Objective: To determine whether tramadol has a protective effect against lung injury induced by skeletal muscle ischemia-reperfusion. Methods: Twenty Wistar male rats were allocated to one of two groups: ischemia-reperfusion (IR) and ischemia-reperfusion + tramadol (IR+T). The animals were anesthetized with intramuscular injections of ketamine and xylazine (50 mg/kg and 10 mg/kg, respectively). All of the animals underwent 2-h ischemia by occlusion of the femoral artery and 24-h reperfusion. Prior to the occlusion of the femoral artery, 250 IU heparin were administered via the jugular vein in order to prevent clotting. The rats in the IR+T group were treated with tramadol (20 mg/kg i.v.) immediately before reperfusion. After the reperfusion period, the animals were euthanized with pentobarbital (300 mg/kg i.p.), the lungs were carefully removed, and specimens were properly prepared for histopathological and biochemical studies. Results: Myeloperoxidase activity and nitric oxide levels were significantly higher in the IR group than in the IR+T group (p = 0.001 for both). Histological abnormalities, such as intra-alveolar edema, intra-alveolar hemorrhage, and neutrophil infiltration, were significantly more common in the IR group than in the IR+T group. Conclusions: On the basis of our histological and biochemical findings, we conclude that tramadol prevents lung tissue injury after skeletal muscle ischemia-reperfusion.

Keywords: Tramadol; Muscle, skeletal; Ischemic attack, transient; Lung Injury.

Objective: To investigate the effects of N-acetylcysteine (NAC) and pentoxifylline in a model of remote organ injury after hind-limb ischemia/reperfusion (I/R) in rats, the lungs being the remote organ system. Methods: Thirty-five male Wistar rats were assigned to one of five conditions (n = 7/group), as follows: sham operation (control group); hind-limb ischemia, induced by clamping the left femoral artery, for 2 h, followed by 24 h of reperfusion (I/R group); and hind-limb ischemia, as above, followed by intraperitoneal injection (prior to reperfusion) of 150 mg/kg of NAC (I/R+NAC group), 40 mg/kg of pentoxifylline (I/R+PTX group), or both (I/R+NAC+PTX group). At the end of the trial, lung tissues were removed for histological analysis and assessment of oxidative stress. Results: In comparison with the rats in the other groups, those in the I/R group showed lower superoxide dismutase activity and glutathione levels, together with higher malondialdehyde levels and lung injury scores (p < 0.05 for all). Interstitial inflammatory cell infiltration of the lungs was also markedly greater in the I/R group than in the other groups. In addition, I/R group rats showed various signs of interstitial edema and hemorrhage. In the I/R+NAC, I/R+PTX, and I/R+NAC+PTX groups, superoxide dismutase activity, glutathione levels, malondialdehyde levels, and lung injury scores were preserved (p < 0.05 for all). The differences between the administration of NAC or pentoxifylline alone and the administration of the two together were not significant for any of those parameters (p > 0.05 for all). Conclusions: Our results suggest that NAC and pentoxifylline both protect lung tissue from the effects of skeletal muscle I/R. However, their combined use does not appear to increase the level of that protection.

Keywords: Skeletal muscle; Ischemia; Reperfusion injury; Lung injury; Acetylcysteine; Pentoxifylline.

Objective: To evaluate the effects that administering dexamethasone before the induction of ventilator-induced lung injury (VILI) has on the temporal evolution of that injury. Methods: Wistar rats were allocated to one of three groups: pre-VILI administration of dexamethasone (dexamethasone group); pre-VILI administration of saline (control group); or ventilation only (sham group). The VILI was induced by ventilation at a high tidal volume. Animals in the dexamethasone and control groups were euthanized at 0, 4, 24, and 168 h after VILI induction. We analyzed arterial blood gases, lung edema, cell counts (total and differential) in the BAL fluid, and lung histology. Results: At 0, 4, and 24 h after VILI induction, acute lung injury (ALI) scores were higher in the control group than in the sham group (p < 0.05). Administration of dexamethasone prior to VILI induction decreased the severity of the lung injury. At 4 h and 24 h after induction, the ALI score in the dexamethasone group was not significantly different from that observed for the sham group and was lower than that observed for the control group (p < 0.05). Neutrophil counts in BAL fluid were increased in the control and dexamethasone groups, peaking at 4 h after VILI induction (p < 0.05). However, the neutrophil counts were lower in the dexamethasone group than in the control group at 4 h and 24 h after induction (p < 0.05). Pre-treatment with dexamethasone also prevented the post-induction oxygenation impairment seen in the control group. Conclusions: Administration of dexamethasone prior to VILI induction attenuates the effects of the injury in Wistar rats. The molecular mechanisms of such injury and the possible clinical role of corticosteroids in VILI have yet to be elucidated.

Keywords: Ventilator-induced lung injury; Dexamethasone; Respiratory distress syndrome, adult.

Objetivo: Investigar os efeitos agudos da administração endovenosa de extrato da fumaça do cigarro (EFC) em parâmetros funcionais respiratórios, inflamatórios e histológicos em ratos e comparar esse potencial modelo de lesão pulmonar aguda (LPA) com aquele com o uso de ácido oleico (AO). Métodos: Foram estudados 72 ratos Wistar machos divididos em quatro grupos: tratados somente com soro fisiológico (SF; grupo controle); tratados com EFC e SF (grupo EFC); tratados com SF e AO (grupo AO); e tratados com EFC e AO (grupo EFC/AO). Resultados: As médias de complacência foram significantemente menores nos grupos AO e EFC/AO (2,12 ± 1,13 mL/cmH2O e 1,82 ± 0,77 mL/cmH2O, respectivamente) do que no controle (3,67 ± 1,38 mL/cmH2O). A proporção de neutrófilos e a atividade das metaloproteinases 2 e 9 em lavado broncoalveolar foram significantemente maiores nos grupos AO e EFC/AO que no controle. O acometimento pulmonar avaliado por morfometria foi significantemente maior nos grupos AO e EFC/AO (72,9 ± 13,8% e 77,6 ± 18,0%, respectivamente) do que nos grupos controle e EFC (8,7 ± 4,1% e 32,7 ± 13,1%, respectivamente), e esse acometimento foi significantemente maior no grupo EFC que no grupo controle. Conclusões: A administração endovenosa de EFC, nas doses e tempos deste estudo, associou-se à LPA mínima. O EFC não potencializou a LPA induzida por AO. Estudos adicionais são necessários para esclarecer o papel potencial desse modelo como método de estudo dos mecanismos de agressão pulmonar pelo tabaco.

Keywords: Tabagismo; Lesão pulmonar aguda; Modelos animais.

Objetivo: Avaliar o dano oxidativo (oxidação lipídica, oxidação proteica, thiobarbituric acid-reactive substances [TBARS, substâncias reativas ao ácido tiobarbitúrico], e carbonilação) e inflamação (expressão de phosphorylated AMP-activated protein kinase e de phosphorylated mammalian target of rapamycin (p-AMPK e p-mTOR, respectivamente) em tecido pulmonar e músculos do diafragma em camundongos C57BL/6 machos expostos à fumaça de cigarro (FC) por 7, 15, 30, 45 ou 60 dias. Métodos: Trinta e seis camundongos machos da espécie C57BL/6 foram divididos em seis grupos (n = 6/grupo): grupo controle e 5 grupos expostos a FC por 7, 15, 30, 45 e 60 dias, respectivamente. Resultados: Comparados aos camundongos controle, os camundongos expostos à FC apresentaram menor peso corporal em 30 dias. Nos camundongos expostos à FC (comparados aos controle) as maiores diferenças (aumentos) nos níveis de TBARS foram observados no dia 7 no músculo diafragma, comparado ao dia 45 em tecido pulmonar; as maiores diferenças (aumentos) nos níveis de carbonilas foram observados no dia 7 em ambos os tipos de tecido; e os níveis de sulfidrilas foram menores, nos dois tipos de tecidos, em todos os tempos. No tecido pulmonar e no músculo diafragma, a expressão de p-AMPK exibiu um comportamento semelhante ao dos níveis de TBARS. A expressão de p-mTOR foi maior que o valor controle nos dias 7 e 15 no tecido pulmonar, assim como no dia 45 no músculo diafragma. Conclusões: Nossos dados demonstram que a exposição à FC produz dano oxidativo tanto no tecido pulmonar quanto (primariamente) no tecido muscular, tendo um efeito adicional no músculo respiratório, como é frequentemente observado em fumantes com DPOC.

Keywords: Oxidative stress; Mice; Respiratory system; Smoking; Inflammation.

Objective: To investigate the effects of quercetin in a model of bleomycin-induced pulmonary inflammation and fibrosis. Methods: Seventynine adult male hamsters were randomized to receive intratracheal (IT) instillations and intraperitoneal (IP) injections in four configurations: IP vehicle/IT saline (VS group, n = 16); IP quercetin/IT saline (QS group, n = 16); IP vehicle/IT bleomycin (VB group, n = 27); and IP quercetin/ IT bleomycin (QB group, n = 20). Quercetin and bleomycin were administered at 30 mg/kg/day and 10 U/kg, respectively. Quercetin was started/discontinued 3 days before/14 days after the IT instillations. Results: The mortality rate was significantly higher in the VB group than in the other groups (44% vs. VS: 0%; QS: 0%; and QB: 15%). Lung levels of thiobarbituric acid reactive substances (× 10−2 nmol/mg) were significantly higher in the VB group (6.6 ± 1.3 vs. VS: 5.5 ± 0.8; QS: 2.5 ± 0.6; and QB: 5.8 ± 0.6). Lung levels of reduced glutathione (× 10−2 nmol/mg) were significantly lower in the VB/QB groups than in the VS/QS groups (28.9 ± 13.8/28.6 ± 14.8 vs. 43.9 ± 16.0/51.1 ± 20.3), whereas those of hydroxyproline (mg/g) were significantly higher (201.6 ± 37.3/177.6 ± 20.3 vs. 109.6 ± 26.1/117.5 ± 32.0).Mean lung septal thickness (μm) was greatest in the VB group (16.9 ± 3.2 vs. VS: 3.0 ± 0.3; QS: 3.3 ± 0.2; and QB: 5.2 ± 1.1). Conclusions: In a hamster model of lung injury, quercetin exhibited anti-inflammatory effects that are related, at least in part, to its antioxidant properties.

Keywords: Pulmonary fibrosis; Bleomycin; Flavonoids; Lipid peroxidation.

Objective: Brain death (BD) triggers important hemodynamic and inflammatory alterations, compromising the viability of organs suitable for transplantation. To better understand the mi-crocirculatory alterations in donor lungs caused by BD. The present study investigated the pul-monary microcirculation in a rodent model of BD via intravital microscopy. Methods: Male Wistar rats were anaesthetized and mechanically ventilated. They were trepanned and BD was induced through the increase in intracranial pressure. As control group, sham-operated (SH) rats were trepanned only. In both groups, expiratory O2 and CO2 were monitored and after three hours, a thoracotomy was performed, and a window was created to observe the lung surface using an epi-fluorescence intravital microscopy. Lung expression of intercellular adhesion molecule (ICAM)-1 and endothelial nitric oxide synthase (eNOS) was evaluated by immunohistochemistry, and cytokines were measured in lung samples. Results: Three hours after the surgical proce-dures, pulmonary perfusion was 73% in the SH group. On the other hand, BD animals showed an important decrease in organ perfusion to 28% (p = 0.036). Lung microcirculatory compromise after BD induction was associated with an augmentation of the number of leukocytes recruited to lung tissue, and with a reduction in eNOS expression and an increase in ICAM-1 expression on lung endothelial cells. BD rats showed higher values of expiratory O2 and lower values of CO2 in comparison with SH animals after three hours of monitoring. Conclusion: Data presented showed that BD triggers an important hypoperfusion and inflammation in the lungs, compromis-ing the donor pulmonary microcirculation

Keywords: Brain death; Inflammation; Intravital microscopy; Lung microcirculation.

Introduction: Surgical procedures requiring aortic occlusion have been associated with pulmonary reperfusion injury. The authors studied the pulmonary edema in a reperfusion injury model by aortic occlusion in rats. Material and methods: Thirty-three Wistar rats were anesthetized with intraperitoneal injection of sodium pentobarbital (20 mg/kg). Using a midline abdominal incision, the infra-renal aorta was isolated and the animals were randomized into three groups. Ischemia-reperfusion group (IRG, n = 5): rats that underwent 30 min of aorta occlusion and were followed during 120 min of reperfusion. Ischemia group (IG, n = 5): rats that underwent 30 min of aorta occlusion. Control group (CG, n = 5): rats that underwent sham operations without aorta occlusion and were followed during 150 min. Histopathologic examination of the right lung was performed. The pulmonary edema was studied by morphometric analysis and so was the leukocytes infiltration. Eighteen rats (6 rats in each group) were studied with respect to lung fresh/dry weight ratio. ANOVA was used to analyze the morphometric results and the lung fresh/dry weight ratio, with Bonferroni adjustment for paired multiple comparisons. Animals of the IRG presented more pulmonary edema than those of the IG and CG (0.24 vs. 0.17 and 0.17, p < 0.001). There was no difference between the groups regarding the lung fresh/dry weight ratio. There were more inflammatory cells in the lungs of the rats submitted to ischemia-reperfusion. The authors concluded that infra-renal abdominal aorta cross-clamping and unclamping are associated with pulmonary edema. This edema is not induced by elevation of the hydrostatic pressure due to the aortic occlusion, since it was not seen in animals that were only submitted to ischemia.

Keywords: ischemia, reperfusion, pulmonary edema, inbred strains rats

Introduction: Most of the experimental studies on amiodarone-induced pulmonary toxicity have been performed in male Fischer-344 rats. Objective: To investigate the effect of amiodarone on body weight and on lung morphological and cytopathologic parameters in both genders of other rat strains. Methods: Groups of male and female Wistar, Wistar-Kyoto (WKY) and spontaneously hypertensive (SHR) rats received, 175 mg/kg/day of amiodarone suspended in saline by gavage for four weeks. Controls received saline alone. Body weight gain, total cellularity, and differential of the bronchoalveolar lavage (BAL) and lung histopathology were studied. Results: Mortality due to amiodarone was observed in treated WKY rats, mostly in males. Treated male and female SHR animals had less body weight gain among all strains studied. Male Wistar and SHR treated rats presented more body weight gain than females of the respective strains. BAL of treated SHR rats were hemorrhagic. BAL cellularity was higher in treated males (WKY > Wistar > SHR). In WKY males and females, however, the differential count showed a lesser percent of macrophages and higher of neutrophils than in the other strains. BAL macrophages of treated Wistar rats presented phospholipidosis, whereas most macrophages of treated SHR rats were normal. In lung anatomicopathologic examination, no difference was found related to gender and no pneumonitis was observed. In Wistar rats, the examination was characterized by a marked quantity of intra-alveolar "foamy" macrophages, numerous intraparenchymal abscesses were found in WKY rats, and alveolar hemorrhage was present in SHR rats. Conclusions: 1) amiodarone induces more foamy macrophages in Wistar rats than in the WKY and SHR strains, although they do not develop pneumonitis in the model used; 2) amiodarone has greater effect on lung morphological and cytopathologic parameters of male rats.

Objective: To compare the influence of two different ventilation strategies-volume-controlled ventilation (VCV) and pressure-controlled ventilation (PCV)-on the functional performance of lung grafts in a canine model of unilateral left lung transplantation using donor lungs harvested after three hours of normothermic cardiocirculatory arrest under mechanical ventilation. Methods: The study comprised 40 mongrel dogs, randomized into two groups: VCV and PCV. Of the 20 recipients, 5 did not survive the transplant, and 5 died before the end of the post-transplant assessment period. The remaining 10 survivors (5 in each group) were evaluated for 360 min after lung transplantation. The functional performance of the grafts was evaluated regarding respiratory mechanics, gas exchange, and lung graft histology. Results: There were no significant differences between the groups regarding respiratory mechanics (peak inspiratory pressure, plateau pressure, mean airway pressure, dynamic compliance, and static compliance) or gas exchange variables (PaO2, venous oxygen tension, PaCO2, venous carbon dioxide tension, and the arterial-venous oxygen content difference). The histopathological findings were consistent with nonspecific acute lung injury and did not differ between the groups. Conclusions: This model of lung transplantation showed that the functional performance of lung grafts was not influenced by the ventilation strategy employed during the first six hours after reperfusion.

Keywords: Pulmonary ventilation; Respiration, artificial; Lung transplantation; Dogs; Organ preservation.

Objective: To evaluate the effects of immunization with a DNA-hsp65 vaccine in an experimental model of pulmonary fibrosis. Methods: A total of 120 male C57BL/6 mice were distributed into four groups: SS, injected with saline (placebo) and then receiving intratracheal (IT) instillation of saline; SB, injected with saline (placebo) and then receiving IT instillation of bleomycin; PB, treated with plasmid only, without bacterial genome, and then receiving IT instillation of bleomycin; and BB, treated with the vaccine and then receiving IT instillation of bleomycin. Bleomycin was instilled 15 days after the last immunization, and the animals were killed six weeks thereafter. The left and right lungs were removed, the former for morphological analysis and the latter for hydroxyproline measurements. Results: The proportion of deaths within the first 48 h after the IT instillation (deaths attributed to the surgical procedure) was higher in the SB group than in the SS group (57.7% vs. 11.1%). The mean area of pulmonary interstitial septa was greater in the SB and PB groups (53.1 ± 8.6% and 53.6 ± 9.3%, respectively) than in the SS and BB groups (32.9 ± 2.7% and 34.3 ± 6.1%, respectively). The mean area of interstitial septa stained by picrosirius was greater in the SB, PB and BB groups than in the SS group (8.2 ± 4.9%, 7.2 ± 4.2% and 6.6 ± 4.1%, respectively, vs. 2.0 ± 1.4%). The total hydroxyproline content in the lung was significantly lower in the SS group (104.9 ± 20.9 pg/lung) than in the other groups (SB: 160.4 ± 47.8 pg/lung; PB: 170.0 ± 72.0 pg/lung; and BB: 162.5 ± 39.7 pg/lung). Conclusions: Immunization with the DNA-hsp65 vaccine reduced the deposition of noncollagen matrix in a model of bleomycin-induced lung lesion.

Keywords: Pulmonary fibrosis; Bleomycin; Collagen.

Objective: To evaluate the effect that respiratory muscle stretching using the global postural reeducation (GPR) method has on respiratory muscle strength, thoracic expansion and abdominal mobility in sedentary young males. Methods: This was a randomized study involving 20 sedentary volunteers, aged 22.7 ± 2.5 years, divided into two groups of 10: a control group, composed of subjects not performing any exercises, and a group of subjects submitted to the GPR method. The protocol consisted of a program to stretch the respiratory muscles with participants in the 'open-arm, open hip joint angle' position, which was regularly performed twice a week for 8 weeks, totaling 16 sessions. The two groups were submitted to measurements of maximal inspiratory pressure, maximal expiratory pressure, thoracic expansion and abdominal mobility, prior to and after the intervention period. Results: The initial and final values for maximal respiratory pressures, thoracic expansion and abdominal mobility for the control group showed no significant differences (p > 0.05). However, for the GPR group, all values increased after the intervention (p < 0.05). Conclusions: Respiratory muscle stretching using the GPR method was efficient in promoting an increase in maximal respiratory pressures, thoracic expansion and abdominal mobility, suggesting that it could be used as a physiotherapy resource to develop respiratory muscle strength, thoracic expansion and abdominal mobility.

Keywords: Posture; Muscle Strength; Respiratory Muscles; Muscle Stretching Exercises.

Objective: To describe the development of a silicone stent and perform in vivo testing for biocompatibility/applicability in the normal canine trachea. Methods: Four different densities were tested in order to obtain the silicone prototypes. The pressure required for compression considering a contact area of 1 cm2, and a 30% reduction in diameter was calculated for each density. The best density was 70-75 Shore A hardness. Powdered barium sulfate was added to the silicone to make the stent radiopaque and easily identifiable in radiological imaging. This novel stent presents a corrugated external surface with discontinuous and protruding arcs resembling the tracheobronchial rings (for intercalation and fixation in the lumen of the lower airways), a highly polished inner surface and smooth extremities (to prevent friction-related damage). The prototype considered most appropriate in terms of rigidity and flexibility was bronchoscopically implanted in normal canine tracheas. After eight weeks, the animals were euthanized, and the tracheas were removed for anatomopathological analysis. Results: There were no postimplantation complications, and none had to be removed. After eight weeks, the devices were found to be well-positioned. Histopathology revealed a well-preserved epithelial basal membrane, foci of denuded epithelium, mild submucosal inflammatory infiltrate with scattered granulation tissue, vascular neoformation, and no microorganisms. Conclusions: The stent developed proved resistant to mechanical stress, biocompatible in the canine trachea and well-preserved at the study endpoint.

Keywords: Implants, experimental; Silicones; Biocompatible materials.

We aimed to test a new model of self-expanding tracheal stent so that it might be made available for clinical use. Using direct laryngoscopy, we placed polyurethane-coated, nitinol stents into the middle third of the trachea in 25 New Zealand rabbits. After a mean observation period of 26 days, we evaluated stent migration, degree of expansion, attachment, adherence, formation of granulation tissue, presence of inflammatory infiltrate, parietal involvement, and epithelial lining. The results showed complete radial expansion, little adherence to the tracheal mucosa, and low tissue attachment, as well as high rates of granuloma formation and stent migration. This new model proved to be biocompatible and showed a behavior similar to that of other stents on the market.

Keywords: Prosthesis implantation; Tracheal stenosis; Rabbits; Stents.

Background: Lung volume reduction surgery may be a viable treatment alternative for emphysema patients suffering from severe respiratory insufficiency. Objectives: To evaluate functional and morphological aspects of emphysematous rat lungs, prior to and following lung volume reduction surgery. Method: Wistar rats were divided into two experimental groups (papain without surgery and papain with surgery) and three control groups (saline without surgery, saline with surgery and papain without mechanical ventilation). After approximately 40 days of endotracheal instillation of papain or saline solution, animals in the papain with surgery and saline with surgery groups were submitted to bilobectomy of the middle lobes by right thoracotomy along the posterior border of the superior vena cava. After 1 week, the same animals were submitted to a mechanical ventilation study, which involved measurement of lung elasticity and airway resistance. For all of the animals studied, lung tissue was analyzed in order to determine alveolar diameter and the elastic fiber quantity. Results: Morphometric analysis revealed higher mean alveolar diameter in the lungs of all animals exposed to papain as compared to those exposed to saline. Elastic fiber counts in the alveolar septa of animals treated with papain were lower than those of animals receiving saline. In the animals submitted to bilobectomy and papain, lung elasticity was greater than in those receiving papain without surgery and was statistically equal to that seen in animals receiving saline (with or without surgery). Conclusion: In the respiratory systems of animals with pulmonary emphysema submitted to lung volume reduction by bilobectomy, the capacity for elastic recoil returned to values equivalent to those of the control group animals.

Keywords: Key words: Pulmonary emphysema. Papain/drugs efects. Case-control studies. Disease models, animal. Respiratory mechanics/drugs efects. Lung/sugery. Lung/anatomy & histology.

Objective: Although Mycobacterium avium complex (MAC) lung disease has been shown to be associated with lung cancer and hematologic malignancies, there have been few studies of its relationships with other types of cancer. The aim of this study was to assess the effect that coexisting advanced extrapulmonary solid tumors have on the progression of MAC lung disease. Methods: This was a retrospective study of patients diagnosed with MAC lung disease, on the basis of the American Thoracic Society (ATS) criteria, between October of 2005 and March of 2019. The patients were divided into three groups: those with advanced-stage cancer (A-SC group); those with early-stage cancer (E-SC group); and those without cancer (control group). Progression of MAC lung disease was defined as exacerbation seen on imaging. Patient characteristics and the time to progression were compared among the three groups. Results: A total of 286 patients met the ATS diagnostic criteria for MAC lung disease, and 128 of those were excluded. Of the remaining 158 patients, 20 (7.0%) were in the A-SC group, 36 (12.6%) were in the E-SC group, and 102 (35.7%) were in the control group. The median time to progression in the A-SC, E-SC, and control groups was 432, 3,595, and 2,829 days, respectively (p < 0.01). A proportional hazards model showed that the significant predictors of MAC lung disease progression were advanced-stage cancer (hazard ratio [HR] = 6.096; 95% CI: 2.688-13.826; p < 0.01), cavitary lesions (HR = 2.750; 95% CI: 1.306-5.791; p < 0.01), and a high Nodule-Infiltration-Cavity-Ectasis score (HR = 1.046; 95% CI: 1.004-1.091; p = 0.033). Conclusions: A coexisting advanced extrapulmonary solid tumor could hasten the progression of MAC lung disease.

Keywords: Nontuberculous mycobacteria; Mycobacterium avium complex; Neoplasms; Radiography.