Mean Alveolar Number Research Articles

Simvastatin promotes alveolar epithelial cell proliferation and attenuates cigarette smoke‑induced emphysema in rats.

Current treatments for chronic obstructive pulmonary disease (COPD) cannot reverse the pathological process of the disease, therefore, the development of novel agents and strategies for COPD treatment is required. The aim of the present study was to investigate the potential therapeutic value of simvastatin (SmSt) in cigarette smoke‑induced emphysema in rats. A total of 24 male and female Wistar rats were randomly divided into four groups. The levels of vascular endothelial growth factor (VEGF) in the lung tissues and bronchoalveolar lavage (BAL) fluid of each group were measured using an enzyme‑linked immunoassay. The mRNA expression of VEGF was assessed using reverse transcription‑quantitative polymerase chain reaction. The protein expression levels of VEGF and proliferating cell nuclear antigen (PCNA) were determined using immunohistochemical assays. Histological scoring revealed that simvastatin reduced the total inflammatory scores significantly more in the simvastatin‑treated smoke‑exposed group, compared with the smoke exposed (Sm) group. Significant differences in the average inter‑alveolar septal wall distance and mean alveolar numbers were also observed between the SmSt and Sm groups. The levels of VEGF in the BAL fluid and lung tissue homogenates of the SmSt group were similar to those in the simvostatin‑only (St) and control (CtL) groups, and significantly higher compared with those in the Sm group. The expression of VEGF in the alveolar and bronchial epithelial cells of the SmSt group was similar to that in the CtL group, and significantly higher compared with that of the Sm group. The percentage of PCNA‑positive alveolar epithelial cells was significantly higher in the SmSt group compared with the Sm and CtL groups. Simvastatin exerted a significant impact on the expression of VEGF and attenuated cigarette smoke‑induced emphysema in rats. Therefore simvastatin may have beneficial effects in patients with COPD.

Bilirubin treatment suppresses pulmonary inflammation in a rat model of smoke-induced emphysema

BackgroundCigarette smoking is a significant risk factor for emphysema, which is characterized by airway inflammation and oxidative damage. ObjectivesTo assess the capacity of bilirubin to protect against smoke-induced emphysema. MethodsSmoking status and bilirubin levels were recorded in 58 patients with chronic obstructive pulmonary diseases (COPD) and 71 non-COPD participants. The impact of smoking on serum bilirubin levels and exogenous bilirubin (20 mg/kg/day) on pulmonary injury was assessed in a rat model of smoking-induced emphysema. At sacrifice lung histology, airway leukocyte accumulation and cytokine and chemokine levels in serum, bronchoalveolar lavage fluid (BALF) and lung were analyzed. Oxidative lipid damage and anti-oxidative components was assessed by measuring malondialdehyde, superoxide dismutase (SOD) activity and glutathione. ResultsTotal serum bilirubin levels were lower in smokers with or without COPD than non-smoking patients without COPD (P < 0.05). Indirect serum bilirubin levels were lower in COPD patients than patients without COPD (P < 0.05). In rats, cigarette smoke reduced serum total and indirect bilirubin levels. Administration of bilirubin reduced mean linear intercept and mean alveoli area, increased mean alveoli number, reduced macrophage, neutrophil and TNF-α content of BALF, and increased BALF and serum IL-10 level, but lowered local and systemic CCL2, CXCL2, CXCL8 and IL-17 levels. Bilirubin suppressed the smoke-induced systemic and regional oxidative lipid damage associated with increased SOD activity. ConclusionBilirubin attenuated smoking-induced pulmonary injury by suppressing inflammatory cell recruitment and pro-inflammatory cytokine secretion, increasing anti-inflammatory cytokine levels, and anti-oxidant SOD activity in a rat model of smoke-induced emphysema.

Effects and possible mechanisms of mesenchymal stem cell transplantation on emphysema in rats

To explore the effects of transplanting bone marrow mesenehymal stem cells (MSCs) on emphysema in rats and elucidate the possible mechanisms. A total of 24 female Sprague-Dawley rats were randomly divided randomly into 3 groups of control, emphysema and MSCs transplantation (n=8 each). The rat model of emphysema was established by 14-week exposure to cigarette smoking and then MSCs labeled with 4, 6-diamidino-2-phenylindole (DAPI) were injected into recipient rats of MSCs transplantation group via tail veins. At 2 and 4 weeks post-transplantation, engraftment and differentiation of MSCs was determined. At 8 weeks post-transplantation, lung fissure sections were prepared for examining the morphological alterations. The apoptosis of alveolar septal cells was assessed. And the levels of oxidative stress in sera and lung were detected. At 2 and 4 weeks post-transplantation, MSCs labeled with DAPI could be found in recipient lungs, some of which differentiated into type II alveolar epithelial cells. Mean linear intercept was higher in emphysema and MSCs transplantation groups than control group [(111 ± 23) and (90 ± 15) vs (74 ± 10) µm], mean alveolar numbers were lower than control group [(94 ± 22) and (125 ± 15) vs (159 ± 22)/mm²] (all P<0.05); mean linear intercept was higher and mean alveolar numbers were lower in emphysema group than MSCs transplantation group (both P<0.05). The apoptotic index of alveolar wall cells in emphysema group was higher than MSCs transplantation group [(13.5 ± 2.5)% vs (4.8 ± 0.7)%, P<0.05]. Malondialdehyde of sera and lung in emphysema and MSCs transplantation groups was higher than control group [(4.3 ± 0.8), (3.7 ± 0.4) vs (3.0 ± 0.4) nmol/ml, (5.4 ± 0.5), (4.8 ± 0.4) vs (4.2 ± 0.6) nmol/mg, all P<0.05]; malondialdehyde of sera and lung in emphysema group was higher than MSCs transplantation group (both P<0.05). Superoxide dismutase (SOD) of sera and lung in emphysema and MSCs transplantation groups was lower than control group [(8.7 ± 0.8), (9.6 ± 0.7) vs (10.5 ± 0.9) U/ml and (56.3 ± 13.4), (70.2 ± 11.0) vs (84.9 ± 13.0) U/mg, all P<0.05]; SOD of sera and lung in emphysema group was lower than MSCs transplantation group (both P<0.05). MSCs transplantation via tail vein may arrest the progression of emphysema in a cigarette-smoke-induced rat model of emphysema through a differentiation of injected MSCs into type II alveolar epithelial cells and down-regulations of apoptosis and oxidative stress.

PS-209 Bcg Vaccination Can Prevent Hyperoxic Lung Injury?

<h3>Introduction</h3> The aim of this study effects of BCG vaccine on the histopathologic and gene expression changes seen in hyperoxia induced neonatal rat lung injury. <h3>Method</h3> Twenty-three rat pubs were divided into four groups: air-exposed control group (n = 5), hyperoxia-exposed placebo group (n = 7), hyperoxia-exposed BCG-vaccinated group (n = 7), and air-exposed BCG-vaccinated group (n = 4). neonatal hyperoxic lung injury model was established according to the previous studies. Measurement of alveolar surface area, quantification of secondary crest formation, microvessel count, evaluation of alveolar septal fibrosis, and smooth muscle actin immunostaining were performed to assess hyperoxia-induced changes in lung morphology. The gene expression level was evaluated by RT-PCR. <h3>Results</h3> The alveolar surface areas were significant different between the oxygen exposed placebo group and oxygen exposed BCG vaccinated group (alveolar surface area; 0.29 ± 0.02 µm² and 0.52 ± 0.04 µm² p &lt; 0.05 respectively). Number of crests and microvessel count was found to be significantly increased in the oxygen exposed BCG vaccinated group compared with the animals in the oxygen exposed placebo group (p &lt; 0.05). Exposure to hyperoxia resulted in a significant decrease in mean alveolar surface area and number of crests formed compared with air-exposed animals (p &lt; 0.05). The degree of fibrosis was found to be significantly increased in the oxygen exposed placebo group compared with the animals in the oxygen exposed BCG vaccinated group (degree of fibrosis: 1.88 ± 0.33 and 0.91 ± 0.66 p &lt; 0.05 respectively). Immunostaining for SMA demonstrated hyperoxia-exposed animals with BCG vaccine in a significantly decrese in smooth muscle content compared with hyperoxia-exposed placebo animals (p &lt; 0.05). The expression of VEGF, FGF1, IL13, NFκB1 and TNFα in the lungs of vaccinated animals was significantly higher than that of non-vaccinated animals (p &lt; 0.05). <h3>Conclusion</h3> Our results suggest that BCG vaccination can be a new protective strategy against neonatal hyperoxic lung injury. These benefical effects may be interpreted with its immunomodulatory effects on proinflammatory-antiinflammatory cytocin balance and expression of growth factors.

Development and systematic oxidative stress of a rat model of chronic bronchitis and emphysema induced by biomass smoke

ABSTRACTBackground: Epidemiological research and meta-analyses of published data have shown that biomass smoke (BS) is a risk factor for chronic obstructive pulmonary disease (COPD). However, the link between BS and COPD lacks experimental confirmation. Objectives: To verify whether BS can induce pathologic changes and systemic oxidative stress, which may be relevant to the development of emphysema and chronic bronchitis in rats. Methods: Rats were exposed to BS, cigarette smoke (CS), or clean air (sham) for 14 weeks. During the exposure, the O2, SO2, and CO levels were monitored. Pathological changes in the lungs, systemic oxidative stress, and inflammation biomarkers, together with GSTM1 and GSTP1 mRNA expression in the lung were measured. The glutamate–cysteine ligase catalytic subunit (GCLC) protein expression in the lung was measured using immunohistochemistry and western blotting. Results: The O2, CO, and SO2 levels were 20.31 ± 0.03%, 981.72 ± 64.76, and 2.59 ± 0.26 mg/m3 for the BS group, respectively, while their levels in the CS group were 20.28 ± 0.15%, 745.56 ± 30.83, and 12.64 ± 0.591 mg/m3 respectively. As with the rats exposed to CS, the BS rats showed an increased number of inflammatory cells in the bronchoalveolar lavage fluid, an increased pulmonary mean linear intercept and a decreased pulmonary mean alveolar number. Characteristics of chronic bronchitis and peribronchial fibrosis were also found in the BS-exposed rat lungs. Reduced body weight, systemic oxidative stress, and increased GCLC protein expression in the lungs were observed in the rats exposed to BS and CS. Conclusions: BS can cause emphysema and chronic bronchitis similar to that caused by CS, which is accompanied by systemic oxidative stress and inflammation.

Establishment of rat chronic obstructive pulmonary disease model: a comparison between exposure to cigarette smoke alone and in combination with intra-tracheal injection of lipopolysaccharide

Objective To compare the efficacies of exposure to cigarette smoke alone and in combination with intra-tracheal injection of lipopolysaccharide in establishing rat models of chronic obstructive pulmonary disease(COPD).Methods A total of 24 8-week-old healthy Wistar rats were randomly divided into 2 model groups and a control group(Group C).The rat COPD models were established by two ways:intratracheal injection of lipopolysaccharide(LPS) twice + exposure to cigarette smoke for 1 month(Group A),and cigarette smoke inhalation for 80 days only(Group B).The pathologic characteristics of animal models,including the mean lining interval(MLI) and the mean alveoli number(MAN),were determined.The total and different white blood cell counts in bronchoalveolar lavage fluid(BALF) and blood samples were determined.Results The rats in the two model groups presented with cough or breathlessness periodically,and the white blood cell counts and neutrophil counts in the peripheral blood and BALF were significantly higher than those in the control group(P0.01).H-E staining showed that the lung tissues of rats in Group A and B had typical pathological features of COPD and emphysema.MLI were significantly higher and MAN were significantly lower in Group A and B than those in group C(both P0.01),but there was no statistical difference between the two model groups.Group A had more severe inflammatory response in the bronchial and lung tissues than Group B.And Group B was characterized by alveolar overdistension.Conclusion Both the two methods can successfully establish rat COPD model,with its pathophysiological changes similar to those of human COPD,with intra-tracheal injection of lipopolysaccharide being more consistent to the natural development of disease.

Apoptosis of alveolar wall cells in chronic obstructive pulmonary disease patients with pulmonary emphysema is involved in emphysematous changes

This study explored the role of apoptosis of alveolar wall cells of chronic obstructive pulmonary disease (COPD) patients with pulmonary emphysema in the pathogenesis of emphysema. The subjects were divided into three groups: COPD patients with pulmonary emphysema (COPD group), asymptomatic smokers and non-smokers. Lung tissues were harvested and histologically assessed. TUNEL assay was employed to determine the apoptotic cells. The expression of PCNA, Bax and SP-C in the lung alveolar wall cells were immunohistochemically determined. SP-C immunofluorescence staining was used to identify type II alveolar cells in the TUNEL-positive cells. The mean linear interval (MLI), mean alveoli number (MAN) and mean alveoli area (MAA) in COPD group were significantly different as compared with those in asymptomatic smokers and non-smokers, respectively (P<0.01). The proliferation index (PI), apoptosis index (AI) and the percentage of Bax-positive cells in COPD group were significantly greater than those of asymptomatic smokers and non-smokers (P<0.01). However, the percentage of SP-C-positive cells was significantly lower in COPD group than in asymptomatic smokers and non-smokers (P<0.01). Most of the TUNEL-positive cells expressed SP-C. In COPD group, the apoptosis of alveolar wall cells, especially apoptosis of type-II cells, may take part in the pathogenesis of emphysema. Up-regulation of Bax expression may be responsible for the apoptosis of alveolar wall cells in the COPD patients with pulmonary emphysema.

Inhibition of tumor necrosis factor-α reduces alveolar septal cell apoptosis in passive smoking rats

Recent studies have revealed that lung cell apoptosis plays an important role in pathogenesis of cigarette-induced chronic obstructive pulmonary disease (COPD). Tumor necrosis factor alpha (TNF-alpha) is one of the most important cytokines which are involved in COPD. This study aimed at investigating the influence of its inhibitor, recombinant human necrosis factor-alpha receptor II:IgG Fc fusion protein (rhTNFR:Fc) on alveolar septal cell apoptosis in passive smoking rats. Forty-eight rats were randomly divided into a normal control group, a passive smoking group, an rhTNFR:Fc intervention group and a sham intervention group. The passive smoking rats were treated by exposure to cigarette smoking daily for 80 days. After smoking for one month the rhTNFR:Fc intervention group was treated with rhTNFR:Fc by subcutaneous injection, the sham intervention group injected subcutaneously with a neutral preparation (normal saline 0.1 ml, manicol 0.8 ml, cane sugar 0.2 mg, Tris 0.024 mg as a control. Lung function was determined and the levels of TNF-alpha in serum and broncho-alveolar lavage fluid (BALF) were measured with enzyme-linked immunosorbnent assay (ELISA). Lung tissue sections stained by hematoxylin and eosin (HE) were observed for study of morphological alternations. Mean linear intercept (MLI) and mean alveolar numbers (MAN) were measured and the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) method was carried out to determine the percentage of positive cells and distribution of apoptotic cells. Increased MLI and decreased MAN were found in the passive smoking group compared with both the normal control group and the rhTNFR:Fc intervention group (P < 0.05). Forced expiratory volume in 0.3 second (FEV 0.3)/forced vital capacity (FVC) and peak expiratory flow (PEF) were lower in the passive smoking group than that in the normal control group (P < 0.05). Compared with the sham intervention group, FEV 0.3/FVC and PEF increased in the rhTNFR:Fc intervention group (P < 0.05). The levels of TNF-alpha in serum were higher in the passive smoking group than that in the normal control group (P < 0.05) and rhTNFR:Fc intervention group (P < 0.05). Significant differences were found between the levels of TNF-alpha in the serum of the rhTNFR:Fc intervention group and sham intervention group (P < 0.05). The levels of TNF-alpha in BALF were higher in the passive smoking group than that in the normal control group (P < 0.05), but no significant differences of TNF-alpha levels in BALF were found between the passive smoking group and rhTNFR:Fc intervention group. The number of TUNEL positive cells in alveolar septa was significantly increased in the passive smoking group as compared with the normal control group and the rhTNFR:Fc intervention group (P < 0.05). This study provides preliminary evidence that rhTNFR:Fc may interfere with TNF-alpha and reduce alveolar septal apoptosis in smoking rats.

Restoration of pathological changes of emphysema by angiogenesis factors:experiment of rats

To investigate whether intratracheal administration of basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) restore the pulmonary function and pathology in emphysema, and research the mechanism of they restored pulmonary emphysema, and the pathogenesis of pulmonary emphysema. Twenty-four Wistar rats were randomized into the 4 equal groups: bFGF group [receiving a single intratracheal instillation of porcine pancreatic elastase (PPE) 250 U/kg, and 4 weeks later receiving intratracheal instillation of bFGF 400 U once a week for 3 weeks), VEGF group (receiving a single intratracheal instillation of PPE 250 U/kg, and 4 weeks later receiving intratracheal instillation of VEGF 2 microg once a week for 3 weeks), control group [receiving a single intratracheal instillation of PPE 250 U/kg, and 4 weeks later receiving intratracheal instillation of normal saline (NS) once a week for 3 weeks], and normal group (receiving intratracheal instillation of NS in above-mentioned pattern). Four weeks after treatment, arterial blood sample was collected from the abdominal aorta to undergo blood gas analysis for assessment pulmonary function, and then the rata were killed with their lungs taken out to undergo pathological examination. Immunohistochemistry was performed to detect the CD34, markers of pulmonary capillary endothelial cells. There were no significant differences in the artery blood gas analysis among the four groups (all P > 0.05). The levels of mean alveoli number (MAN) of the bFGF and VEGF groups were (43 +/- 8)/HP and (44 +/- 9)/HP] respectively, both significantly higher than that of the control group [(30 +/- 6)/HP, both P < 0.01]. The levels of mean linear intercept (MLI) of the bFGF and VEGF groups were (196 +/- 38) microm and (194 +/- 38) microm respectively, both significantly lower than that of the control group [(288 +/- 68) microm, both P < 0.01). the mean alveoli area (MAA) level of the bFGF and VEGF groups were (9856 +/- 1864) microm(2) and (9804 +/- 1929) microm(2) respectively, both significantly lower than that of the control group [(14,525 +/- 3408) microm(2), both P < 0.01]. The percentages of CD34(+) cells of the bFGF and VEGF groups were (3.7 +/- 1.3)% and (2.6 +/- 1.2)% respectively, both significantly higher than that of the control group [(0.8 +/- 0.7)%, both P < 0.05). bFGF and VEGF can restore the pathological changes of experimental emphysema. The damage of pulmonary capillary may play an important role in the pathogenesis of pulmonary emphysema.

The Number of Alveoli in the Human Lung

The number of alveoli is a key structural determinant of lung architecture. A design-based stereologic approach was used for the direct and unbiased estimation of alveolar number in the human lung. The principle is based on two-dimensional topology in three-dimensional space and is free of assumptions on the shape, size, or spatial orientation of alveoli. Alveolar number is estimated by counting their openings at the level of the free septal edges, where they form a two-dimensional network. Mathematically, the Euler number of this network is estimated using physical disectors at a light microscopic level. In six adult human lungs, the mean alveolar number was 480 million (range: 274-790 million; coefficient of variation: 37%). Alveolar number was closely related to total lung volume, with larger lungs having considerably more alveoli. The mean size of a single alveolus was rather constant with 4.2 x 10(6) microm3 (range: 3.3-4.8 x 10(6) microm3; coefficient of variation: 10%), irrespective of the lung size. One cubic millimeter lung parenchyma would then contain around 170 alveoli. The method proved to be very efficient and easy to apply in practice. Future applications will show this approach to be an important addition to design-based stereologic methods for the quantitative analysis of lung structure.

Cardiopulmonary effects of granulocyte colony-stimulating factor in a canine model of bacterial sepsis

We investigated the effects of recombinant granulocyte colony-stimulating factor (G-CSF) in a canine model of septic shock. Awake 2-yr-old beagles were studied before and after intraperitoneal placement of an Escherichia coli-infected clot. Nine days before and until 3 days after clot placement, animals received daily high-dose (G-CSF (5 microgram/kg body wt; n = 17), low-dose G-CSF (0.1 microgram/kg body wt; n = 17), or a control protein (5 micrograms/kg body wt; n = 20). Survival rate was greater (P < 0.04, Wilcoxon test) in the high-dose G-CSF group (14/17) than in the low-dose G-CSF (10/17) and control (12/20) groups. High-dose G-CSF improved cardiovascular function, as evidenced by increased left ventricular ejection fraction (day 1 after clot; P < 0.001) and mean arterial pressure (day 2; P < 0.02) compared with low-dose G-CSF and control groups. High-dose G-CSF increased (P < 0.001) mean peripheral neutrophils before (-3 days) and after (2 h to 4 days) clot and produced a more rapid (P < 0.001) rise (day 2) and fall (day 4) in mean alveolar neutrophil numbers compared with the low-dose G-CSF and control groups. High-dose G-CSF decreased mean serum endotoxin (2-8 h; P < 0.002) and tumor necrosis factor (2 h; P < 0.02) levels and lowered blood bacteria counts (2-6 h; P < 0.04) compared with the low-dose G-CSF and control groups. Thus, in this canine model, G-CSF sufficient to increase peripheral neutrophils before and during peritonitis and septic shock enhances host defense, reduces cytokine (tumor necrosis factor) levels, and improves cardiovascular function and survival.