Histological Examination Of Lung Tissue Research Articles

Characterizing a lethal CAG-ACE2 transgenic mouse model for SARS-CoV-2 infection using Cas9-enhanced nanopore sequencing.

The SARS-CoV-2 pandemic has underscored the necessity for functional transgenic animal models for testing. Mouse lines with overexpression of the human receptor ACE2 serve as the common animal model to study COVID-19 infection. Overexpression of ACE2 under a strong ubiquitous promoter facilitates convenient and sensitive testing of COVID-19 pathology. We performed pronuclear microinjections using a 5kb CAG-ACE2 linear transgene construct and identified three founder lines with 140, 72, and 73 copies, respectively. Two of these lines were further analyzed for ACE2 expression profiles and sensitivity to SARS-CoV-2 infection. Both lines expressed ACE2 in all organs analyzed. Embryonic fibroblast cell lines derived from transgenic embryos demonstrated severe cytopathic effects following infection, even at low doses of SARS-CoV-2 (0,1-1.0 TCID50). Infected mice from the two lines began to show COVID-19 clinical signs three days post-infection and succumbed between days 4 and 7. Histological examination of lung tissues from terminally ill mice revealed severe pathological alterations. To further characterize the integration site in one of the lines, we applied nanopore sequencing combined with Cas9 enrichment to examine the internal transgene concatemer structure. Oxford Nanopore sequencing (ONT) is becoming the gold standard for transgene insert characterization, but it is relatively inefficient without targeted region enrichment. We digested genomic DNA with Cas9 and gRNA against the ACE2 transgene to create ends suitable for ONT adapter ligation. ONT data analysis revealed that most of the transgene copies were arranged in a head-to-tail configuration, with palindromic junctions being rare. We also detected occasional plasmid backbone fragments within the concatemer, likely co-purified during transgene gel extraction, which is a common occurrence in pronuclear microinjections.

A novel Saclayvirus Acinetobacter baumannii phage genomic analysis and effectiveness in preventing pneumonia

Acinetobacter baumannii, which is resistant to multiple drugs, is an opportunistic pathogen responsible for severe nosocomial infections. With no antibiotics available, phages have obtained clinical attention. However, since immunocompromised patients are often susceptible to infection, the appropriate timing of administration is particularly important. During this research, we obtained a lytic phage vB_AbaM_P1 that specifically targets A. baumannii. We then assessed its potential as a prophylactic treatment for lung infections caused by clinical strains. The virus experiences a period of inactivity lasting 30 min and produces approximately 788 particles during an outbreak. Transmission electron microscopy shows that vB_AbaM_P1 was similar to the Saclayvirus. Based on the analysis of high-throughput sequencing and bioinformatics, vB_AbaM_P1 consists of 107537 bases with a G + C content of 37.68%. It contains a total of 177 open reading frames and 14 tRNAs. No antibiotic genes were detected. In vivo experiments, using a cyclophosphamide-induced neutrophil deficiency model, tested the protective effect of phage on neutrophil-deficient rats by prophylactic application of phage. The use of phages resulted in a decrease in rat mortality caused by A. baumannii and a reduction in the bacterial burden in the lungs. Histologic examination of lung tissue revealed a decrease in the presence of immune cells. The presence of phage vB_AbaM_P1 had a notable impact on preventing A. baumannii infection, as evidenced by the decrease in oxidative stress in lung tissue and cytokine levels in serum. Our research offers more robust evidence for the early utilization of bacteriophages to mitigate A. baumannii infection.Key points•A novel Saclayvirus phage infecting A. baumannii was isolated from sewage.•The whole genome was determined, analyzed, and compared to other phages.•Assaying the effect of phage in preventing infection in neutrophil-deficient models.

COVID-19 Analysis in Tissue Samples Acquired by Minimally Invasive Autopsy in Out-of-Hospital Deaths with Postmortem Degeneration.

Minimally invasive autopsy (MIA) is an alternative to a full autopsy for the collection of tissue samples from patients' bodies using instruments such as a biopsy needle. MIA has been conducted in many cases of coronavirus disease 2019 (COVID-19) and has contributed to the elucidation of the disease pathogenesis. However, most cases analyzed are hospital deaths, and there are few reports on the application of MIA in out-of-hospital deaths with varying extents of post-mortem changes. In this study, MIA and autopsies were performed in 15 patients with COVID-19 2-30 days after death, including 11 out-of-hospital deaths. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genome detection by reverse transcriptase quantitative polymerase chain reaction using MIA samples was mostly consistent with autopsy samples, particularly lung tissue, even in out-of-hospital cases. MIA had high sensitivity and specificity (> 0.80). Histological examination of lung tissue obtained by MIA showed characteristics of COVID-19 pneumonia, with 91% agreement with autopsy samples, whereas localization of SARS-CoV-2 protein in lung tissue was indicated by immunohistochemistry, with 75% agreement. In conclusion, these results suggest that MIA is applicable to out-of-hospital deaths due to COVID-19 with various postmortem changes, especially when autopsies are not available.

Postmortem lung and heart examination of COVID-19 patients in a case series from Jordan.

Coronavirus disease 2019 (COVID-19) has emerged as a pandemic for more than 2 years. Autopsy examination is an invaluable tool to understand the pathogenesis of emerging infections and their consequent mortalities. The aim of the current study was to present the lung and heart pathological findings of COVID-19-positive autopsies performed in Jordan. The study involved medicolegal cases, where the cause of death was unclear and autopsy examination was mandated by law. We included the clinical and pathologic findings of routine gross and microscopic examination of cases that were positive for COVID-19 at time of death. Testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was confirmed through molecular detection by real-time polymerase chain reaction, serologic testing for IgM and electron microscope examination of lung samples. Seventeen autopsies were included, with male predominance (76.5%), Jordanians (70.6%), and 50 years as the mean age at time of death. Nine out of 16 cases (56.3%) had co-morbidities, with one case lacking such data. Histologic examination of lung tissue revealed diffuse alveolar damage in 13/17 cases (76.5%), and pulmonary microthrombi in 8/17 cases (47.1%). Microscopic cardiac findings were scarcely detected. Two patients died as a direct result of acute cardiac disease with limited pulmonary findings. The detection of SARS-CoV-2 in postmortem examination can be an incidental or contributory finding which highlights the value of autopsy examination to determine the exact cause of death in controversial cases.

Alcohol exacerbates SARS‐CoV‐2 ‐induced ARDS in mice

SARS‐CoV‐2 – induced COVID‐19 causes acute respiratory distress syndrome (ARDS) and multiorgan failure. COVID‐19 can also cause psycho‐social problems, including increased alcohol consumption and consequent complications. Alcohol abuse is recognized as an independent factor that increases by three‐ to four‐fold the incidence of ARDS, a severe form of acute lung injury with a mortality rate of 40 to 50 percent. This translates to tens of thousands of excess deaths in the United States each year from alcohol‐associated lung injury. We developed a combined ARDS and alcohol abuse mouse model by intratracheally instilling the S1 subunit of SARS‐CoV‐2 Spike protein in K18‐hACE2 transgenic mice that express the human angiotensin‐converting enzyme 2 (ACE2) receptor for SARS‐CoV‐2 and which are kept on an ethanol diet. 72 hours after S1SP instillation, mice kept on the ethanol diet exhibited a strong decline in body weight, a dramatic increase in white blood cell content of bronchoalveolar lavage fluid (BALF), and an augmented “cytokine storm”, compared to S1SP treated mice on control diet. Histologic examination of lung tissue demonstrated abnormal recruitment of immune cells in the alveolar space, destructive effects on parenchymal architecture, and an overall worsening of the lung injury score (LIS) of S1SP‐ and alcohol‐treated animals. Along with the activation of pro‐inflammatory biomarkers (NF‐κB, STAT3, NLRP3 inflammasome), lung tissue homogenates from mice on alcohol diet, demonstrated overexpression of ACE2 compared to mice on control diet. In summary, K18‐hACE2 transgenic mice on an alcohol diet exhibit a more severe S1SP‐induced ARDS than corresponding mice on a control diet and may thus represent a useful model for the development of therapeutic interventions against alcohol‐exacerbated COVID‐19.

Alcohol Increases Lung Angiotensin-Converting Enzyme 2 Expression and Exacerbates Severe Acute Respiratory Syndrome Coronavirus 2 Spike Protein Subunit 1–Induced Acute Lung Injury in K18-hACE2 Transgenic Mice

During the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, alcohol consumption increased markedly. Nearly one in four adults reported drinking more alcohol to cope with stress. Chronic alcohol abuse is now recognized as a factor complicating the course of acute respiratory distress syndrome and increasing mortality. To investigate the mechanisms behind this interaction, a combined acute respiratory distress syndrome and chronic alcohol abuse mouse model was developed by intratracheally instilling the subunit 1 (S1) of SARS-CoV-2 spike protein (S1SP) in K18–human angiotensin-converting enzyme 2 (ACE2) transgenic mice that express the human ACE2 receptor for SARS-CoV-2 and were kept on an ethanol diet. Seventy-two hours after S1SP instillation, mice on an ethanol diet showed a strong decrease in body weight, a dramatic increase in white blood cell content of bronchoalveolar lavage fluid, and an augmented cytokine storm, compared with S1SP-treated mice on a control diet. Histologic examination of lung tissue showed abnormal recruitment of immune cells in the alveolar space, abnormal parenchymal architecture, and worsening Ashcroft score in S1SP- and alcohol-treated animals. Along with the activation of proinflammatory biomarkers [NF-κB, STAT3, NLR family pyrin domain-containing protein 3 (NLRP3) inflammasome], lung tissue homogenates from mice on an alcohol diet showed overexpression of ACE2 compared with mice on a control diet. This model could be useful for the development of therapeutic approaches against alcohol-exacerbated coronavirus disease 2019.

Potential effect of amniotic fluid-derived stem cells on hyperoxia-induced pulmonary alveolar injury

BackgroundWith the widespread of Coronavirus Disease 2019 pandemic, in spite of the newly emerging vaccines, mutated strains remain a great obstacle to supportive and preventive measures. Coronavirus 19 survivors continue to face great danger of contacting the disease again. As long as no specific treatment has yet to be approved, a great percentage of patients experience real complications, including among others, lung fibrosis. High oxygen inhalation especially for prolonged periods is per se destructive to the lungs. Nevertheless, oxygen remains the first line support for such patients. In the present study we aimed at investigating the role of amniotic fluid-mesenchymal stem cells in preventing versus treating the hyperoxia-induced lung fibrosis in rats.MethodsThe study was conducted on adult albino rats; 5 pregnant female rats were used as amniotic fluid donors, and 64 male rats were randomly divided into two groups: Control group; where 10 rats were kept in normal atmospheric air then sacrificed after 2 months, and hyperoxia-induced lung fibrosis group, where 54 rats were exposed to hyperoxia (100% oxygen for 6 h/day) in air-tight glass chambers for 1 month, then randomly divided into the following 5 subgroups: Hyperoxia group, cell-free media-treated group, stem cells-prophylactic group, stem cells-treated group and untreated group. Isolation, culture and proliferation of stem cells were done till passage 3. Pulmonary function tests, histological examination of lung tissue under light and electron microscopes, biochemical assessment of oxidative stress, IL-6 and Rho-A levels, and statistical analysis of data were performed. F-test (ANOVA) was used for normally distributed quantitative variables, to compare between more than two groups, and Post Hoc test (Tukey) for pairwise comparisons.ResultsLabelled amniotic fluid-mesenchymal stem cells homed to lung tissue. Stem cells administration in the stem cells-prophylactic group succeeded to maintain pulmonary functions near the normal values with no significant difference between their values and those of the control group. Moreover, histological examination of lung tissues showed that stem cells-prophylactic group were completely protected while stem cells-treated group still showed various degrees of tissue injury, namely; thickened interalveolar septa, atelectasis and interstitial pneumonia. Biochemical studies after stem cells injection also showed decreased levels of RhoA and IL-6 in the prophylactic group and to a lesser extent in the treated group, in addition to increased total antioxidant capacity and decreased malondialdehyde in the stem cells-injected groups.ConclusionsAmniotic fluid-mesenchymal stem cells showed promising protective and therapeutic results against hyperoxia-induced lung fibrosis as evaluated physiologically, histologically and biochemically.

Single intratracheal exposure to SARS‐CoV‐2 S1 spike protein induces acute lung injury in K18‐hACE2 transgenic mice

The SARS‐CoV‐2 pandemic has infected more than 85,900,000 people and provoked the death of more than 1.9 million worldwide. Therapeutic options remain limited, and vaccines may exhibit narrow efficacy, due to short supplies, delays in distribution and the emergence of new resistant strains. It is mandatory to study new therapeutic approaches that modulate the strong inflammatory response observed in the lung, prevent respiratory failure and improve outcomes. The study of SARS‐CoV‐2 pathogenicity in vivo is challenging due to the necessary biosafety laboratory regulations. Thus, we developed an acute lung injury model by intratracheally instilling the S1 subunit of SARS‐CoV‐2 Spike S protein (400 µg/kg, 2 ml/kg body weight) in K18‐hACE2 transgenic mice that overexpress the human receptor for SARS‐CoV‐2 Spike protein S, ACE2, and investigated outcomes 72 hours later. Mice exhibited an acute decline in body weight during the first 48 hours following instillation, compared to saline‐instilled controls. At 72 hours, bronchoalveolar lavage fluid demonstrated a dramatic increase in white blood cell content, particularly neutrophils, and marked proteinosis compared to controls. Histologic examination of lung tissue revealed hyaline membranes, alveolar septal thickening, and a large number of neutrophils in the interstitial and alveolar spaces of Spike protein S exposed mice. We propose that a single exposure of K18‐hACE2 mice to SARS‐CoV‐2 Spike Protein S subunit S1 may represent a valid model of COVID‐19, allow the study of the molecular mechanisms of SARS‐CoV‐2 induced lung injury and be useful in the investigation of potential new therapeutic approaches to the management of COVID‐19 as well as future coronavirus‐dependent respiratory diseases.

Assessment of nicotine release from nicotine-loaded chitosan nanoparticles dry powder inhaler formulations via locomotor activity of C57BL/6 mice

PurposeThis study aimed to assess the activity of controlled release nicotine from dry powder inhaler formulation via locomotor activity of C57BL/6 mice. MethodsTo achieve this we built a nose-only inhalation device for pulmonary administration of nicotine to mice and determined the optimal operational parameters. We used the locomotor activity test to compare the effects of the inhaled nicotine hydrogen tartrate-loaded chitosan nanoparticles (NHT-CS) with NHT in C57BL/6 mice. The minimum inhaled dose of NHT-CS required to alter locomotor activity was compared with inhaled and subcutaneously (s.c) injected NHT. Finally, histological examination of lung tissues was performed to ensure inhalation of NHT-CS did not cause lung damage. ResultsWe found a flow rate of 0.9 L/min and an exposure time of 5 min achieved optimal delivery of nicotine. A minimum of 0.88 mg inhaled of NHT-CS or 0.59 mg inhaled of NHT was required to alter locomotor activity similarly to injection of 0.5 mg/kg nicotine, suggesting the reformulation process did not alter the activity of NHT-CS. No differences between untreated and NHT-CS treated lung tissue upon histological examination were observed. ConclusionsThe results indicated the inhaled NHT-CS is a viable preclinical option for developing novel inhalation formulations as a potential anti-smoking therapeutic.

Monosized Polymeric Microspheres Designed for Passive Lung Targeting: Biodistribution and Pharmacokinetics after Intravenous Administration.

Local as well as systemic therapy is often used to treat bacterial lung infections. Delivery of antibiotics to the vascular side of infected lung tissue using lung-targeting microspheres (MS) is a good alternative to conventional administration routes, allowing for localized high levels of antibiotics. This delivery route can also complement inhaled antibiotic therapy, especially in the case of compromised lung function. We prepared and characterized monodisperse poly(lactic-co-glycolic acid) (PLGA) MS loaded with levofloxacin using a flow-focusing glass microfluidic chip. In vitro characterization showed that the encapsulated LVX displayed a biphasic controlled release during 5 days and preserved its antibacterial activity. The MS degradation was investigated in vitro by cross-sectioning the MS using a focused ion beam scanning electron microscope and in vivo by histological examination of lung tissue from mice intravenously administered with the MS. The MS showed changes in the surface morphology and internal matrix, whereas the degradation in vivo was 3 times faster than that in vitro. No effect on the viability of endothelial and lung epithelial cells or hemolytic activity was observed. To evaluate the pharmacokinetics and biodistribution of the MS, complete quantitative imaging of the 111indium-labeled PLGA MS was performed in vivo with single-photon emission computed tomography imaging over 10 days. The PLGA MS distributed homogeneously in the lung capillaries. Overall, intravenous administration of 12 μm PLGA MS is suitable for passive lung targeting and pulmonary therapy.

Gubenzhike Recipe Ameliorates Respiratory Mucosal Immunity in Mice with Chronic Obstructive Pulmonary Disease through Upregulation of the γδT Lymphocytes and KGF Levels.

Background Gubenzhike recipe, a traditional Chinese herbal compound, was assumed to have a possible beneficial effect on COPD. This study was designed to elucidate the mechanism from the perspective of respiratory mucosal immunity. Methods COPD model was induced by exposure to cigarette smoke and LPS instillation in mice for 12 weeks. Animals were administered solution of Gubenzhike recipe by intragastric gavage daily for 4 weeks. After that, mice were sacrificed for lung function test and histological examination of lung tissues. The levels of IL-6 and IL-13 in serum, bronchoalveolar lavage fluid (BALF), and intestinal mucus were measured by ELISA. The KGF and KGFR in lung tissue were analysed by immunohistochemical staining, ELISA, and western blotting, and the mRNA expressions were assessed by PCR. γδT lymphocytes in the lungs were isolated and analysed by immunohistochemical staining and flow cytometry. Results Gubenzhike recipe improved the structure of airway and damage of lung tissue and also the respiratory status and lung function, reduced the content of IL-6 in serum and BALF and IL-13 in BALF and intestinal mucus, increased the proportion of γδT cells in lung tissue, and promoted the secretion of KGF and KGFR (P < 0.05). Conclusion We for the first time demonstrated an experimental procedure for the isolation of γδT lymphocytes from lung tissue. This study suggested that Gubenzhike recipe could enhance the respiratory mucosal immunity which provided experimental evidence for its effects of reinforcing “wei qi” by means of strengthening vital qi, tonifying spleen and kidney, relieving cough, and reducing phlegm in TCM.

Comparisons of antithrombosis, hematopoietic effects and chemical profiles of dried and rice wine-processed Rehmanniae Radix extracts

Ethnopharmacological relevanceIn traditional Chinese medicine (TCM), Rehmanniae Radix (RR, derived from the root of Rehmannia glutinosa (Gaertn.) DC.) is commonly used as natural medicine for thousands of years, two types including the dried and rice-wine processed RR were used for different clinical purposes respectively, which were the typical case that pharmaceutical effect changed by processing in TCM. Aim of studyThe goal of this study was to investigate the differences in the antithrombosis and hematopoietic effects of extracts of dried and processed RR (DRR and PRR) in vivo, and to explore the chemical basis underlying changes of medicinal properties caused by processing. Materials and methodsThe aqueous extracts of DRR and PRR were prepared. Protective effect of varying doses of different extracts were investigated in type-I carrageenan induced mice tail thrombosis and cyclophosphamide induced myelosuppression model. The chemical composition of DRR and PRR extracts were determined by High Performance Liquid Chromatography coupled with tandem quadrupole time-of-flight Mass Spectrometry (HPLC/Q-TOF-MS). ResultsIn antithrombosis activity tests, PRR possessed less ameliorated effects than DRR in the model mouse on body temperature, tail thrombus length and blood flow. Both DRR and PRR had no significant influence on prothrombin time (PT) and activated partial thromboplastin time (APTT), only high dose DRR could decrease the content of fibrinogen (FIB) in plasma. Histological examination of lung tissue suggested that thrombosis was significantly improved in DRR-H group. For myelosuppression model, only PRR could improve peripheral hemogram, both DRR and PRR had hematopoietic effects as demonstrated by their abilities to ameliorate the bone marrow nucleated cells (BMNC) and pathology of bone marrow tissue. The hematopoietic effects of PRR were significantly more potent than that of DRR at the concentration of 9 g/kg. By comparing the chemical composition, we found that iridoid glycosides were decreased and furfural derivatives increased in DRR after processing which may be the chemical mechanism contribute to the differences in efficacy. ConclusionsAccording to the results of this research, processing with rice wine for nine cycles significantly reduced antithrombotic effects and enhanced the hematopoietic effects of DRR as demonstrated in model mice. It can scientifically explain the different effect among two types of RR in clinical through the diverse method of processing and usage. Meanwhile, the predicted activity compounds from two types of RR can be potential candidates for the treatment of thrombosis and anemia.

Levocetirizine Pretreatment Mitigates Lipopolysaccharide-Induced Lung Inflammation in Rats.

This research was conducted to investigate possible protective influences of levocetirizine, a nonsedating H1 antihistamine, against lipopolysaccharide (LPS)-induced lung injury in rats. Male Sprague Dawley rats received either levocetirizine (1 mg/kg/day, orally) or the vehicle of the drug (2 ml/kg/day, orally) for 1 week before a single IP injection of LPS (7.5 mg/kg). A group of normal rats served as control. The experiments were terminated 18 h after the LPS challenge. Serum C-reactive protein levels were determined. Moreover, total cell count, lactate dehydrogenase (LDH) activity, protein levels, and total NOx were evaluated in bronchoalveolar lavage fluid (BALF). Pulmonary edema was evaluated as the wet/dry lung weight ratio. Lung tissue homogenate was assessed for antioxidant/pro-oxidant status. BALF and lung tissue levels of tumor necrosis factor-α (TNF-α) were assessed. Lungs were examined for histological alterations. LPS-mediated lung injury was manifested by pulmonary edema, leukocyte infiltration, oxidative stress, and inflammation. Levocetirizine attenuated lung edema and mitigated the increases in BALF protein levels, LDH activity, and lung leukocyte recruitment in LPS-challenged rats. Additionally, TNF-α protein levels in BALF and lung tissue were diminished by levocetirizine administration. Levocetirizine also exhibited a potent antioxidant activity as indicated by a decrease in lung tissue levels of malondialdehyde and an enhancement of superoxide dismutase activity. Histological examination of lung tissues confirmed the beneficial effect of levocetirizine against LPS-induced histopathological alterations. In conclusion, levocetirizine may offer protection against lung tissue damage and inflammation in LPS-challenged rats.

A rare case of streptomyces pulmonary infection with bronchopleural fistula

We report a rare fatal case of Streptomyces spp. intrathoracic infection causing a bronchopleural fistula in a 71-year-old man on long-term prednisone. A VATS decortication was performed, revealing a large pus-filled cavity. Histological examination of lung tissue revealed numerous sulfur granules with characteristic macroscopic and microscopic morphology. Branching Gram positive rods were seen on direct Gram stain. Cultures grew Streptomycyes spp. which was identified by MADI-TOF mass spectrometry and typical cultural and staining characteristics. Streptomyces genus identification was confirmed by 16S-rRNA and secA gene sequencing.

Protective efficacy of inhaled quercetin for radiation pneumonitis.

Radiation pneumonitis is a clinical problem with a high incidence. Once the onset of radiation pneumonitis has occurred, the administration of antioxidants and anti-inflammatory agents is the most commonly used method of clinical treatment. Quercetin (Que) is a common flavonoid, with potent anti-inflammatory and anti-oxidant activities. In the present study, the therapeutic effect of inhaled Que on radiation-induced radiation pneumonitis in rats was investigated. Treatment with Que via inhalation was shown to increase the number of leukocytes and erythrocytes in the blood, and reduce the number of inflammatory cells in bronchoalveolar lavage fluid. Histological examination of lung tissue indicated that inhaled Que reduced hemorrhaging and the infiltration of inflammatory cells, and suppressed the expression of the proinflammatory cytokines transforming growth factor-β1 and interleukin-6. These results indicated that treatment with Que via inhalation ameliorates radiation pneumonitis by reducing the number of inflammatory cells, and attenuating the inflammatory response and pathological changes. This suggests that administration of Que via inhalation has the potential to become a novel treatment for radiation pneumonitis.

No adverse lung effects of 7- and 28-day inhalation exposure of rats to emissions from petrodiesel fuel containing 20% rapeseed methyl esters (B20) with and without particulate filter – the FuelHealth project

Increased use of biofuels raises concerns about health effects of new emissions. We analyzed relative lung health effects, on Fisher 344 rats, of diesel engine exhausts emissions (DEE) from a Euro 5-classified diesel engine running on petrodiesel fuel containing 20% rapeseed methyl esters (B20) with and without diesel particulate filter (DPF). One group of animals was exposed to DEE for 7 days (6 h/day), and another group for 28 days (6 h/day, 5 days/week), both with and without DPF. The animals (n = 7/treatment) were exposed in whole body exposure chambers. Animals breathing clean air were used as controls. Genotoxic effects of the lungs by the Comet assay, histological examination of lung tissue, bronchoalveolar lavage fluid (BALF) markers of pulmonary injury, and mRNA markers of inflammation and oxidative stress were analyzed. Our results showed that a minor number of genes related to inflammation were slightly differently expressed in the exposed animals compared to control. Histological analysis also revealed only minor effects on inflammatory tissue markers in the lungs, and this was supported by flow cytometry and ELISA analysis of cytokines in BALF. No exposure-related indications of genotoxicity were observed. Overall, exposure to DEE with or without DPF technology produced no adverse effects in the endpoints analyzed in the rat lung tissue or the BALF. Overall, exposure to DEE from a modern Euro 5 light vehicle engine run on B20 fuel with or without DPF technology produced no adverse effects in the endpoints analyzed in the rat lung tissue or the BALF.

TOXICOLOGICAL AND HISTOLOGICAL EFFECTS OF SILVER NANOPARTICLES ON THE LUNG OF ADULT MALE ALBINO RAT AND PROTECTIVE ROLE OF GREEN TEA EXTRACT

Silver nanoparticles (AgNPs) are incorporated into a large number of consumer and medical products. AgNPs has been reported as the materials with high toxicity especially after the systemic uses. The present work aimed to evaluate the toxic effects of two different doses 0.5, 10 mg/kg of AgNPs (35±8.5nm) on the lung of adult male albino rat following 30 days oral administration and also to assess the protective role of green tea extract (GT). Sixty rats were classified into six groups (ten rats/ group); Group1:(control group) allowed distillate water, Group2: Rats were given GT at a concentration of 1.5%, Group3: AgNPs treated rats (0.5mg/kg/day), Group4: AgNPs treated rats (0.5mg/kg/day)–co administered GT, Group5: AgNPs treated rats (10mg/kg/day), and Group6: AgNPs (10mg/kg/ day)–co administered GT. This aim was undertaken through adopting certain parameters including, animal observation, changes in body weight, and biochemical studies for antioxidant enzymes {super oxide dismutase (SOD) and catalase (CAT)}. Absolute and relative lung weights have been carried as well. Histological examination of lung tissue using different stains; HE whereas a nonsignificant increase in GT group and groups treated with GT+ AgNPs at the end of experiment as compared to the initial value. AgNPs significantly decreased (CAT) while, increased SOD level. GT significantly increased relative lung weight while, a nonsignificant increase in AgNPs groups as compared to control. Histological examination of lung tissue revealed histological alterations in groups treated with AgNPs which were more pronounced in high dose (10mg) including; thickening of the alveolar wall, destruction of the alveoli, dilated alveoli, mononuclear cellular infiltration associated with marked collagen deposition and weak immunoexpression for surfactant protein B. Coadministration of GT with AgNPs caused significant amelioration of biochemical, histological and immunohistochemical changes induced by AgNPs. Conclusion: Silver nanoparticles caused oxidative damage, biochemical changes and histological alterations in the lung of male rat. This study demonstrates the benefits of green tea as it reduces oxidative damage by virtue of its antioxidant properties thus improving the structural integrity of lung tissue and eventually alleviates the histological changes as well as the biochemical perturbations.

CysLT2 receptor activation is involved in LTC4-induced lung air-trapping in guinea pigs

CysLT1 receptors are known to be involved in the pathogenesis of asthma. However, the functional roles of CysLT2 receptors in this condition have not been determined. The purpose of this study is to develop an experimental model of CysLT2 receptor-mediated LTC4-induced lung air-trapping in guinea pigs and use this model to clarify the mechanism underlying response to such trapping. Because LTC4 is rapidly converted to LTD4 by γ-glutamyltranspeptidase (γ-GTP) under physiological conditions, S-hexyl GSH was used as a γ-GTP inhibitor. In anesthetized artificially ventilated guinea pigs with no S-hexyl GSH treatment, i.v. LTC4-induced bronchoconstriction was almost completely inhibited by montelukast, a CysLT1 receptor antagonist, but not by BayCysLT2RA, a CysLT2 receptor antagonist. The inhibitory effect of montelukast was diminished by treatment with S-hexyl GSH, whereas the effect of BayCysLT2RA was enhanced with increasing dose of S-hexyl GSH. Macroscopic and histological examination of lung tissue isolated from LTC4-/S-hexyl-GSH-treated guinea pigs revealed air-trapping expansion, particularly at the alveolar site. Inhaled LTC4 in conscious guinea pigs treated with S-hexyl GSH increased both airway resistance and airway hyperinflation. On the other hand, LTC4-induced air-trapping was only partially suppressed by treatment with the bronchodilator salmeterol. Although montelukast inhibition of LTC4-induced air-trapping was weak, treatment with BayCysLT2RA resulted in complete suppression of this air-trapping. Furthermore, BayCysLT2RA completely suppressed LTC4-induced airway vascular hyperpermeability. In conclusion, we found in this study that CysLT2 receptors mediate LTC4-induced bronchoconstriction and air-trapping in S-hexyl GSH-treated guinea pigs. It is therefore believed that CysLT2 receptors contribute to asthmatic response involving air-trapping.

Effects of methylene blue in acute lung injury induced by oleic acid in rats.

In acute lung injury (ALI), rupture of the alveolar-capillary barrier determines the protein-rich fluid influx into alveolar spaces. Previous studies have reported that methylene blue (MB) attenuates such injuries. This investigation was carried out to study the MB effects in pulmonary capillary permeability. Wistar rats were divided into five groups: (I) Sham: saline bolus; (II) MB, MB infusion for 2 h; (III) oleic acid (OA), OA bolus; (IV) MB/OA, MB infusion for 2 h, and at 5 min after from the beginning, concurrently with an OA bolus; and (V) OA/MB, OA bolus, and after 2 h, MB infusion for 2 h. After 4 h, blood, bronchoalveolar lavage (BAL), and lung tissue were collected from all groups for analysis of plasma and tissue nitric oxide, calculation of the wet weight to dry weight ratio (WW/DW), and histological examination of lung tissue. Statistical analysis was performed using nonparametric test. Although favourable trends have been observed for permeability improvement parameters (WW/WD and protein), the results were not statistically significant. However, histological analysis of lung tissue showed reduced lesion areas in both pre- and post-treatment groups. The data collected using this experimental model was favourable only through macroscopic and histological analysis. These observations are valid for both MB infusions before or after induction of ALI.

A Post Mortem Case Study: Diffuse Pulmonary Ossification and Sudden Death

A post mortem examination was performed on a 45 year old white male who died suddenly during a competitive athletic swimming event. There were few clinical events seen in the year before his death. Clinical workup was negative and lung scan showed a small coin lesion was attributed to focal bacterial/fungal infection. Antibiotic treatment appeared to clear this condition on another follow up scan and he was sent home with an inhaler. On gross post mortem examination the lungs revealed diffuse pulmonary congestion, focal hemorrhage and edema. Small focal white areas of calcified lesions were also seen. In addition, an enlarged heart with left ventricular hypertrophy and thickened interventricular septum were seen. There was moderate atherosclerosis midway down the left anterior descending branch of the coronary artery observed. Histologic examination of lung tissue proved confirmatory for diffuse pulmonary ossification. Heart microscopic examination was consistent with cardiomyocyte hypertrophy. In conclusion, the diffuse pulmonary ossification was probably related to the sudden death with concomitant myocardial hypertrophy.