-asthmatic claim, in vivo assay named Ovalbumin (OVA)-induced murine method in Wistar rats was used. Eosinophils and IgE antibody were quantified post-administration of low and high doses of the formulations. No mortality was observed in acute toxicity study. Elevated levels of alkaline phosphatase and damaged liver structure indicating the hepatotoxicity were more pronounced in PH 2 treated rats. Congestion in kidney tissue and increased urea level were evident of the nephrotoxic nature of PH 2 in animals. Treatment with selected polyherbal products decreased the MDA level while increasing the SOD and GSH levels in lung tissue homogenates. The maximum decrease in IgE load (3.18 ± 0.08 IU/mL) was found in rats treated with 12 mg/kg dose of PH 1 followed by 100 mg/kg dose of PH 2 (3.44 ± 0.06 IU/mL). It was concluded that both polyherbal formulations had anti-asthmatic activities, however, PH 1 exhibited the liver and kidney toxicity and should be cautiously used.

Myxopyrum serratulum ameliorates airway inflammation in LPS-stimulated RAW 264.7 macrophages and OVA-induced murine model of allergic asthma

Ethnopharmacological relevanceMyxopyrum serratulum A. W. Hill. (Oleaceae) is a traditionally used Indian medicinal plant for the treatment of cough, asthma and many other inflammatory diseases. Aim of the studyIn this study, the protective effects of M. serratulum on airway inflammation was investigated in ovalbumin (OVA)-induced murine model of allergic asthma and lipopolysaccharide (LPS)-stimulated inflammation in RAW 264.7 murine macrophages, and the possible mechanisms were elucidated. Materials and methodsThe phytochemicals present in the methanolic leaf extract of M. serratulum (MEMS) were identified by reverse phase high performance liquid chromatography (RP-HPLC) analysis. In vitro anti-inflammatory activity of MEMS were evaluated by estimating the levels of nitric oxide (NO), reactive oxygen species (ROS) and cytokines (IL-1α, IL-1β, IL-2, IL-4, IL-6, IL-10, IL-12, IL-17A, IFN-γ, TNF-α, G-CSF and GM-CSF) in LPS-stimulated RAW 264.7 macrophages. In vivo anti-asthmatic activity of MEMS was studied using OVA-induced murine model. Airway hyperresponsiveness (AHR), was measured; total and differential cell counts, eosinophil peroxidase (EPO), prostaglandin E2 (PGE2), NO, ROS, and cytokines (IL-4, IL-5 and IL-13), were estimated in bronchoalveolar lavage fluid (BALF). Serum total IgE level was measured; and the histopathological changes of lung tissues were observed. The expressions of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) in lung tissue homogenates were detected by Western blot. ResultsThe chromatographic analysis of MEMS identified the presence of gallic acid, protocatechuic acid, catechin, ellagic acid, rutin, p-coumaric acid, quercetin, naringenin and apigenin. MEMS (125 and 250 μg/mL) dose-dependently reduced the levels of NO, ROS and pro-inflammatory cytokines in LPS-stimulated RAW 264.7 macrophages. MEMS (200 and 400 mg/kg, p.o.) significantly (p < 0.05) alleviated AHR; number of inflammatory cells, EPO, PGE2, NO, ROS, and cytokines (IL-4, IL-5 and IL-13) in BALF; serum total IgE and the histopathological changes associated with lung inflammation. Western blot studies showed that MEMS substantially suppressed COX-2 and iNOS protein expressions in the lung tissues of OVA-sensitized/challenged mice. ConclusionsThe present study corroborates for the first time the ameliorative effects of MEMS on airway inflammation by reducing the levels of oxidative stress, pro-inflammatory cytokines and inhibiting COX-2, iNOS protein expressions, thereby validating the ethnopharmacological uses of M. serratulum.

5-HT2 receptor activation alleviates airway inflammation and structural remodeling in a chronic mouse asthma model

AimsAlthough the bulk of research into the biology of serotonin 5-HT2A receptors has focused on its role in the CNS, selective activation of these receptors in peripheral tissues can produce profound anti-inflammatory effects. We previously demonstrated that the small molecule 5-HT2 receptor agonist (R)-2,5-dimethoxy-4-iodoamphetamine [(R)-DOI] inhibits TNF-α-mediated proinflammatory signaling cascades and inflammation via 5-HT2A receptor activation and prevents the development of, and inflammation associated with, acute allergic asthma in a mouse ovalbumin (OVA) model. Here, we investigated the ability of (R)-DOI to reverse inflammation and symptoms associated with established asthma in a newly developed model of chronic asthma. MethodsAn 18-week ovalbumin challenge period was performed to generate persistent, chronic asthma in BALB/c mice. Four once daily intranasal treatments of (R)-DOI were administered one week after allergen cessation, with respiratory parameters being measured by whole-body plethysmography (WBP). Cytokine and chemokine levels were measured by quantitative real-time polymerase chain reaction (qRT-PCR) in homogenized lung tissue, bronchoalveolar (BALF) fluid was analyzed for chemokine modulation by multiplex assays, and Periodic Acid-Schiff and Masson's Trichrome staining was performed to determine goblet cell infiltration and overall changes to lung morphology. Key findings5-HT2 activation via (R)-DOI attenuates elevated airway hyperresponsiveness to methacholine, reduces pulmonary inflammation and mucus production, and reduces airway structural remodeling and collagen deposition by nearly 70%. SignificanceOverall, these data provide support for the therapeutic potential of (R)-DOI and 5-HT2 receptor activation for the treatment of asthma, and identifies (R)-DOI as a novel therapeutic compound against pulmonary fibrosis.

The Innate Immune Protein S100A9 Protects from T-Helper Cell Type 2-mediated Allergic Airway Inflammation.

Calprotectin is a heterodimer of the proteins S100A8 and S100A9, and it is an abundant innate immune protein associated with inflammation. In humans, calprotectin transcription and protein abundance are associated with asthma and disease severity. However, mechanistic studies in experimental asthma models have been inconclusive, identifying both protective and pathogenic effects of calprotectin. To clarify the role of calprotectin in asthma, calprotectin-deficient S100A9-/- and wild-type (WT) C57BL/6 mice were compared in a murine model of allergic airway inflammation. Mice were intranasally challenged with extracts of the clinically relevant allergen, Alternaria alternata (Alt Ext), or PBS every third day over 9 days. On Day 10, BAL fluid and lung tissue homogenates were harvested and allergic airway inflammation was assessed. Alt Ext challenge induced release of S100A8/S100A9 to the alveolar space and increased protein expression in the alveolar epithelium of WT mice. Compared with WT mice, S100A9-/- mice displayed significantly enhanced allergic airway inflammation, including production of IL-13, CCL11, CCL24, serum IgE, eosinophil recruitment, and airway resistance and elastance. In response to Alt Ext, S100A9-/- mice accumulated significantly more IL-13+IL-5+CD4+ T-helper type 2 cells. S100A9-/- mice also accumulated a significantly lower proportion of CD4+ T regulatory (Treg) cells in the lung that had significantly lower expression of CD25. Calprotectin enhanced WT Treg cell suppressive activity in vitro. Therefore, this study identifies a role for the innate immune protein, S100A9, in protection from CD4+ T-helper type 2 cell hyperinflammation in response to Alt Ext. This protection is mediated, at least in part, by CD4+ Treg cell function.

Molecular Identification of a Novel Hantavirus in Malaysian Bronze Tube-Nosed Bats (Murina aenea).

In the past ten years, several novel hantaviruses were discovered in shrews, moles, and bats, suggesting the dispersal of hantaviruses in many animal taxa other than rodents during their evolution. Interestingly, the coevolutionary analyses of most recent studies have raised the possibility that nonrodents may have served as the primordial mammalian host and harboured the ancestors of rodent-borne hantaviruses as well. The aim of our study was to investigate the presence of hantaviruses in bat lung tissue homogenates originally collected for taxonomic purposes in Malaysia in 2015. Hantavirus-specific nested RT-PCR screening of 116 samples targeting the L segment of the virus has revealed the positivity of two lung tissue homogenates originating from two individuals, a female and a male of the Murina aenea bat species collected at the same site and sampling occasion. Nanopore sequencing of hantavirus positive samples resulted in partial genomic data from S, M, and L genome segments. The obtained results indicate molecular evidence for hantaviruses in the M. aenea bat species. Sequence analysis of the PCR amplicon and partial genome segments suggests that the identified virus may represent a novel species in the Mobatvirus genus within the Hantaviridae family. Our results provide additional genomic data to help extend our knowledge about the evolution of these viruses.

Mimicking in-vivo exposures to drug combinations in-vitro: anti-tuberculosis drugs in lung lesions and the hollow fiber model of infection

Here, we evaluate protocol requirements to mimic therapeutically relevant drug concentrations at the site of infection (i.e. lung lesion) in an in-vitro hollow fibre model of infection using pulmonary tuberculosis as a paradigm. Steady-state pharmacokinetic profiles in plasma, lung tissue and lung lesion homogenate were simulated for isoniazid, rifampicin and pyrazinamide and moxifloxacin. An R-shiny User Interface was developed to support conversion of in-vivo pharmacokinetic CMAX, TMAX and T1/2 estimates into pump settings. A monotherapy protocol mimicking isoniazid in lung lesion homogenate (isoniazid CMAX = 1,200 ng/ml, TMAX = 2.2 hr and T1/2 = 4.7 hr), and two combination therapy protocols including drugs with similar (isoniazid and rifampicin (CMAX = 400 ng/ml)) and different half-lives (isoniazid and pyrazinamide (CMAX = 28,900 ng/ml and T1/2 = 8.0 hr)) were implemented in a hollow-fiber system. Drug levels in the perfusate were analysed using ultra-high-performance liquid chromatographic-tandem mass spectrometric detection. Steady state pharmacokinetic profiles measured in the hollow fiber model were similar to the predicted in-vivo steady-state lung lesion homogenate pharmacokinetic profiles. The presented approach offers the possibility to use pharmacological data to study the effect of target tissue exposure for drug combinations. Integration with pharmacokinetics modelling principles through a web interface will provide access to a wider community interested in the evaluation of efficacy of anti-tubercular drugs.

Influence regulation of inflammatory immune response by interleukin-17 lipopolysaccharide-induced acute lung injury in mice

To explore the immunomodulatory effects of interleukin-17 (IL-17) on acute lung injury (ALI) induced by lipopolysaccharide (LPS). Thirty-six SPF-class C57BL/6 mice were divided into normal saline control group (NS group) and LPS-induced ALI model group (LPS group, LPS 5 mg/kg intratracheal drip) according to random number table method, with 18 mice in each group. Six mice were sacrificed at 2, 6 and 24 hours after model reproduction, and peripheral blood, lung and spleen tissues were harvested. After staining with hematoxylin-eosin (HE), the pathological changes of lung tissue were observed under microscope and the infiltration level of lymphocytes, neutrophils and macrophages in the alveolar wall and tracheal wall were detected. Immunohistochemistry was used to detect the protein expression of IL-17 in alveolar wall and tracheal wall, and the correlation between IL-17 expression and lymphocytes, neutrophils and macrophages infiltration in alveolar wall and tracheal wall were analyzed. The level of IL-17 in lung tissue homogenate was determined by enzyme linked immunosorbent assay (ELISA). Flow cytometry was used to detect the proportion of CD4+IL-17+ helper T cells (Th17 cells) in CD4+ T cells in peripheral blood, lung tissue and spleen tissue. (1) Microscopy showed that the lung tissue structure of NS group was basically normal at each time after model reproduction, and there was no obvious inflammatory cell infiltration, while the lung tissue edema and inflammatory reaction were gradually aggravated in the LPS group, and the lung injury score was significantly higher than that in NS group at each time (2 hours: 4.47±1.42 vs. 1.10±0.55, 6 hours: 7.93±2.14 vs. 1.23±0.50, 24 hours: 12.67±2.67 vs. 1.20±0.61, all P < 0.01). (2) Immunohistochemistry showed that the protein expression of IL-17 in alveolar wall and tracheal wall of LPS group increased gradually with time, while that in NS group was negative or weak positive. Quantitative analysis showed that the immunohistochemical staining score of IL-17 protein in alveolar wall and tracheal wall of LPS group were higher than those of NS group (alveolar wall: 2.70±1.40 vs. 0.90±0.37 at 2 hours, 5.10±1.76 vs. 1.17±0.59 at 6 hours, 9.67±1.32 vs. 1.10±0.45 at 24 hours; tracheal wall: 2.87±0.89 vs. 0.90±0.39 at 2 hours, 4.97±1.48 vs. 1.10±0.41 at 6 hours, 8.67±1.54 vs. 1.03±0.29 at 24 hours; all P < 0.05). (3) Correlation analysis showed that the protein expression of IL-17 in alveolar wall and tracheal wall were positively correlated with the degree of lymphocyte, neutrophil and macrophage infiltration (alveolar wall: r value was 0.632, 0.550, 0.466; tracheal wall: r value was 0.695, 0.662, 0.575, respectively; all P < 0.01). (4) IL-17 content (μg/L) in lung tissue homogenate was significantly higher than that in NS group at each time after model reproduction (2 hours: 1.37±0.14 vs. 1.01±0.18, 6 hours: 1.65±0.19 vs. 1.11±0.18, 24 hours: 1.92±0.36 vs. 1.17±0.24, all P < 0.01). (5) The proportion of Th17 cells in the peripheral blood, lung tissue and spleen tissue of the LPS group were higher than those of the NS group at each time after model reproduction [peripheral blood: (2.62±0.62)% vs. (1.42±0.40)% at 2 hours, (3.74±0.43)% vs. (1.27±0.32)% at 6 hours, (4.44±0.65)% vs. (1.59±0.45)% at 24 hours; lung tissue: (2.32±0.44)% vs. (1.50±0.25)% at 2 hours, (3.66±0.36)% vs. (1.33±0.24)% at 6 hours, (4.60±0.54)% vs. (1.60±0.27)% at 24 hours; spleen tissue: (1.49±0.36)% vs. (0.69±0.21)% at 2 hours, (2.58±0.55)% vs. (0.59±0.18)% at 6 hours, (3.76±0.57)% vs. (0.65±0.26)% at 24 hours; all P < 0.01]. IL-17 is involved in the inflammatory immune regulation of ALI mice.

Protective effect of a polyphenols-rich extract from Inonotus Sanghuang on bleomycin-induced acute lung injury in mice

Mushroom Phellinus linteus (“Sanghuang” in Chinese) is a popular medicinal polypore used to treat several disorders through its various biological functions. Inonotus sanghuang is claimed to produce general immune-potentiating and strengthening, anti-inflammatory, anti-tumor and anti-microbial properties, but its effect on acute lung inflammation and oxidative stress are not clearly understood. To determine the effect and mechanism of the polyphenols-rich ethyl acetate fraction from wild I. sanghuang extract (ISE) on acute lung injury (ALI) induced by bleomycin (BLM), female C57BL/6 mice were fed ISE (0%, 0.15% or 0.6% in diet) for 4 weeks prior to challenge with BLM. Bronchoalveolar lavage fluid (BALF) from lung, spleen and lung tissues were collected on day 3 after BLM challenge for histological, oxidative stress, molecular and biochemical analysis. ISE supplementation improved pathological features in lung injury scores and reduced lung wet-to-dry ratios. Moreover, ISE reduced inflammatory cell infiltration and the pro-inflammatory cytokines including IL-1β, IL-6 and TNF-α in BALF, decreased the MPO activity and the MDA level and increased the SOD, CAT and GSH-Px activities in lung tissue homogenates. Further mechanism analysis demonstrated that dietary ISE inhibited NF-κB signal. Finally, peripheral immune function analysis showed that ISE had less effect on immune response including splenocyte producing inflammatory cytokines and T cell proliferation except for IL-1β and IL-2. Our findings indicate the possibility that dietary ISE attenuates ALI induced by BLM through correcting the inflammation and oxidation balance at least in part via inhibiting NF-κB signal in vivo, suggesting that ISE might be a valuable medicinal food effective in improving lung injury.

Bioanalytical assay for the novel TRK inhibitor selitrectinib in mouse plasma and tissue homogenates using liquid chromatography-tandem mass spectrometry

Selitrectinib is a next generation tropomyosin receptor kinase (TRK) inhibitor developed to overcome acquired resistance to first generation TRK inhibitors. The drug is a cyclic analogue of larotrectinib. An existing bioanalytical assay for larotrectinib was therefore redesigned for selitrectinib. The assay used liquid chromatography-electrospray tandem mass spectrometry in positive selected reaction monitoring mode. Mouse plasma and tissue homogenates of brain, heart, kidney, liver, lung, small intestine, spleen, and testis were pretreated using acetonitrile protein precipitation with larotrectinib added as internal standard. Successful validation using current guidelines was obtained in the range 0.5–1000 ng/ml. Precision was within 5–12% and accuracy within 91–108% for all matrices investigated. The drug was stable in all matrices under the relevant storage conditions. Pharmacokinetics and tissue distribution of selitrectinib were monitored in a pilot study in mice demonstrating the applicability of the presented assay.

Measurement of Free Drug Concentration from Biological Tissue by Solid-Phase Microextraction: In Silico and Experimental Study.

In this article, the use of an SPME technique is reported for the first time for direct measurement of free drug concentration in solid tissue. In our investigations, we considered doxorubicin (DOX) spiked in homogenized tissue matrix at transient and equilibrium extraction conditions, with subsequent assessment of obtained experimental results by an in silico approach using mathematical models developed in COMSOL Multyphysics. In silico studies were performed on the basis of transported diluted species (tds) and reaction engineering (re) modules from COMSOL Multiphysics, using the same conditions as those used to attain experimental results. To determine the apparent binding affinity of DOX to the tissue matrix which contains multiple binding species, the experimentally determined binding affinity of DOX with human serum albumin (HSA) was considered to simplify the mathematical calculations. Here, the value of the binding affinity was considered for a single binding site and adjusted by fitting the experimental results with the mathematical model. Bovine lung tissue homogenate was selected as a surrogate matrix, and a biocompatible C-8 commercial SPME fiber was used for extraction of DOX. In total, four mathematical models were herein developed to describe the mass transfer kinetics of solid coatings: in agar gel at static conditions, in PBS solution with agitated conditions, extraction in PBS solution in the presence of an HSA binding matrix, and static extraction in homogenized lung tissue. For all conditions, simulated results were in good agreement with experimental results. The developed mathematical model allows for measurements of free drug concentrations inside the tissue matrix and facilitates calculations of local depletion of DOX by a solid SPME coating. Results of the investigations indicate that local depletion of the free form of DOX, even at the kinetic stage, is negligible for tissue extraction, as the release of the heavily bound analyte (over 99% binding to tissue matrix) is very rapid, thus easily compensating for the loss of the drug to the SPME coating. This indicates that the dissociation rate constant of DOX from lung tissue components is very rapid; therefore, the mass transfer of drug to the fiber coating via free from is very efficient. Our results also indicate that thin coating SPME fibers provide a good way to measure drug distribution after dosing, as extractions via thin coating SPME fibers do not affect the free concentration of the drug, which is responsible for drug distribution in tissue.

Analysis of health and lung injury markers in mice treated with TLR4-interacting SPA4 peptide

Abstract The SPA4 peptide (GDFRYSDGTPVNYTNWYRGE) interacts with TLR4, affects intracellular signaling, improves host defense, and alleviates tissue injury in mouse models of bacterial lung infection and lipopolysaccharide-induced lung inflammation. In this study, we investigated the effect of different doses of SPA4 peptide on health, and systemic and lung injury parameters in outbred CD-1 mice. Mice were intratracheally administered with 0.625, 1.25, 2.5, 5, and 10 μg SPA4 peptide per g body weight every day for three days. Mice left untreated or those treated with equivalent volume of vehicle were included as controls. Signs of sickness and body weights were monitored every 24 h; food and water were provided ad libitum. After 24 h of last intratracheal instillation, mice were euthanized, and blood and major organs were collected. Blood gas and electrolytes (pCO2, total CO2, pO2, pH, anion gap, base excess, total hemoglobin, Na+, K+, Cl−, HCO3−) were analyzed, and markers of lung injury (lung wet/dry weight ratio, and levels of albumin, lactate, and total protein) were determined in lung tissue homogenates. Major organs (stomach, intestines, lung, liver, spleen, kidney, heart, and thymus) were fixed, sectioned, stained with hematoxylin and eosin, and examined for tissue damage or inflammatory response. No signs of sickness or changes in body weight were noted. Blood gas and electrolyte parameters were not significantly altered in SPA4 peptide-treated mice. The lung injury parameters were also not significantly different in SPA4 peptide-treated mice. Histological examination revealed no sign of tissue injury or inflammation in any of the major organs. Together, these results provide an initial safety assessment of the SPA4 peptide.

Melittin Exerts Beneficial Effects on Paraquat-Induced Lung Injuries In Mice by Modifying Oxidative Stress and Apoptosis.

Melittin (MEL) is a 26-amino acid peptide with numerous biological activities. Paraquat (PQ) is one of the most widely used herbicides, although it is extremely toxic to humans. To date, PQ poisoning has no effective treatment, and therefore the current study aimed to assess for the first time the possible effects of MEL on PQ-induced lung injuries in mice. Mice received a single intraperitoneal (IP) injection of PQ (30 mg/kg), followed by IP treatment with MEL (0.1 and 0.5 mg/kg) twice per week for four consecutive weeks. Histological alterations, oxidative stress, and apoptosis in the lungs were studied. Hematoxylin and eosin (H&E) staining indicated that MEL markedly reduced lung injuries induced by PQ. Furthermore, treatment with MEL increased superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activity, and decreased malonaldehyde (MDA) and nitric oxide (NO) levels in lung tissue homogenates. Moreover, immunohistochemical staining showed that B-cell lymphoma-2 (Bcl-2) and survivin expressions were upregulated after MEL treatment, while Ki-67 expression was downregulated. The high dose of MEL was more effective than the low dose in all experiments. In summary, MEL efficiently reduced PQ-induced lung injuries in mice. Specific pharmacological examinations are required to determine the effectiveness of MEL in cases of human PQ poisoning.

CD200-CD200R1 inhibitory signaling prevents spontaneous bacterial infection and promotes resolution of neuroinflammation and recovery after stroke

BackgroundIschemic stroke results in a robust inflammatory response within the central nervous system. As the immune-inhibitory CD200-CD200 receptor 1 (CD200R1) signaling axis is a known regulator of immune homeostasis, we hypothesized that it may play a role in post-stroke immune suppression after stroke.MethodsIn this study, we investigated the role of CD200R1-mediated signaling in stroke using CD200 receptor 1-deficient mice. Mice were subjected to a 60-min middle cerebral artery occlusion and evaluated at days 3 and 7, representing the respective peak and early resolution stages of neuroinflammation in this model of ischemic stroke. Infarct size and behavioral deficits were assessed at both time points. Central and peripheral cellular immune responses were measured using flow cytometry. Bacterial colonization was determined in lung tissue homogenates both after acute stroke and in an LPS model of systemic inflammation.ResultsIn wild-type (WT) animals, CD200R1 was expressed on infiltrating monocytes and lymphocytes after stroke but was absent on microglia. Early after ischemia (72 h), CD200R1-knockout (KO) mice had significantly poorer survival rates and an enhanced susceptibility to spontaneous bacterial colonization of the respiratory tract compared to wild-type (WT) controls, despite no difference in infarct or neurological deficits. While the CNS inflammation was resolved by day 7 post-stroke in WT mice, brain-resident microglia and monocyte activation persisted in CD200R1-KO mice, accompanied by a delayed, augmented lymphocyte response. At this time point, CD200R1-KO mice displayed greater weight loss, more severe neurological deficits, and impaired motor function compared to WT. Systemically, CD200R1-KO mice exhibited signs of persistent infection including lymphopenia, T cell activation and memory conversion, and narrowing of the TCR repertoire. These findings were confirmed in a second model of acute neuroinflammation induced by systemic endotoxin challenge.ConclusionThis study defines an essential role of CD200-CD200R1 signaling in stroke. Loss of CD200R1 led to high mortality, increased rates of post-stroke infection, and enhanced entry of peripheral leukocytes into the brain after ischemia, with no increase in infarct size. This suggests that the loss of CD200 receptor leads to enhanced peripheral inflammation that is triggered by brain injury.

Utilization of near infrared fluorescence imaging to track and quantify the pulmonary retention of single-walled carbon nanotubes in mice

As nanomaterials are used in a wide array of applications, investigations regarding health impacts associated with inhalation are a concern. Reports show that exposure to single-walled carbon nanotubes (SWCNTs) can induce fibrosis, allergic-type reactions, and pathogen susceptibility. Airway clearance is known to play a primary role in these disease states, yet SWCNT detection in biological systems is challenging. Common techniques, such as electron microscopy, lack spatial resolution and specificity to delineate SWCNTs in carbon-based organisms. Here we validated a near-infrared fluorescence imaging (NIRFI) system to track and semi-quantify SWCNTs over 21 days in tissues of mice exposed intratracheally to 1 dose of SWCNTs. In tandem, we optimized a NIRF-based spectrometry method to quantify SWCNTs, showing that NIRFI was consistent with SWCNT burdens quantified by NIRF spectroscopy in whole lung tissue homogenates. Finally, NIRFI was utilized to localize SWCNTs on lung tissue sections used for pathological analysis. Results revealed that SWCNTs remained in the lung over 21 days and were consistent with alveolar wall restructuring and granuloma formation. This study is the first to quantify SWCNTs in mouse lungs using both semi-quantitative tracking and quantitative mass measurements using NIRF, highlighting this as a sensitive and specific technique for assessing SWCNT clearance in vivo.

Molecular identification of a presumably novel hantavirus in bronze tube-nosed bat (Murina aenea) in Malaysia

Purpose: Hantaviruses (Hantaviridae) cause two types of life-threatening human diseases, hemorrhagic fever with renal syndrome (HFRS) in Eurasia and hantavirus cardiopulmonary syndrome (HCPS) in the Americas. To date, as a consensus, wild rodents were believed as natural hosts of hantaviruses. However, recent studies described several novel hantaviruses in shrews, moles and bats, suggesting the dispersal of hantaviruses in several animal taxa during their evolution. Interestingly, the co-evolutionary analyses of most recent studies have raised the possibility of bats and/or soricomorphs may have served as the primordial mammalian host and harboured the ancestors of rodent-borne hantaviruses.The aim of our study was to investigate the presence of hantaviruses in bat lung tissue homogenates originally collected for taxonomic purposes in Malaysia, 2015. Methods & Materials: Hantavirus specific nested PCR screening of 116 samples targeting the L segment of the virus have revealed the positivity of two lung tissue homogenates originating from Murina aenea bat species. Results: The obtained results indicate the first molecular evidence for hantavirus in Murina eanae bat species. Conclusion: Preliminary sequence analysis of the PCR amplicon suggest the identified virus may represents a novel species within Orthohantavirus genus. Furthermore, our results provide additional genomic data to help extend our knowledge about the evolution of these viruses and we present the first hantavirus sequence from Murina bat genus.

Antagonistic Effects of N-acetylcysteine on Mitogen-activated Protein Kinase Pathway Activation, Oxidative Stress and Inflammatory Responses in Rats with PM2.5 Induced Lung Injuries.

Objective To evaluate the antagonistic effects of N-acetylcysteine (NAC) on mitogen-activated protein kinases (MAPK) pathway activation, oxidative stress and inflammatory responses in rats with lung injury induced by fine particulate matter (PM2.5).Methods Forty eight male Wistar rats were randomly divided into six groups: blank control group (C1), water drip control group (C2), PM2.5 exposed group (P), low-dose NAC treated and PM2.5 exposed group (L), middle-dose NAC treated and PM2.5 exposed group (M), and high-dose NAC treated and PM2.5 exposed group (H). PM2.5 suspension (7.5 mg/kg) was administered tracheally once a week for four times. NAC of 125 mg/kg, 250 mg/kg and 500 mg/kg was delivered intragastrically to L, M and H group respectively by gavage (10 ml/kg) for six days before PM2.5 exposure. The histopathological changes and human mucin 5 subtype AC (MUC5AC) content in lung tissue of rats were evaluated. We investigated IL-6 in serum and bronchoalveolar lavage fluid (BALF) by Enzyme-linked immunosorbent assay (ELISA), MUC5AC in lung tissue homogenate by ELISA, glutathione peroxidase (GSH-PX) in serum and BALF by spectrophotometry, and the expression of p-ERK1/2, p-JNK1/2 and p-p38 proteins by Western blot. All the measurements were analyzed and compared statistically.Results Lung tissue of rats exposed to PM2.5 showed histological destruction and increased mucus secretion of bronchial epithelial cells. Rats receiving NAC treatment showed less histological destruction and mucus secretion. Of P, L, M and H group, MUC5AC in lung tissue, IL-6 in serum and BALF were higher than controls (C1 and C2) (all P<0.05), with the highest levels found in the P group and a decreasing trend with increase of NAC dose. The activity of GSH-PX in serum and BALF of PM2.5 exposed rats (P, L, M and H) was lower than that of controls (all P<0.05), with higher activities found in NAC treated rats (L, M, and H), and an increasing trend with increase of NAC dose. The expressions of p-ERK1/2, p-JNK1/2 and p-p38 proteins in PM2.5 exposed lung tissue (P, L, M and H) was higher than controls (all P<0.05), with decreased levels and dose dependent downregulation found in NAC treated rats.Conclusion NAC can antagonize major MAPK pathway activation, lung oxidative stress and inflammatory injury induced by PM2.5 in rats.