Background: Short-acting b2 agonists delivered by metered-dose inhaler (MDIs) are the drugs usually used for the reversal of methacholine-induced bronchoconstriction. The b2 agonists that are delivered by dry-powder inhaler (DPI) can be an efficacious option. Objective: To evaluate the effectiveness and speed of action of salbutamol delivered by DPI (Pulvinal; Butoventâ), in comparison to salbutamol delivered by MDI, in reversing methacholine-induced bronchoconstriction. Method: Sixty successive methacholine-induced bronchoconstriction patients who presented a decrease of at least 20% in forced expiratory volume (FEV1) were evaluated prospectively. Of these 60 patients, we randomized 30 (first group) to receive 200 mcg of salbutamol by MDI and 30 (second group) to receive 200 mcg of salbutamol by DPI (Pulvinal). Both drugs were administered with the objective of reversing bronchoconstriction during the final phase of a bronchoprovocation test. The FEV1 values obtained at 1 and 5 minutes after bronchodilator administration were evaluated. Results: The groups were comparable in gender distribution, age, weight, dose level provoking a 20% drop in FEV1 (first group: 1.3 mg; second group: 1.19 mg; p = 0.79) and post-methacholine FEV1 (first group: 2.03 l; second group: 1.99 l; p = 0.87), with no statistically significant differences between the two groups. In the first group (MDI), the mean increase in FEV1 was 16.2% (at 1 minute) and 22.2% (at 5 minutes), and in the second group (DPI) it was 17% (at 1 minute) and 23.6% (at 5 minutes). There was no statistically significant difference between the groups (p = 0.8). Conclusion: The b2-agonists delivered by DPI (Pulvinal) present the same bronchodilator efficacy and speed of action as do those delivered by the more traditional MDI method.

Keywords: Asthma. Bronchodilator agents/administration & dosage. Albuterol/administration & dosage. Methacholine chloride/administration & dosage. Respiratory therapy/methods. Administration, inhalation/methods. Prospective studies.

Summary: b-agonists are considered the agents of first choice for the treatment of asthmatic symptoms and are usually available for aerosol administration. Its propellants damage the ozone layer and are often not used properly by the patients. Turbuhaler seems a better alternative since it does not present these inconveniences. In Brazil, it has been recently introduced. Purpose: Compare salbutamol aerosol (SA) to terbutaline turbuhaler (TT) in relation to technical use, bronchodilation and adverse effects in outpatients with mild-obstruction asthma (PFR ³ 60 and < 80% predicted). Material and methods: Open, parallel randomized study performed in each arm of 20 patients (SA: 200 mg and TT: 500 mg). After 30 minutes, a second dose was given if PFR was not 15% or 30 L/min greater than the initial one; a second dose was also delivered if PFR was not greater than 80%. All patients were instructed on how to use both devices. Results: Clinical improvement and increase in PFR were similar in both groups (SA 69.5 vs. TT 58.1 L/min, p > 0.05). A second dose was given to 13 patients (SA 6 and TT 7) with similar results. Errors in the usage were observed in all 20 patients of group SA vs. 11 patients in group TT (p < 0.05). Adverse effects were more frequent with TT - 9 patients - due to its unpleasant taste. Fifteen patients of group TT and with previous experience with SA considered turbuhaler easier. Conclusions: 1) administration by the patient is easier with turbuhaler than with SA; 2) bronchodilation is not different with SA 200 mg and TT 500 mg; 3) unpleasant taste was noted only in group TT (50% of the patients).

Keywords: Asthma. Salbutamol aerosol. Terbutaline Turbuhaler.

Objective: To identify incorrect inhaler techniques employed by patients with respiratory diseases in southern Brazil and to profile the individuals who make such errors. Methods: This was a population-based, cross-sectional study involving subjects ≥ 10 years of age using metered dose inhalers (MDIs) or dry powder inhalers (DPIs) in 1,722 households in the city of Pelotas, Brazil. Results: We included 110 subjects, who collectively used 94 MDIs and 49 DPIs. The most common errors in the use of MDIs and DPIs were not exhaling prior to inhalation (66% and 47%, respectively), not performing a breath-hold after inhalation (29% and 25%), and not shaking the MDI prior to use (21%). Individuals ≥ 60 years of age more often made such errors. Among the demonstrations of the use of MDIs and DPIs, at least one error was made in 72% and 51%, respectively. Overall, there were errors made in all steps in 11% of the demonstrations, whereas there were no errors made in 13%.Among the individuals who made at least one error, the proportion of those with a low level of education was significantly greater than was that of those with a higher level of education, for MDIs (85% vs. 60%; p = 0.018) and for DPIs (81% vs. 35%; p = 0.010).Conclusions: In this sample, the most common errors in the use of inhalers were not exhaling prior to inhalation, not performing a breath-hold after inhalation, and not shaking the MDI prior to use. Special attention should be given to education regarding inhaler techniques for patients of lower socioeconomic status and with less formal education, as well as for those of advanced age, because those populations are at a greater risk of committing errors in their use of inhalers.

Keywords: Asthma; Pulmonary disease, chronic obstructive; Dry powder inhalers; Metered dose inhalers.

Objective: To evaluate the effectiveness and onset of action of formoterol delivered by dry-powder inhaler in reversing methacholine-induced bronchoconstriction. Methods: Patients presenting a drop in forced expiratory volume in one second > 20% after methacholine inhalation were included. A total of 84 patients were evaluated. All of the participating patients presented respiratory symptoms of unknown origin, which were being investigated. The patients were randomized to receive 200 µg of spray fenoterol (n = 41) or 12 µg of dry-powder inhaler formoterol (n = 43), both administered in order to achieve immediate reversal of methacholine-induced bronchoconstriction. We evaluated the decrease in forced expiratory volume in one second (in relation to the baseline value) after methacholine challenge and the dose of methacholine required to provoke a drop of 20% in forced expiratory volume in one second, as well as the increase in forced expiratory volume in one second (in relation to the baseline value) at five and ten minutes after bronchodilator use. Results: There were no significant differences related to gender, age, weight, height or dose of methacholine required to provoke a drop of 20% in forced expiratory volume in one second. Nor were there any significant differences in terms of baseline or post-methacholine forced expiratory volume in one second. In the fenoterol group, the mean postbronchodilator increase in forced expiratory volume in one second increase was 34% (at five minutes) and 50.1% (at ten minutes), compared with 46.5% (at five minutes) and 53.2% (at ten minutes) in the formoterol group. Conclusion: The bronchodilator effect of formoterol at five and ten minutes after methacholine-induced bronchoconstriction was similar to that of fenoterol. Despite being a long-acting bronchodilator, formoterol also has a rapid onset of action, which suggests that it could be employed as a relief medication in cases of bronchoconstriction occurring during asthma attacks.

Keywords: Asthma; Formoterol; Fenoterol; Inhalation therapy; Bronchodilation, Methacoline

Climate change is a huge and present threat to human health. This article aims to deepen the knowledge about the environmental impact of inhaler devices on their carbon footprint for patients and health professionals, providing information that allows a better choice of the type of device to be prescribed for the treatment of asthma and COPD. This narrative and nonsystematic review was carried out by searching databases (PubMed, Google Scholar, SciELO, and EMBASE) for articles published between 2017 and 2022, written in Portuguese or in English, using the search words "inhalation device" OR "environmental." The review showed that global warming cannot be addressed by focusing only on inhaler devices. However, the devices that we use to treat respiratory diseases such as asthma and COPD, which are diseases that are aggravated by climate change, are also causing that change. Therefore, health professionals, patient organizations, and industries should take a lead in health policies to offer affordable alternatives to inhalers containing hydrofluoroalkane.

Keywords: Asthma; Pulmonary disease, chronic obstructive; Environmental health; Nebulizers and vaporizers.

Objective: To assess possible alterations in the tidal volume and peak inspiratory pressure delivered by seven models of manually operated self-inflating resuscitation bags as a function of the oxygen supply rate used. Methods: The resuscitation bags tested were the following: Oxigel, models A and B; CE Reanimadores; ProtecSolutions; Missouri; Axmed; and Narcosul. For the measurements, a wall oxygen flow meter, a flow meter/respirometer, a resuscitation bag, a sensor (Tracer 5 unit), and a test lung were connected. In addition, the Tracer 5 unit was connected to a notebook computer. Oxygen supply rates of 1, 5, 10, and 15 L/min were used. Results: The tidal volume delivered by the Oxigel model A resuscitation bag when receiving oxygen at a rate of 15 L/min was approximately 99% greater than that delivered when receiving oxygen at a rate of 1 L/min. Similarly, peak inspiratory pressure was approximately 155% greater. Under the same conditions, the tidal volume delivered by the Narcosul resuscitation bag was 48% greater, and peak inspiratory pressure was 105% greater. The remaining resuscitation bags tested showed no significant alterations in the tidal volume or peak inspiratory pressure delivered. Conclusions: Under the resistance and compliance conditions used, the resuscitation bags in which the oxygen inflow is directed to the interior of the bag had the patient valve stuck at the inspiratory position when receiving oxygen at a rate ≥ 5 L/min, significantly increasing the tidal volume and peak inspiratory pressure delivered. This did not occur with the resuscitation bags in which the oxygen inflow is directed to the exterior of the bag.

Keywords: Oxygen/administration & dosage; Resuscitation; Equipment and supplies; Pulmonary ventilation; Intensive care.

Acceptability, preference, tolerance and clinical efficacy of dipropionate beclomethasone delivered by two inhalation devices in chronic asthma patients: Clenil pulvinal versus Miflasona Aerolizer Background: Approximately half of all asthmatic patients adhere to their prescribed treatment regimen, which makes noncompliance with treatment one of the main problems associated with the disease. It is possible that inhalation devices combining technological advances with comfort and simplicity of use could increase treatment compliance. Objective: To compare the acceptability of and preference for two inhalation devices (Pulvinal and Aerolizer), as well as to evaluate the efficacy of and tolerance for beclomethasone dipropionate when delivered by these two systems. Method: A multicenter, randomized, crossover parallel study was carried out involving 83 patients with stable asthma. Patients received 500-1000 g/day of beclomethasone dipropionate. After a 2-week run in, the patients were randomized to begin a 4-week crossover treatment period with equivalent doses of Clenil Pulvinal (CP) or Miflasona Aerolizer (MA). Results: Both groups showed improvement in dyspnea and FEV1, and acceptability was considered good or excellent in both groups. Of the patients studied, 50.6% preferred CP, and 39% preferred MA. In their future treatment regimes, 54.5% would choose the CP and 37.7% the MA. Conclusion: Clinical efficacy and acceptability were comparable between CP and MA.

Keywords: Asthma/therapy. Beclomethasone/ administration & dosage. Randomized controlled trials. Treatment Outcome.

Objective: To study the effects of short-term exposure to high oxygen concentrations (hyperoxia) on Wistar rat lungs. Methods: Animals were divided into three groups exposed to hyperoxia for 10', 30' and 90' (O10', O30', O90', respectively), together with a control group (exposed to room air). The animals were sacrificed 24 h after exposure. Bronchoalveolar lavage was performed, and the lungs were removed for histological and stereological analysis. Results: In the O10', O30', and O90' groups, respectively and in comparison with the controls, we observed an increase in the numbers of macrophages (2169.9 ± 118.0, 1560.5 ± 107.0, and 1467.6 ± 39.0 vs. 781.3 ± 78.3) and neutrophils (396.3 ± 35.4, 338.4 ± 17.3, and 388.7 ± 11.7 vs. 61.6 ± 4.2), concomitant with an increase in oxidative damage (143.0 ± 7.8%, 180.4 ± 5.6%, and 235.0 ± 13.7% vs. 100.6 ± 1.7%). The histological and stereological analyses revealed normal alveoli and alveolar septa in the controls (83.51 ± 1.20% and 15 ± 1.21%), in the O10' group (81.32 ± 0.51% and 16.64 ± 0.70%), and in the O30' group (78.75 ± 0.54% and 17.73 ± 0.26%). However, in the O90' group, inflammatory cell infiltration was observed in the alveoli and alveolar septa. Red blood cells extravasated from capillaries to the alveoli (59.06 ± 1.22%), with evidence of congestion, hemorrhage, and septal edema (35.15 ± 0.69%). Conclusion: Hyperoxia for 90' caused injury of the lung parenchyma, resulting in oxidative damage and inflammatory cell infiltration.

Keywords: Hyperoxia; Lung/injuries; Oxidative stress.

Introduction: The use of inhaled drugs through metered-dose inhaler has been advocated for years. Nonetheless, a small number of patients are routinely treated by this technique. Prescriptions of inhaled drugs by healthcare providers are not frequent, usually because they anticipate patients will not be able to perform the technique correctly. In addition, healthcare providers do not usually take their time to appropriately teach patients how to use metered-dose inhalers correctly. Objective: To evaluate the percentage of uninstructed patients that learn how to use a metered-dose inhaler correctly after being taught by a pneumologist. Patients and methods: One hundred and nineteen patients from a private clinic were prospectively studied in São Paulo, southeastern Brazil. Patients were exhaustively taught how to use the metered-dose inhaler at the first consultation and were told to return after 10 days, when they were asked to perform the technique exactly the way they were doing it at home. Their performance was classified as correct, slightly incorrect, intermediately incorrect, and totally incorrect. Results: Twenty-six patients were excluded for not coming to the second appointment. The final sample comprised 93 patients. Age ranged from 9 to 81 years (mean age 42.6 ± 21); 59.2% of the patients were male and 40.8% female. Considering all patients, only 16.25 of them used the metered-dose inhaler totally incorrectly and 19.3% performed the technique intermediately incorrectly. The most frequent mistakes were: metered-dose inhaler device was placed inside the mouth; inspiration before jet was activated; fast aspiration; inspiration through the nose. Thirty-three percent of patients who were under 15 and over 75 years performed the technique correctly. Conclusion: This study has demonstrated that the majority of the patients learned how to use the metered-dose inhaler correctly after being properly and extensively taught.

Keywords: Nebulizers and vaporizers. Inhalation administration. Learning.

Objective: To determine the oxygen outflow delivered by seven different models of manually operated self-inflating resuscitation bags (with and without an oxygen reservoir connected), which were tested using different oxygen supply rates without manipulating the bag, by simulating their use in patients breathing spontaneously. Methods: The oxygen outflow was measured using a wall oxygen flow meter and a flow meter/respirometer attached to the bag, together with another flow meter/respirometer attached to the patient connection port. The resuscitation bags that allow the connection of an oxygen reservoir were tested with and without this device. All resuscitation bags were tested using oxygen supply rates of 1, 5, 10, and 15 L/min. Statistical analyses were performed using analysis of variance and t-tests. Results: The resuscitation bags that allow the connection of an oxygen reservoir presented a greater oxygen outflow when this device was connected. All resuscitation bags delivered a greater oxygen outflow when receiving oxygen at a rate of 15 L/min. However, not all models delivered a sufficient oxygen outflow even when the two previous conditions were satisfied. Conclusions: Of the resuscitation bags studied, those that allow the connection of an oxygen reservoir must have this reservoir connected to the bag when used as a source of oxygen in nonintubated spontaneously breathing patients. All of the models studied should receive oxygen at a rate ≥ 15 L/min. It is not safe to use manually operated self-inflating resuscitation bags for this purpose without knowing their characteristics.

Keywords: Oxygen/administration & dosage; Resuscitation; Equipment and supplies; Respiration; Intensive care.

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: This study aimed to investigate acute and chronic effects of varenicline on lung tissue in an experimental study. Methods: A total of 34 rats were randomly allocated into study (varenicline) and control groups. The rats were divided into two groups (i) control group, (ii) varenicline group. Then, the rats in the each group were sub‑divided equally in turn as acute (C1; V1) and chronic (C2; V2) ; all rats of acute and chronic groups were sacrificed under the anesthesia on the 45th day for acute group [C1 (n=5) and V1 (n=12)] and the 90th day for chronic group [C2 (n=5) and V2 (n=12)], respectively. Thus, biochemical and histopathological analysis were carried out. Results: Thirty four rats completed the study, 24 were in varenicline group and 10 were in control group. In chronic exposure to varenicline, oxidant levels comprising of malondialdehyde (MDA), and myeloperoxidase (MPO) increased and superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) and glutathione peroxidase (GPx) levels, named as antioxidants, decreased significantly when compared to the control group. MDA and MPO levels were also significantly higher and SOD, CAT, GPx, GSH levels were also significantly lower in chronic varenicline group when compared to acute varenicline group. These findings were also supported by histopathological observations. Conclusion: This is the first study, which evaluated pulmonary effects of varenicline experimentally on an animal model. It was observed that chronic varenicline treatments cause inflammation and lung cell injury.

Keywords: Varenicline; Lung tissue; Oxidative stress; Pulmonary toxicity.

Objective: To determine the principal adverse effects of the tuberculosis treatment regimen recommended by the Brazilian Ministry of Health. Methods: A prospective descriptive study involving 79 tuberculosis patients treated at the Clinical Research Center of the Cassiano Antonio Moraes University Hospital, in the city of Vitória, Brazil, between 2003 and 2006. The treatment regimen consisted of isoniazid, rifampicin, pyrazinamide and ethambutol for four months, followed by rifampicin and isoniazid for two months. During the treatment period, the patients were clinically evaluated every week and had a monthly medical visit. Results: The overall incidence of adverse effects was 83.54%. Articular/bone/muscle involvement was the most common, followed by skin involvement (24.94% and 22.09%, respectively). Adverse effects were more common in the second month of treatment (41.59%). Modification of the treatment regimen was unnecessary. One patient required concomitant medication to counter the adverse effects. The cure rate was 100%. Conclusions: The overall incidence of adverse effects related to the new treatment regimen recommended by the Brazilian Ministry of Health was high. However, none of those effects demanded a change in the regimen, which was effective in the patients evaluated.

Keywords: Treatment outcome;Tuberculosis; Antitubercular agents; Adverse drug reaction reporting systems.

Objective: To compare the bronchodilatory effect of salbutamol delivered by metered-dose inhaler connected to spacers with and without previous antistatic treatment. Design: Prospective, randomized, open, crossover study. Setting: Outpatients from The Pulmonary Clinic of Hospital Júlia Kubitschek-FHEMIG, Belo Horizonte, Minas Gerais, Brazil. Patients and methods: Eleven patients, with stable mild to moderate asthma were randomized to four inhalation tests of 100 mg of salbutamol: (A) open mouth, (B) non antistatic small volume spacer (50 ml), (C) antistatic small volume spacer (50 ml) and (D) antistatic Fisonair® (750 ml). The antistatic treatment consisted in soaking the spacer in a solution of water and detergent for ten minutes and letting it to drip dry without rinsing. Main outcome measure: The peak expiratory flow (PEF) variation 15 minutes after each test in absolute, % of predicted and % of baseline values. Results: The median (Min-Max) PEF absolute variation was 25 (5-85), 40 (0-70), 70 (25-83) and 60 (15-90) l/min for tests A, B, C and D, respectively. The median PEF % baseline variation was 7.6, 11.0, 15.0, 13.3, and median PFE % predicted variation was 6.0, 8.7, 12.7 and 10.7 for tests A, B, C and D, respectively. The results of tests C and D were significantly superior to those of tests A and B (p < 0.01) based on the three methods evaluated. There was no significant difference between the results of tests C and D. Conclusion: The antistatic treatment of a small volume spacer device using a solution of water and detergent can improve the antiasthmatic effect of inhaled drugs delivered by metered-dose inhaler, as occurred with the salbutamol in this study. This fact can be more relevant concerning the treatment with inhaled steroids for asthma.

Keywords: Asthma. Respiratory therapy. Aerosols. Albuterol.

Objective: To study the effects that pneumoperitoneum achieved through carbon dioxide insufflation has on diaphragmatic excursion in pigs. Methods: A total of 14 male Landrace pigs, 30 to 45 days of age and weighing five to seven kilograms each, were used. The sample was randomly and equally divided into two groups: one (n = 7) in which pneumoperitoneum was maintained at 10 mmHg for 60 minutes; and another (n = 7) in which pneumoperitoneum was maintained at 15 mmHg (also for 60 minutes). After anesthetic induction, the animals were intubated. Flow volume was monitored, and the amplitude of diaphragmatic excursion was analyzed using noninvasive ultrasound imaging of the right hemidiaphragm. Results: In both groups, restricted diaphragmatic excursion was observed only during the procedure. There was no statistical difference between the two pressure levels studied. Conclusion: The amplitude of diaphragmatic excursion was restricted during abdominal insufflation, independent of the pressure level (within the 10-15 mmHg range), during the study period.

Keywords: Pneumoperitoneum/chemically induced; Carbon dioxide; Diaphragm; Video-assisted surgery; Swine

Objective: To evaluate the effects that early and late systemic administration of methylprednisolone have on lungs in a rat model of brain death. Methods: Twenty-four male Wistar rats were anesthetized and randomly divided into four groups (n = 6 per group): sham-operated (sham); brain death only (BD); brain death plus methylprednisolone (30 mg/kg i.v.) after 5 min (MP5); and brain death plus methylprednisolone (30 mg/kg i.v.) after 60 min (MP60). In the BD, MP5, and MP60 group rats, we induced brain death by inflating a balloon catheter in the extradural space. All of the animals were observed and ventilated for 120 min. We determined hemodynamic and arterial blood gas variables; wet/dry weight ratio; histological score; levels of thiobarbituric acid reactive substances (TBARS); superoxide dismutase (SOD) activity; and catalase activity. In BAL fluid, we determined differential white cell counts, total protein, and lactate dehydrogenase levels. Myeloperoxidase activity, lipid peroxidation, and TNF-α levels were assessed in lung tissue. Results: No significant differences were found among the groups in terms of hemodynamics, arterial blood gases, wet/dry weight ratio, BAL fluid analysis, or histological score-nor in terms of SOD, myeloperoxidase, and catalase activity. The levels of TBARS were significantly higher in the MP5 and MP60 groups than in the sham and BD groups (p < 0.001). The levels of TNF-α were significantly lower in the MP5 and MP60 groups than in the BD group (p < 0.001). Conclusions:áIn this model of brain death, the early and late administration of methylprednisolone had similar effects on inflammatory activity and lipid peroxidation in lung tissue.

Objective: To determine the effects of acute and chronic administration of methylprednisolone on oxidative stress, as quantified by measuring lipid peroxidation (LPO) and total reactive antioxidant potential (TRAP), in rat lungs. Methods: Forty Wistar rats were divided into four groups: acute treatment, comprising rats receiving a single injection of methylprednisolone (50 mg/kg i.p.); acute control, comprising rats i.p. injected with saline; chronic treatment, comprising rats receiving methylprednisolone in drinking water (6 mg/kg per day for 30 days); and chronic control, comprising rats receiving normal drinking water. Results: The levels of TRAP were significantly higher in the acute treatment group rats than in the acute control rats, suggesting an improvement in the pulmonary defenses of the former. The levels of lung LPO were significantly higher in the chronic treatment group rats than in the chronic control rats, indicating oxidative damage in the lung tissue of the former. Conclusions: Our results suggest that the acute use of corticosteroids is beneficial to lung tissue, whereas their chronic use is not. The chronic use of methylprednisolone appears to increase lung LPO levels.

Keywords: Lung; Methylprednisolone; Glucocorticoids; Lipid peroxidation; Antioxidant response elements.

Objective: 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.

Keywords: Saccharum; Smoke; Inflammation; Respiratory system.