Rat Lung Parenchyma Research Articles

Evaluation of in vitro antioxidative and protective effects of kefir on cyclophosphamide-upon oxidative stress and lung damage in rats

Purpose: Kefir, a natural probiotic, has antioxidative and antitumor properties, as well as potential beneficial properties resulting from microbial species and fermentation. Cyclophosphamide (CYP) is a cytotoxic drug that is highly preferred in cancer therapy but can suppress both humoral and cellular immunity. The use of effective doses is limited because CYP has an immunosuppressive effect and causes multiple organ toxicity such as the lungs, and the use of effective high doses is restricted. Methods: Wistar albino rats were divided into 6 groups. As; control, 150 mg/kg CYP, 5 mg/kg kefir, 5 mg/kg kefir +150 CYP, l0 mg/kg kefir, l0 mg/kg kefir+150 CYP. Fermented kefirs from the 1st, 2nd and 3rd days were mixed and given to the rats for 12 days, while CYP was given as a single dose and ip on the 12th day of the experiment. The received parameters were evaluated. Results: It was observed that the OSI value, which indicates oxidative stress, increased in the CYP-administered group, and this level approached control in the CYP+kefir groups. In addition, while degeneration, intense inflammation in the interalveolar area, collapse of the alveoli, and intense inflammation around the bronchioles were observed in the lung parenchyma of CYP-administered rats, it was observed that these effects were effectively improved in the groups given kefir+CYP. Conclusion: In conclusion, in our study, it was observed that kefir showed antioxidative and protective effects on CYP-induced oxidative stress, congestion, alveolar damage and inflammation.

СТРУКТУРА БРОНХИАЛЬНЫХ АРТЕРИЙ КРЫС ПРИ ЧЕРЕПНО-МОЗГОВОЙ ТРАВМЕ И СИСТЕМНОМ ВОСПАЛЕНИИ

Purpose of the study: to present a histochemical and morphometric assessment of the state of the blood vessels of the bronchial tree and lung parenchyma of rats in experimental traumatic brain injury (TBI). and systemic inflammation caused by the administration of pyrogenal. Materials and methods. The experiment was carried out on mature male Wistar rats (200-250 g). Potentially painful interventions in the ongoing experiments and euthanasia were performed under combined injection anesthesia. The model of the falling weight modified by us for rats was used to reproduce TBI. To initiate systemic inflammation (SI), the animals were intramuscularly injected with pyrogenal solution. The study included the following groups: intact rats (n=12); after applying TBI (n=12)-TBI; triple administration (1, 3, 4 days) of pyrogenal without TBI (n=16)-SV; triple administration of pyrogenal (1, 3, 4 days) after TBI (n=12)-TBI+SV. On days 4 and 6 from the beginning of the experiment, under general anesthesia, the animals were dissected, their lungs were removed, after which histological sections were made. Morphological and functional changes in the blood vessels of the bronchial tree and lung parenchyma were analyzed in experimental traumatic brain injury (TBI) and systemic inflammation in rats. It has been established that in injured rats, the administration of pyrogenal has a significant effect on the structure of the bronchial blood vessels of the lungs, while the application of only TBI does not initiate such changes. At the same time, a significant change in the morphometric characteristics of blood vessels is detected, a spasm of arterioles is determined with a decrease in the diameter of the lumen on days 4 and 6 of the study, and an accumulation of segmented leukocytes, macrophages and other bronchial secretion cells in the perivascular space of the vessels is noted. Thus, the results of the study show that with the comorbidity of TBI and SI in the lungs, structural changes occur in the elastic framework of the distal bronchial arteries, which manifests itself changes in the structure of the elastic membranes of these blood vessels.

Toxic effect of carpet dust on the biochemical indices and histological structure of the lung in rats: the potential role of cytochrome P450 2E1 and extracellular signal-regulated kinase/mitogen-activated protein kinase pathways

Background: Carpet dust exposure in the carpet industry causes various respiratory hazards that lead to permanent loss of lung function. This study investigated the potentially toxic effects of knotted and tufted carpet dust on rat lungs and the possible involvement of cytochrome P450 2E1 (CYP2E1) and extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) pathways in the induced toxicity, as well as histological changes in the lung induced by carpet dust. Methods: This study divided 48 adult rats into six groups: group I was the control group, group II (vehicle group) received phosphate buffer saline (50 µL/rat), groups III and IV received knotted dust (2.5 and 5 mg/kg, respectively), and groups V and VI received tufted dust (2.5 and 5 mg/kg, respectively). All treatments were intranasally administered once a day for 7 days. Results: Both dust types significantly decreased the lung content of GSH compared with the control. Significantly elevated malondialdehyde (MDA) and nitric oxide (NO) lung contents were observed with an increased CYP2E1, interleukin (IL)-6, nuclear factor kappa B (NF-κβ), and ERK/MAPK. The histological lung structure was moderately affected with a moderately increased number of CD68-positive macrophages in the lung parenchyma of knotted dust-exposed rats, whereas tufted dust exposure severely affected the lung tissue with significantly increased CD68-positive macrophages. Conclusions: Carpet dust exposure could induce oxidative stress and inflammatory response in the lung tissue via induction of CYP2E1 that stimulates ERK/MAPK signalling pathway proteins, resulting in elevated MDA, NO and IL-6 levels in the lung tissue with suppressed GSH content. Tufted dust could possess a more toxic response than knotted ones.

ВЛИЯНИЕ СЕРПЕНТИНИТА НА БРОНХО-ЛЕГОЧНУЮ СИСТЕМУ КРЫС

Attempts to use serpentinite in agriculture as a soil ameliorant led to the need to study its effect on living organisms. For this, serpentinite from the Kabardino-Balkarian deposit was added to the food for Westar rats. Taking serpentinite led to inflammatory-destructive changes both in the bronchi and lung parenchyma of rats, as well as to the restructuring of blood vessels with the formation of hypertension in the pulmonary circulation. Khabaz serpentinite contains nickel salts. Perhaps nickel had a damaging effect on the broncho-pulmonary system of rats. For the sake of safety for living objects, it is necessary to clean the rock from nickel salts and continue research.

Unburned Tobacco Cigarette Smoke Alters Rat Ultrastructural Lung Airways and DNA.

Recently, the Food and Drug Administration authorized the marketing of IQOS Tobacco Heating System as a Modified Risk Tobacco Product based on an electronic heat-not-burn technology that purports to reduce the risk. Sprague-Dawley rats were exposed in a whole-body mode to IQOS aerosol for 4 weeks. We performed the chemical characterization of IQOS mainstream and we studied the ultrastructural changes in trachea and lung parenchyma of rats exposed to IQOS stick mainstream and tissue pro-inflammatory markers. We investigated the reactive oxygen species amount along with the markers of tissue and DNA oxidative damage. Moreover, we tested the putative genotoxicity of IQOS mainstream through Ames and alkaline Comet mutagenicity assays. Here, we identified irritating and carcinogenic compounds including aldehydes and polycyclic aromatic hydrocarbons in the IQOS mainstream as sign of incomplete combustion and degradation of tobacco, that lead to severe remodelling of smaller and largest rat airways. We demonstrated that IQOS mainstream induces lung enzymes that activate carcinogens, increases tissue reactive radical concentration; promotes oxidative DNA breaks and gene level DNA damage; and stimulates mitogen activated protein kinase pathway which is involved in the conventional tobacco smoke-induced cancer progression. Collectively, our findings reveal that IQOS causes grave lung damage and promotes factors that increase cancer risk. IQOS has been proposed as a safer alternative to conventional cigarettes, due to depressed concentration of various harmful constituents typical of traditional tobacco smoke. However, its lower health risks to consumers have yet to be determined. Our findings confirm that IQOS mainstream contains pyrolysis and thermogenic degradation by-products, the same harmful constituents of traditional cigarette smoke, and, for the first time, we show that it causes grave lung damage and promotes factors that increase cancer risk in the animal model.

Tryptase- and ghrelin positive mast cells in the interalveolar septa of rat’s lung

The mast cell mediators and distribution of lung mast cells in rats are often discussed in experimental studies on pulmonary fibrotic and allergic processes associated with changes in numbers of these cells, but information on the normal distribution of metachromatic and tryptase-positive mast cells in the interalveolar septa is scarce. There are no data on the presence of ghrelin in lung mast cells as well as the age-specific features of localisation and the number of mast cells in the interalveolar septa in rats of different ages. Therefore, the purpose of the present study was to determine the distribution of metachromatic, tryptase-, and ghrelin-positive mast cells in the interalveolar septa in 20 day-, 3 month- and 1 year-old rats. Tissue sections stained with toluidine blue had been taken from the left lung to visualise metachromasia and immunohistochemical expression of tryptase and ghrelin. The results showed that the amount of metachromatic mast cells in the interalveolar septa was significantly lower than that of tryptase- and ghrelin-positive cells. This allowed suggesting that mast cells were permanent occupants of the rat lung parenchyma and, on the other hand, the expression of ghrelin in their granules was most likely related to the synthesis of this protein. Our study showed that immunohistochemical identification by tryptase expression was more accurate than toluidine blue staining.

The effects of different ventilatory modes in female adult rats submitted to mechanical ventilation

This study aimed to analyze the effects of volume-controlled ventilation (VCV) and pressure-controlled ventilation (PCV) modes in female Wistar rats. 18 Wistar female adult rats were divided into three groups: control (CG), pressure-controlled ventilation (PCVG), and volume-controlled ventilation (VCVG). PCVG and VCVG were submitted to MV for one hour with a tidal volume (TV) of 8 mL/Kg, respiratory rate of 80 breaths/min, and positive end-expiratory pressure of 0 cmH2O. At the end of the experiment, all animals were euthanized. The neutrophils and lymphocytes influx to lung were higher in VCVG and PCVG compared to CG. The activities of superoxide dismutase, catalase and myeloperoxidase were higher in PCVG compared to CG. There was an increase in lipid peroxidation and protein oxidation in PCVG compared to CG. The levels of CCL3 and CCL5 were higher in PCVG compared to CG. In conclusions, the PCV mode promoted structural changes in the lung parenchyma, redox imbalance and inflammation in healthy adult female rats submitted to MV.

The Effects of High Fat Diet on Kidney and Lung Histopathology in Experimental Rats

High fat diet and obesity have been considered as a main risk factor for various diseases such heart disease, chronic kidney disease and respiratory diseases. However, the precise effect of high fat diet on lung and kidney histopathology is limited. The present study examined the effects of high fat diet on rat histopathology. Female albino Wistar rats of four-week-old were fed either a basic diet or a high-fat diet (20% of fat). After one month of feeding, the histopathological analysis of kidney and lung was investigated. The kidney tissue of rats fed with high-fat diet presented several alterations including variable size of glomeruli, bleeding and congested blood vessels and deformations of several tubular structures compared with those that fed a basic diet. While the lung parenchyma of rats fed with high fat diet showed collapsed alveoli separated by thick inter-alveolar septa, infiltration of inflammatory cells and congested blood vessels were also observed. In conclusion, the high fat diet is responsible for detectable changes in kidney and lung in female rat and this type of diet may lead to renal and respiratory deformities as a result of its histopathological effects.

A viscoelastic nonlinear compressible material model of lung parenchyma – Experiments and numerical identification

Characterizing material properties of lung parenchyma is essential in order to describe and predict the mechanical behavior of the lung in health and disease. Hence, we aim to identify the viscoelastic constitutive behavior of viable lung parenchyma with a particular focus on the nonlinear, compressible, and frequency-dependent material properties. To quantify the viscoelastic material behavior of rat lung parenchyma experimentally, we performed uniaxial tension tests with different frequencies, including the whole range of physiological frequencies, in combination with full-field displacement measurements (a total of 120 tests on 30 samples of 5 rats). By means of these experimental measurements, we identified the material parameters of two viscoelastic material models applicable to large three-dimensional deformations, i.e., the standard linear solid model and the model of fractional viscoelasticity. Our aim is to identify one set of material parameters that describes the whole range of physiological frequencies; therefore, we utilized a coupled inverse analysis, which equally incorporates all different tensile tests performed on one sample. The model most suitable for the description of the viscoelastic, nonlinear, and compressible material behavior of viable rat lung parenchyma is the strain energy function Ψ=356.7Pa(I1−3)+331.7Pa(I3−1.075−1)+71.05Pa(J−23I1−3)3+5.766Pa(I313−1)6 in combination with the model of fractional viscoelasticity (τ=0.06454s,α=0.5378, and β=1.856). This material model was validated to describe the complex nonlinear and compressible viscoelastic material behavior of lung parenchyma and can be utilized in finite element simulations of the whole range of physiological frequencies. Based on this model, it will be possible to quantify the stresses and strains of lung tissue during spontaneous and artificial breathing more reliable in the future.

Low power infrared laser modifies the morphology of lung affected with acute injury induced by sepsis

Acute lung injury (ALI) is a potentially fatal disease characterized by uncontrolled hyperinflammatory responses in the lungs as a consequence of sepsis. ALI is divided into two sequential and time-dependent phases, exudative and fibroproliferative phases, with increased permeability of the alveolar barrier, causing edema and inflammation. However, there are no specific treatments for ALI. Low-power lasers have been successfully used in the resolution of acute inflammatory processes. The aim of this study was to evaluate the effects of low-power infrared laser exposure on alveolus and interalveolar septa of Wistar rats affected by ALI-induced by sepsis. Laser fluences, power, and the emission mode were those used in clinical protocols for the treatment of acute inflammation. Adult male Wistar rats were randomized into six groups: control, 10 J cm−2, 20 J cm−2, ALI, ALI + 10 J cm−2, and ALI + 20 J cm−2. ALI was induced by intraperitoneal Escherichia coli lipopolysaccharide (LPS). Lungs were removed and processed for hematoxylin–eosin staining. Morphological alterations induced by LPS in lung tissue were quantified by morphometry with a 32-point cyclic arcs test system in Stepanizer. Data showed that exposure to low-power infrared laser in both fluences reduced the thickening of interalveolar septa in lungs affected by ALI, increasing the alveolar space; however, inflammatory infiltrate was still observed. Our research showed that exposure to low-power infrared laser improves the lung parenchyma in Wistar rats affected by ALI, which could be an alternative approach for treatment of inflammatory lung injuries.

High-intensity interval training-induced inflammation and airway narrowing of the lung parenchyma in male maturing rats

Besides the metabolic beneficial effects of high-intensity interval training (HIIT), it is able to increase the stress on lung parenchyma. This study examined 6 weeks of HIIT-induced inflammation and airway narrowing of the lung parenchyma in male maturing rats. All animals after 2 weeks of familiarization were divided in 3 groups of base (n = 10), HIIT (n = 10), and control (n = 10). HIIT was performed at speed of 20 m/min and ended at speed of 70 m/min (incrementally increase). Twenty-four hours after, the last training session animal was sacrificed and their lung removed. Lung samples were sectioned in 5 μm, stained with H&E, and studied histologically and histometrically. All these variables were measured at the end of exercise intervention. After 6 weeks of HIIT, measures of intima, media, and adventitia anatomical layers of the bronchi and bronchioles of the respiratory tract were significant than the control group (p = 0.05). Mechanical stress caused by excessive ventilation due to HIIT created histological inflammation in the bronchi and bronchioles of the respiratory tract. Thus, HIIT exercise causes reduction in the diameter of the lung parenchyma ducts that can affect the amount of oxygen consumption and consequently affect athletic performance.

Effects of emissions from sugar cane burning on the trachea and lungs of Wistar rats.

ABSTRACTObjective:To evaluate the effects of exposure to emissions from sugar cane burning on inflammatory mechanisms in tissues of the trachea and lung parenchyma in Wistar rats after different periods of exposure. Methods:This was an experimental open randomized study. The animals were divided into four groups: a control group (CG) underwent standard laboratory conditions, and three experimental groups were exposed to emissions from sugar cane burning over different periods of time, in days-1 (EG1), 7 (EG7), and 21 (EG21). After euthanasia with 200 mg/kg of ketamine/xylazine, fragments of trachea and lung were collected and fixed in 10% formalin. Histological analyses were performed with H&E and picrosirius red staining. Results:No inflammatory infiltrates were found in the tissues of CG rats. The histological examination of tissues of the trachea and lung parenchyma revealed that the inflammatory process was significantly more intense in EG7 than in the CG (p < 0.05 and p < 0.01, respectively). In comparison with the CG and EG1, angiogenesis in the lung parenchyma and collagen deposition in tracheal tissues were significantly greater only in EG21 (p < 0.001 and p < 0.01, respectively). Conclusions:In this sample, emissions from sugar cane burning induced acute focal and diffuse inflammation in the lamina propria of tracheal tissues, with no loss of ciliated epithelial tissue. In the lung parenchyma of the animals in the experimental groups, there was interstitial and alveolar edema, together with polymorphonuclear cell infiltrates.

Effects of aerobic exercise training on metabolism of nitric oxide and endothelin-1 in lung parenchyma of rats with pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is characterized by vasoconstriction and proliferative obstruction of pulmonary vessels, which promotes a progressive increase in pulmonary vascular resistance (PVR). The effect of exercise training on oxidative stress, metabolism, and markers of nitric oxide (NO) and endothelin-1 (ET-1) was analyzed in the lung tissue of rats with PAH induced by monocrotaline (MCT).Twenty-four Wistar rats were divided into four groups (5-7 animals): sedentary control (SC), sedentary MCT (SM), trained control (TC), and trained MCT (TM). The TC and TM groups participated in a treadmill training protocol (60% VO2 max) for 5weeks, 3weeks of which were performed after the injection of MCT (60mg/kg i.p.) or saline. MCT administration promoted an increase in PVR and right ventricle hypertrophy, and reduction of right ventricle systolic function assessed by echocardiography. These changes were not improved by exercise training. The activity of NO synthase was reduced in the animals of the TC, TM, and SM groups. No significant differences were found in total nitrite concentration and expression of endothelial NO synthase. Moreover, the TM group showed strong staining for iNOS and nitrotyrosine, suggesting an increase in oxidative stress in these animals. In parallel, reduced expression of type B ET-1 receptors was noticed in the SM and TM groups in comparison to controls. In conclusion, the aerobic training protocol was unable to mitigate changes in the metabolism of NO and ET-1, probably because of the disease severity in these animals, especially in the TM group.

Pulmonary perfusion quantification with flow-sensitive inversion recovery (FAIR) UTE MRI in small animal imaging.

Blood perfusion in lung parenchyma is an important property for assessing lung function. In small animals, its quantitation is limited even with radioactive isotopes or dynamic contrast-enhanced MRI techniques. In this study, the feasibility flow-sensitive alternating inversion recovery (FAIR) for the quantification of blood flow in lung parenchyma in free breathing rats at 7T has been investigated. In order to obtain sufficient signal from the short T2 * lung parenchyma, a 2D ultra-short echo time (UTE) Look-Locker read-out has been implemented. Acquisitions were segmented to maintain acquisition time within an acceptable range. A method to perform retrospective respiratory gating (DC-SG) has been applied to investigate the impact of respiratory movement. Reproducibilities within and between sessions were estimated, and the ability of FAIR-UTE to identify the decrease of lung perfusion under hyperoxic conditions was tested. The implemented technique allowed for the visualization of lung parenchyma with excellent SNR and no respiratory artifact even in ungated acquisitions. Lung parenchyma perfusion was obtained as 32.54±2.26mL/g/min in the left lung, and 34.09±2.75mL/g/min in the right lung. Application of retrospective gating significantly but minimally changes the perfusion values, implying that respiratory gating may not be necessary with this center-our acquisition method. A decrease of 10% in lung perfusion was found between normoxic and hyperoxic conditions, proving the feasibility of the FAIR-UTE approach to quantify lung perfusion changes.

Numerical identification method for the non-linear viscoelastic compressible behavior of soft tissue using uniaxial tensile tests and image registration – Application to rat lung parenchyma

This paper presents an improved identification method of the constitutive properties of lung parenchyma. We aim to determine the non-linear viscoelastic behavior of lung parenchyma with a particular focus on the compressible properties - i.e. the ability to change volume. Uniaxial tensile tests are performed on living precision-cut rat lung slices. Image registration is used to compute the displacement field at the surface of the sample. The constitutive model consists of a hyperelastic potential split into volumetric and isochoric contributions and a viscous contribution. This allows for the description of the experimentally observed hysteresis loop. The identification is performed numerically: each test is simulated using the realistic geometry of the sample; the difference between the measured and computed displacements is minimized with an optimization algorithm. We compare several hyperelastic potentials and we can determine the most suitable law for rat lung parenchyma. An exponential potential or a polynomial potential with a first order term and a third or higher order term give similarly satisfactory results. The identified parameters are: for the volumetric contribution: κ=7.25e4Pa, for the exponential form: k1=4.34e3Pa, k2=5.92, for the polynomial form: C1=2.87e3Pa, C3=3.83e4Pa. The identification of the time parameter for the viscous contribution shows that it depends on the loading frequency (0.2Hz: τ=0.257s, 0.4Hz: τ=0.123s, 0.8Hz: τ=0.050s). Adding a viscous contribution significantly increases the accuracy of the identification.

Role of Arginase in Impairing Relaxation of Lung Parenchyma of Hyperoxia-Exposed Neonatal Rats

Background: Prolonged exposure of immature lungs to hyperoxia contributes to neonatal lung injury and airway hyperreactivity. We have previously demonstrated that neonatal exposure of rat pups to ≧95% O₂ impairs airway relaxation due to disruption of nitric oxide (NO)-cyclic guanosine monophosphate (cGMP) signaling. Objective: We now hypothesize that these impaired relaxation responses are secondary to hyperoxia-induced upregulation of arginase, which competes with NO synthase for L-arginine. Methods: Rat pups were exposed to moderate neonatal hyperoxia (50% O₂) or room air for 7 days from birth. In additional hyperoxic and room air groups, exogenous L-arginine (300 mg/kg/day i.p.) or arginase inhibitor (Nω-hydroxy-nor-arginine, 30 mg/kg/day i.p.) were administered daily. After 7 days, animals were anesthetized and sacrificed either for preparation of lung parenchymal strips or lung perfusion. Results: In response to electrical field stimulation (EFS), bethanechol-preconstricted lung parenchymal strips from hyperoxic pups exhibited significantly reduced relaxation compared to room air controls. Supplementation of L-arginine or arginase blockade restored hyperoxia-induced impairment of relaxation. Expression of arginase I in airway epithelium was increased in response to hyperoxia but reduced by arginase blockade. Arginase activity was also significantly increased in hyperoxic lungs as compared to room air controls and reduced following arginase blockade. EFS-induced production of NO was decreased in hyperoxia-exposed airway smooth muscle and restored by arginase blockade. Conclusion: These data suggest that NO-cGMP signaling is disrupted in neonatal rat pups exposed to even moderate hyperoxia due to increased arginase activity and consequent decreased bioavailability of the substrate L-arginine. We speculate that supplementation of arginine and/or inhibition of arginase may be a useful therapeutic tool to prevent or treat neonatal lung injury.

Material model of lung parenchyma based on living precision-cut lung slice testing

We describe a novel constitutive model of lung parenchyma, which can be used for continuum mechanics based predictive simulations. To develop this model, we experimentally determined the nonlinear material behavior of rat lung parenchyma. This was achieved via uni-axial tension tests on living precision-cut rat lung slices. The resulting force–displacement curves were then used as inputs for an inverse analysis. The Levenberg–Marquardt algorithm was utilized to optimize the material parameters of combinations and recombinations of established strain–energy density functions (SEFs). Comparing the best-fits of the tested SEFs we found W p a r = 4.1 kPa ( I ¯ 1 − 3 ) 2 + 20.7 kPa ( I ¯ 1 − 3 ) 3 + 4.1 kPa ( − 2 ln J + J 2 − 1 ) to be the optimal constitutive model. This SEF consists of three summands: the first can be interpreted as the contribution of the elastin fibers and the ground substance, the second as the contribution of the collagen fibers while the third controls the volumetric change. The presented approach will help to model the behavior of the pulmonary parenchyma and to quantify the strains and stresses during ventilation.

DEHP effects on histology and cell proliferation in lung of newborn rats

Di-(2-ethylhexyl)-phthalate (DEHP), the plasticizer employed in the fabrication of polyvinyl chloride, is known to be released by many medical devices, namely endotracheal tubes currently utilised for pulmonary ventilation of pre-term newborns. When experimentally administered, especially to rodents, the phthalate reportedly causes alterations to several tissues, immature animals being even more responsive targets than adult ones. In the present research, female rats were fed with DEHP in the last week of pregnancy and after delivery, and lung of their pups was morphologically and immunohistochemically analysed. We detected significant alveolar simplification (larger but fewer alveoli with decreased septation), with consequent sensible reduction of gas-exchange surface, at several stages of postnatal development, in distal lung parenchyma of DEHP-treated rats. Moreover, the quantification of PCNA-expressing cells demonstrates that in treated pups the proliferation rates of epithelial and mesenchymal cells progressively increased during the first two postnatal weeks, at difference with controls animals, where the highest proliferation levels were reached at postnatal day 7. The obtained results strongly support the hypothesis that DEHP profoundly affects the alveolarization process in mammalian lung.

Novel immuno-spin trapping-based assay for the analysis of myeloperoxidase (100.13)

Abstract Myeloperoxidase (MPO) is an important biomarker of inflammatory diseases. The analyses of MPO in biological samples are based on detection of its peroxidase activity, chloramine formation, and MPO-capture immunoassays. We have developed an immuno-spin trapping (IST)-based approach to determine MPO in biological samples. In this approach, MPO/H2O2/Cl system produces hypochlorous acid (HOCl);HOCl reacts with proteins forming chloramines;chloramines decay forming protein radicals,protein radicals are trapped by the nitrone spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO) forming DMPO-protein nitrone adducts, andnitrone adducts are determined using a chemiluminescent direct ELISA with the anti-DMPO antiserum. We used this assay to quantify MPO in plasma, bronchoalveolar fluid and lung parenchyma of rats exposed to lipopolysaccharide, and compared its sensitivity with a capture-based commercial ELISA kit. Hemoglobin does not interfere and the assay can be used in animal and human samples. The assay has three levels of amplification: enzymatic formation of HOCl;many DMPO molecules bound per single protein molecule;a sensitive developing system. The IST-based assay for quantification of MPO will enhance the power of this biomarker for early detection of environmental- and metabolic-induced inflammatory disorders in both experimental and clinical settings. NIH#1K99 ES015414-01

Vitamin A deficiency alters pulmonary parenchymal collagen and tissue mechanics

The mechanical properties of the pulmonary parenchyma are strongly influenced by the collagen and elastic fibers that course through the alveolar interstitium and interconnect the bronchovascular bundles. Vitamin A deficiency (VAD) produces effacement and remodeling of the alveolar architecture, resulting in alternating areas of alveolar dilatation and collapse. To better understand the mechanical consequences and reversibility of this remodeling process, we have examined how the remodeling of collagen and elastic fibers correlates with the mechanical properties of the lung parenchyma in VAD rats. An oscillatory impulse was applied at different levels of stress on the fiber network and the tissue damping (G), elastance (H), hysteresivity (G/H, eta) were analyzed. At a supra-physiological functional residual capacity, the lung parenchyma of VAD rats exhibited a lower G and H than Vitamin A sufficient (VAS) rats, which was accompanied by a significant decrease in the quantity of parenchymal collagen and collagen fibers. Retinoic acid (RA) administration restored the parenchymal collagen and mechanical properties.