Clarissa Bichara Magalhães

Low dose of fine particulate matter (PM2.5) can induce acute oxidative stress, inflammation and pulmonary impairment in healthy mice

Air pollution is associated with morbidity and mortality induced by respiratory diseases. However, the mechanisms therein involved are not yet fully clarified. Thus, we tested the hypothesis that a single acute exposure to low doses of fine particulate matter (PM2.5) may induce functional and histological lung changes and unchain inflammatory and oxidative stress processes. PM2.5 was collected from the urban area of São Paulo city during 24 h and underwent analysis for elements and polycyclic aromatic hydrocarbon contents. Forty-six male BALB/c mice received intranasal instillation of 30 μL of saline (CTRL) or PM2.5 at 5 or 15 μg in 30 μL of saline (P5 and P15, respectively). Twenty-four hours later, lung mechanics were determined. Lungs were then prepared for histological and biochemical analysis. P15 group showed significantly increased lung impedance and alveolar collapse, as well as lung tissue inflammation, oxidative stress and damage. P5 presented values between CTRL and P15: higher mechanical impedance and inflammation than CTRL, but lower inflammation and oxidative stress than P15. In conclusion, acute exposure to low doses of fine PM induced lung inflammation, oxidative stress and worsened lung impedance and histology in a dose-dependent pattern in mice.

Comparative respiratory toxicity of particles produced by traffic and sugar cane burning

The impact of particle emissions by biomass burning is increasing throughout the world. We explored the toxicity of particulate matter produced by sugar cane burning and compared these effects with equivalent mass of traffic-derived particles. For this purpose, BALB/c mice received a single intranasal instillation of either distilled water (C) or total suspended particles (15 microg) from an urban area (SP group) or biomass burning-derived particles (Bio group). Lung mechanical parameters (total, resistive and viscoelastic pressures, static elastance, and elastic component of viscoelasticity) and histology were analyzed 24h after instillation. Trace elements and polycyclic aromatic hydrocarbons (PAHs) metabolites of the two sources of particles were determined. All mechanical parameters increased similarly in both pollution groups compared with control, except airway resistive pressure, which increased only in Bio. Both exposed groups showed significantly higher fraction area of alveolar collapse, and influx of polymorphonuclear cells in lung parenchyma than C. The composition analysis of total suspended particles showed higher concentrations of PAHs and lower concentration of metals in traffic than in biomass burning-derived particles. In conclusion, we demonstrated that a single low dose of ambient particles, produced by traffic and sugar cane burning, induced significant alterations in pulmonary mechanics and lung histology in mice. Parenchymal changes were similar after exposure to both particle sources, whereas airway mechanics was more affected by biomass-derived particles. Our results indicate that biomass particles were at least as toxic as those produced by traffic.

In vivo anti-inflammatory action of eugenol on lipopolysaccharide-induced lung injury

Eugenol, a methoxyphenol component of clove oil, suppresses cyclooxygenase-2 expression, while eugenol dimers prevent nuclear factor-kappaB (NF-kappaB) activation and inflammatory cytokine expression in lipopolysaccharide-stimulated macrophages. Our aim was to examine the in vivo anti-inflammatory effects of eugenol. BALB/c mice were divided into four groups. Mice received saline [0.05 ml intratracheally (it), control (Ctrl) and eugenol (Eug) groups] or Escherichia coli LPS (10 microg it, LPS and LPSEug groups). After 6 h, mice received saline (0.2 ml ip, Ctrl and LPS groups) or eugenol (160 mg/kg ip, Eug and LPSEug groups). Twenty-four hours after LPS injection, pulmonary resistive (DeltaP1) and viscoelastic (DeltaP2) pressures, static elastance (E(st)), and viscoelastic component of elastance (DeltaE) were measured. Lungs were prepared for histology. In parallel mice, bronchoalveolar lavage fluid was collected 24 h after LPS injection. TNF-alpha was determined by ELISA. Lung tissue expression of NF-kappaB was determined by EMSA. DeltaP1, DeltaP2, E(st), and DeltaE were significantly higher in the LPS group than in the other groups. LPS mice also showed significantly more alveolar collapse, collagen fibers, and neutrophil influx and higher TNF-alpha levels and NF-kappaB expression than the other groups. Eugenol treatment reduced LPS-induced lung inflammation, improving lung function. Our results suggest that eugenol exhibits in vivo anti-inflammatory action in LPS-induced lung injury.

Redox markers and inflammation are differentially affected by atorvastatin, pravastatin or simvastatin administered before endotoxin-induced acute lung injury.

Statins are standard therapy for the treatment of lipid disorders, and the field of redox biology accepts that statins have antioxidant properties. Our aim in this report was to consider the pleiotropic effects of atorvastatin, pravastatin and simvastatin administered prior to endotoxin-induced acute lung injury. Male mice were divided into 5 groups and intraperitoneally injected with LPS (10 mg/kg), LPS plus atorvastatin (10 mg/kg/day; A + LPS group), LPS plus pravastatin (5 mg/kg/day; P + LPS group) or LPS plus simvastatin (20 mg/kg/day; S + LPS group). The control group received saline. All mice were sacrificed one day later. There were fewer leukocytes in the P + LPS and S + LPS groups than in the LPS group. MCP-1 cytokine levels were lower in the P + LPS group, while IL-6 levels were lower in the P + LPS and S + LPS groups. TNF-α was lower in all statin-treated groups. Levels of redox markers (superoxide dismutase and catalase) were lower in the A + LPS group (p < 0.01). The extent of lipid peroxidation (malondialdehyde and hydroperoxides) was reduced in all statin-treated groups (p < 0.05). Myeloperoxidase was lower in the P + LPS group (p < 0.01). Elastance levels were significantly greater in the LPS group compared to the statin groups. Our results suggest that atorvastatin and pravastatin but not simvastatin exhibit anti-inflammatory and antioxidant activity in endotoxin-induced acute lung injury.

Eugenol attenuates pulmonary damage induced by diesel exhaust particles

Environmentally relevant doses of inhaled diesel particles elicit pulmonary inflammation and impair lung mechanics. Eugenol, a methoxyphenol component of clove oil, presents in vitro and in vivo anti-inflammatory and antioxidant properties. Our aim was to examine a possible protective role of eugenol against lung injuries induced by diesel particles. Male BALB/c mice were divided into four groups. Mice received saline (10 μl in; CTRL group) or 15 μg of diesel particles DEP (15 μg in; DIE and DEUG groups). After 1 h, mice received saline (10 μl; CTRL and DIE groups) or eugenol (164 mg/kg; EUG and DEUG group) by gavage. Twenty-four hours after gavage, pulmonary resistive (ΔP1), viscoelastic (ΔP2) and total (ΔPtot) pressures, static elastance (Est), and viscoelastic component of elastance (ΔE) were measured. We also determined the fraction areas of normal and collapsed alveoli, amounts of polymorpho- (PMN) and mononuclear cells in lung parenchyma, apoptosis, and oxidative stress. Est, ΔP2, ΔPtot, and ΔE were significantly higher in the DIE than in the other groups. DIE also showed significantly more PMN, airspace collapse, and apoptosis than the other groups. However, no beneficial effect on lipid peroxidation was observed in DEUG group. In conclusion, eugenol avoided changes in lung mechanics, pulmonary inflammation, and alveolar collapse elicited by diesel particles. It attenuated the activation signal of caspase-3 by DEP, but apoptosis evaluated by TUNEL was avoided. Finally, it could not avoid oxidative stress as indicated by malondialdehyde.

Endotoxin-induced acute lung injury is dependent upon oxidative response

The aim of the present study was to investigate the involvement of oxidative stress in acute lung injury (ALI) induced by lipopolysaccharide (LPS) and its effects upon cell structure, function and inflammation. In total, 108 male C57BL/6 mice were divided into seven groups: CTR Group (50 µL of saline) administered intratracheally (i.t.), LPS 6 h (10 µg of LPS − i.t.), LPS 12 h (10 µg of LPS − i.t.), LPS 24 h (10 µg of LPS − i.t.), LPS 48 h (10 µg of LPS − i.t.), LPS 24 h (10 µg − i.t.) + NAC 40 mg/kg (gavage) and 24 h LPS (10 µg − i.t.) + NAC 100 mg/kg (gavage). The antioxidant treatment protected the lungs from stress in the first 12 h, but significant oxidative stress induction was observed at the 24-hour time point, and, after 48 h, there was no protection exerted by the antioxidant treatment. NAC (N-acetylcysteine) reversed the elastance parameters, and ΔP1 and ΔP2 compared with 24 h LPS alone. NAC reduced the number of inflammatory cells in histology analysis when compared with the 24 h LPS alone-treated group. NAC also inhibited the transcription of NFκB, IL-6, TNF-α and COX2 usually induced by LPS. Our results suggest that oxidative stress plays an important role in structural, functional and inflammatory responses in the ALI model.

Residual oil fly ash worsens pulmonary hyperreactivity in chronic allergic mice

BALB/c mice received saline (SAL groups) or ovalbumin (OVA groups) intraperitoneally (days 1, 3, 5, 7, 9, 11 and 13). After 27 days, a burst of intratracheal OVA or SAL (days 40, 43 and 46) was performed. Animals were then divided into four groups (N=8, each) and intranasally instilled with saline (SAL-SAL and OVA-SAL) or residual oil fly ash (SAL-ROFA and OVA-ROFA). 24h later, total, initial and difference resistances (Rtot, Rinit, Rdiff) and static elastance (Est) were measured. Lung responsiveness to methacholine was assessed as slope and sensitivity of Est, Rtot, Rinit, and Rdiff. Lung morphometry (collapsed and normal areas and bronchoconstriction index) and cellularity (polymorphonuclear, mononuclear and mast cells) were determined. OVA or ROFA similarly impaired lung mechanics and increased the amount of polymorphonuclear cells and collapsed areas. OVA-ROFA showed even higher hyperresponsiveness, bronchoconstriction and mast cell infiltration. Thus, we concluded that ROFA exposure may add an extra burden to hyperresponsive lungs.

Oxidative imbalance in mice intoxicated by microcystin-LR can be minimized

&NA; Microcystins‐LR (MC‐LR) is a cyanotoxin produced by cyanobacteria. We evaluated the antioxidant potential of LASSBio‐596 (LB‐596, inhibitor of phosphodiesterases 4 and 5), per os, and biochemical markers involved in lung and liver injury induced by exposure to sublethal dose of MC‐LR. Fifty male Swiss mice received an intraperitoneal injection of 60 &mgr;L of saline (CTRL group, n = 20) or a sublethal dose of MC‐LR (40 &mgr;g/kg, TOX group, n = 20). After 6 h the animals received either saline (TOX and CTRL groups) or LB‐596 (50 mg/kg, TOX + LASS group, n = 10) by gavage. At 6 h after exposure, respiratory mechanics was evaluated in 10 CTRL and 10 TOX mice: there was a significant increase of all lung mechanics parameters (static elastance, viscoelastic component of elastance and lung resistive and viscoelastic/inhomogeneous pressures) in TOX compared to CTRL. 8 h after saline or MC‐LR administration, i.e., 2 h after treatment with LB‐596, blood serum levels of alanine aminotransferase and aspartate aminotransferase, activity of superoxide dismutase, catalase, and content of malondialdehyde and carbonyl in lung and liver, NADPH oxidase 2 and 4 mRNA expressions, dual oxidase enzyme activity and H2O2 generation were analyzed in lung homogenates. All parameters were significantly higher in TOX than in the other groups. There was no significant difference between CTRL and TOX + LASS. MC‐LR deteriorated lung and liver functions and induced redox imbalance in them, which was prevented by oral administration of LB‐596. HighlightsThe effects of LASSBio 596 (LB‐596) per os were evaluated in an acute model of intoxication by microcystin‐LR (MC‐LR).MC‐LR impaired lung and liver functions, as well as produced oxidative stress and damage.Treatment with LB‐596 improved lung and liver oxidative stress and damage and recovered liver function.

The anti-inflammatory and anti-oxidative actions of eugenol improve lipopolysaccharide-induced lung injury

Acute lung injury (ALI) remains a major cause of mortality. In lipopolysaccharide (LPS)-stimulated macrophages, eugenol reduces cyclooxygenase-2 expression, NF-κB activation, and inflammatory mediators. We examined the anti-inflammatory and anti-oxidative action of eugenol in an in vivo model of LPS-induced lung injury. Lung mechanics and histology were analyzed in mice 24 h after LPS exposure, with and without eugenol treatment at different doses. Additional animals, submited to the same protocol, were treated with eugenol at 150 mg/kg to determine its effect on inflammatory cytokines (ELISA) and oxidative markers. LPS-induced lung functional and histological changes were significantly improved by eugenol, in a dose-dependent way. Furthermore, eugenol (150 mg/kg) was able to inhibit the release of inflammatory cytokines (TNF-α, IL-1β and IL-6), NADPH oxidase activity, as well as antioxidant enzymes activity (superoxide dismutase, catalase and glutathione peroxidase). Finally, eugenol reduced LPS-induced protein oxidation. In conclusion, eugenol improved in vivo LPS-induced ALI through both anti-inflammatory and anti-oxidative effects, avoiding damage to lung structure.

Exercise Capacity and Respiratory Profile in Patients after Orthopedic Liver Transplantation: a Follow-up Study

INTRODUCTION We sought to describe: 1) The influence of orthotopic liver transplantation (OLT) on exercise capacity, pulmonary function and respiratory muscle strength after surgery, 2) The relationship between exercise capacity and symptoms of anxiety and depression. MATERIAL AND METHODS This is a prospective follow up study conducted with patients submitted to OLT. All patients were assessed before and 1 month after surgery through measurements: six minute walk test (6MWT), 6 min step test (6MST) and HADS (Hospital Anxiety and Depression Scale). FEV1% (forced expiratory volume), maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) were measured in the pre-operative and on 1st, 3rd, 5th day and 1 month after surgery. RESULTS In 77 patients, 6MWD improved 20.2 m (95%CI 8.1-32.3) and 6MST improved 7.8 steps after surgery (95%CI 3.9-11.6). Change in 6 MWD and 6 MST did not correlated with change HADS. The FEV1% at each time point were 88.8 ± 21.3 before surgery, 32.9 ± 9.9 on 1st day, 39.6 ± 11.5 on 3rd day, 46 ± 12.1 on 5th day and 86.6 ± 21.1 one month after surgery. MIP and MEP values at each time point were -67.4 ± 23.2 and 79.7 ± 26 before surgery, -30.8 ± 12.3 and 36.4 ± 15.4 on 1st day, -38.6 ± 14.1 and 43.8 ± 17 on 3rd day, -45.8 ± 15.9 and 49.7 ± 18.7 on 5th day and -67.1 ± 29.4 and 80.9 ± 23.9 one month after surgery. CONCLUSION Exercise capacity was modestly increased after OLT without any correlation with symptoms of anxiety and depression. Pulmonary function and respiratory muscle strength decreased immediately after liver transplantation, and progressively recovered, returning to baseline values after 1 month.INTRODUCTION We sought to describe: 1) The influence of orthotopic liver transplantation (OLT) on exercise capacity, pulmonary function and respiratory muscle strength after surgery, 2) The relationship between exercise capacity and symptoms of anxiety and depression. MATERIAL AND METHODS This is a prospective follow up study conducted with patients submitted to OLT. All patients were assessed before and 1 month after surgery through measurements: six minute walk test (6MWT), 6 min step test (6MST) and HADS (Hospital Anxiety and Depression Scale). FEV1% (forced expiratory volume), maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) were measured in the pre-operative and on 1st, 3rd, 5th day and 1 month after surgery. RESULTS In 77 patients , 6MWD improved 20.2 m (95%CI 8.1-32.3) and 6MST improved 7.8 steps after surgery (95%CI 3.9-11.6). Change in 6 MWD and 6 MST did not correlated with change HADS. The FEV1% at each time point were 88.8 ± 21.3 before surgery, 32.9 ± 9.9 on 1st day, 39.6 ± 11.5 on 3rd day, 46 ± 12.1 on 5th day and 86.6 ± 21.1 one month after surgery. MIP and MEP values at each time point were -67.4 ± 23.2 and 79.7 ± 26 before surgery, -30.8 ± 12.3 and 36.4 ± 15.4 on 1st day, -38.6 ± 14.1 and 43.8 ± 17 on 3rd day, -45.8 ± 15.9 and 49.7 ± 18.7 on 5th day and -67.1 ± 29.4 and 80.9 ± 23.9 one month after surgery. CONCLUSION Exercise capacity was modestly increased after OLT without any correlation with symptoms of anxiety and depression. Pulmonary function and respiratory muscle strength decreased immediately after liver transplantation, and progressively recovered, returning to baseline values after 1 month.