Low radiation dose to treat pneumonia and other inflammations.

Infection, the invasion of pathogenic microorganisms and viruses, causes reactive inflammation mediated by endogenous signals, with influx of leucocytes with distinct properties and capable of mounting a cellular or antibody response. Different forms of inflammation may also occur in response to tumours, in allergy and autoimmune disorders. Pneumonia, respiratory tract infection and septic shock for instance can arise as serious complications of the Covid-19 virus. While radiotherapy has been most widely used to control malignant tumours, it has also been used for treatment of non-malignant diseases, including acute and chronic inflammation in situations where anti-inflammatory drugs may be ineffective or contraindicated. The present review examines the history and prospects for low-dose anti-inflammatory radiation treatments, the present interest largely being motivated by the increased incidence of pulmonary disease associated Covid-19 infections. Evidence in support of the suggested efficacy are covered, together with an appraisal of one of the number of potential convenient sources that could complement external beam arrangements.

Photobiomodulation therapy as a high potential treatment modality for COVID-19.

COVID-19 is now a worldwide concern, causing an unprecedented pandemic. The infected cases show different symptoms based on the severity of the disease. In asymptomatic and non-severe symptomatic cases, the host immune system can successfully eliminate the virus and its effects. In severe cases, however, immune system impairment causes cytokine release syndrome which eventually leads to acute respiratory distress syndrome (ARDS). In recent years, photobiomodulation (PBM) has shown promising results in reducing acute pulmonary inflammation. Considering the high potential impact of PBM on immune responses, we hypothesized that using PBM could be an effective treatment modality for ARDS management in COVID-19 patients.

Probable positive effects of the photobiomodulation as an adjunctive treatment in COVID-19: A systematic review.

BACKGROUND: COVID-19, as a newly-emerged viral infection has now spread all over the world after originating in Wuhan, China. Pneumonia is the hallmark of the disease, with dyspnea in half of the patients and acute respiratory distress syndrome (ARDS) in up to one -third of the cases. Pulmonary edema, neutrophilic infiltration, and inflammatory cytokine release are the pathologic signs of this disease. The anti-inflammatory effect of the photobiomodulation (PBM) has been confirmed in many previous studies. Therefore, this review study was conducted to evaluate the direct effect of PBM on the acute lung inflammation or ARDS and also accelerating the regeneration of the damaged tissues. The indirect effects of PBM on modulation of the immune system, increasing the blood flow and oxygenation in other tissues were also considered. METHODOLOGY: The databases of PubMed, Cochrane library, and Google Scholar were searched to find the relevant studies. Keywords included the PBM and related terms, lung inflammation, and COVID-19 -related signs. Studies were categorized with respect to the target tissue, laser parameters, and their results. RESULTS: Seventeen related papers were included in this review. All of them were in animal models. They showed that the PBM could significantly decrease the pulmonary edema, neutrophil influx, and generation of pro-inflammatory cytokines (tumor necrosis factor-α (TNF-α), interleukin 1 beta (IL-1ß), interleukin 6 (IL-6), intracellular adhesion molecule (ICAM), reactive oxygen species (ROS), isoform of nitric oxide synthase (iNOS), and macrophage inflammatory protein 2 (MIP-2)). CONCLUSION: Our findings revealed that the PBM could be helpful in reducing the lung inflammation and promoting the regeneration of the damaged tissue. PBM can increase the oxygenation indirectly in order to rehabilitate the affected organs. Thus, the infra-red lasers or light-emitting diodes (LEDs) are recommended in this regard.

Low dose lung radiation therapy for pneumonia: an examination of historical dose distributions.

The novel coronavirus, SARS-CoV-2, that causes the COVID-19 disease currently has healthcare systems around the world dealing with unprecedented numbers of critically ill patients. One of the primary concerns associated with this illness is acute respiratory distress syndrome (ARDS) and the pneumonia that accompanies it. Historical literature dating back to the 1940s and earlier contains many reports of successful treatment of pneumonias with ionizing radiation. Although these were not randomized controlled trials, they do suggest a potential avenue for further investigation. Technical details in these reports however were limited. In this work we review the literature and identify details including nominal kilovoltage ranges, filtration, and focus-skin distances (FSDs). Using a freely available and benchmarked code, we generated spectra and used these as sources for Monte Carlo simulations using the EGSnrc software package. The approximate sources were projected through a radiologically anthropomorphic phantom to provide detailed dose distributions within a targeted lung volume (approximate right middle lobe). After accounting for the reported exposure levels, mean lung doses fell in a relatively narrow range: 30-80 cGy. Variation in patient dimensions and other details are expected to result in an uncertainty on the order of ± 20%. This result is consistent with the dose range expected to induce anti-inflammatory effects.

[The influence of low-intensity laser radiation on the functional activity of neutrophils in the patients presenting with community-acquired pneumonia].

AIM: The objective of the present study was to elucidate the influence of low-intensity laser radiation on the results of the nitroblue tetrazolium (NBT) test in the patients presenting with community-acquired pneumonia. PATIENTS AND METHODS: A total of 100 patients with community-acquired pneumonia were available for the examination of whom 70 were treated with intravenous low-intensity laser irradiation of blood (ILIB) by means of the ILIB-405 technique during 7 days. The functional activity of neutrophils was estimated from their ability to reduce nitroblue tetrazolium in both spontaneous and stimulated NBT-tests. RESULTS: The analysis of the data obtained in the study has demonstrated the significant improvement of the results of the NBT tests in the group of patients receiving the ILIB treatments regardless of whether its content was originally elevated or reduced. CONCLUSION: The inclusion of intravenous low-intensity laser irradiation of blood in the combined treatment of the patients with community-acquired pneumonia appreciably promotes normalization of the bactericidal activity of neutrophils.

Low Level Laser Therapy Reduces the Development of Lung Inflammation Induced by Formaldehyde Exposure.

Lung diseases constitute an important public health problem and its growing level of concern has led to efforts for the development of new therapies, particularly for the control of lung inflammation. Low Level Laser Therapy (LLLT) has been highlighted as a non-invasive therapy with few side effects, but its mechanisms need to be better understood and explored. Considering that pollution causes several harmful effects on human health, including lung inflammation, in this study, we have used formaldehyde (FA), an environmental and occupational pollutant, for the induction of neutrophilic lung inflammation. Our objective was to investigate the local and systemic effects of LLLT after FA exposure. Male Wistar rats were exposed to FA (1%) or vehicle (distillated water) during 3 consecutive days and treated or not with LLLT (1 and 5 hours after each FA exposure). Non-manipulated rats were used as control. 24 h after the last FA exposure, we analyzed the local and systemic effects of LLLT. The treatment with LLLT reduced the development of neutrophilic lung inflammation induced by FA, as observed by the reduced number of leukocytes, mast cells degranulated, and a decreased myeloperoxidase activity in the lung. Moreover, LLLT also reduced the microvascular lung permeability in the parenchyma and the intrapulmonary bronchi. Alterations on the profile of inflammatory cytokines were evidenced by the reduced levels of IL-6 and TNF-α and the elevated levels of IL-10 in the lung. Together, our results showed that LLLT abolishes FA-induced neutrophilic lung inflammation by a reduction of the inflammatory cytokines and mast cell degranulation. This study may provide important information about the mechanisms of LLLT in lung inflammation induced by a pollutant.

Low-level laser therapy inhibits bronchoconstriction, Th2 inflammation and airway remodeling in allergic asthma.

Low-level laser therapy (LLLT) controls bronchial hyperresponsiveness (BHR) associated with increased RhoA expression as well as pro-inflammatory mediators associated with NF-kB in acute lung inflammation. Herein, we explore if LLLT can reduce both BHR and Th2 cytokines in allergic asthma. Mice were studied for bronchial reactivity and lung inflammation after antigen challenge. BHR was measured through dose-response curves to acetylcholine. Some animals were pretreated with a RhoA inhibitor before the antigen. LLLT (660 nm, 30 mW and 5.4 J) was applied on the skin over the right upper bronchus and two irradiation protocols were used. Reduction of BHR post LLLT coincided with lower RhoA expression in bronchial muscle as well as reduction in eosinophils and eotaxin. LLLT also diminished ICAM expression and Th2 cytokines as well as signal transducer and activator of transduction 6 (STAT6) levels in lungs from challenged mice. Our results demonstrated that LLLT reduced BHR via RhoA and lessened allergic lung inflammation via STAT6.

Suppressive effect of low-level laser therapy on tracheal hyperresponsiveness and lung inflammation in rat subjected to intestinal ischemia and reperfusion.

Intestinal ischemia and reperfusion (i-I/R) is an insult associated with acute respiratory distress syndrome (ARDS). It is not known if pro- and anti-inflammatory mediators in ARDS induced by i-I/R can be controlled by low-level laser therapy (LLLT). This study was designed to evaluate the effect of LLLT on tracheal cholinergic reactivity dysfunction and the release of inflammatory mediators from the lung after i-I/R. Anesthetized rats were subjected to superior mesenteric artery occlusion (45 min) and killed after clamp release and preestablished periods of intestinal reperfusion (30 min, 2 or 4 h). The LLLT (660 nm, 7.5 J/cm(2)) was carried out by irradiating the rats on the skin over the right upper bronchus for 15 and 30 min after initiating reperfusion and then euthanizing them 30 min, 2, or 4 h later. Lung edema was measured by the Evans blue extravasation technique, and pulmonary neutrophils were determined by myeloperoxidase (MPO) activity. Pulmonary tumor necrosis factor-α (TNF-α), interleukin-10 (IL-10), intercellular adhesion molecule-1 (ICAM-1), and isoform of NO synthase (iNOS) mRNA expression were analyzed by real-time PCR. TNF-α, IL-10, and iNOS proteins in the lung were measured by the enzyme-linked immunoassay technique. LLLT (660 nm, 7.5 J/cm(2)) restored the tracheal hyperresponsiveness and hyporesponsiveness in all the periods after intestinal reperfusion. Although LLLT reduced edema and MPO activity, it did not do so in all the postreperfusion periods. It was also observed with the ICAM-1 expression. In addition to reducing both TNF-α and iNOS, LLLT increased IL-10 in the lungs of animals subjected to i-I/R. The results indicate that LLLT can control the lung's inflammatory response and the airway reactivity dysfunction by simultaneously reducing both TNF-α and iNOS.

Dual Effect of low-level laser therapy (LLLT) on the acute lung inflammation induced by intestinal ischemia and reperfusion: Action on anti- and pro-inflammatory cytokines.

BACKGROUND AND OBJECTIVE: It is unknown if pro- and anti-inflammatory mediators in acute lung inflammation induced by intestinal ischemia and reperfusion (i-I/R) can be modulated by low-level laser therapy (LLLT). STUDY DESIGN/MATERIAL AND METHODS: A controlled ex vivo study was developed in which rats were irradiated (660 nm, 30 mW, 0.08 cm² of spot size) on the skin over the right upper bronchus 1 hour post-mesenteric artery occlusion and euthanized 4 hours later. For pretreatment with anti-tumor necrosis factor (TNF) or IL-10 antibodies, the rats received either one of the agents 15 minutes before the beginning of reperfusion. METHODS: Lung edema was measured by the Evans blue extravasation and pulmonary neutrophils influx was determined by myeloperoxidase (MPO) activity. Both TNF and IL-10 expression and protein in lung were evaluated by RT-PCR and ELISA, respectively. RESULTS: LLLT reduced the edema (80.1 ± 41.8 µg g⁻¹ dry weight), neutrophils influx (0.83 ± 0.02 × 106 cells ml⁻¹), MPO activity (2.91 ± 0.60), and TNF (153.0 ± 21.0 pg mg⁻¹ tissue) in lung when compared with respective control groups. Surprisingly, the LLLT increased the IL-10 (0.65 ± 0.13) in lung from animals subjected to i-I/R. Moreover, LLLT (0.32 ± 0.07 pg ml⁻¹) reduced the TNF-α level in RPAECs when compared with i-I/R group. The presence of anti-TNF or IL-10 antibodies did not alter the LLLT effect on IL-10 (465.1 ± 21.0 pg mg⁻¹ tissue) or TNF (223.5 ± 21.0 pg mg⁻¹ tissue) in lung from animals submitted to i-I/R. CONCLUSION: The results indicate that the LLLT attenuates the i-I/R-induced acute lung inflammation which favor the IL-10 production and reduce TNF generation.

Terapia com laser 670nm no tratamento da DPOC experimental em ratos / 670nm laser therapy in treatment of COPD in experimental rats

Introdução: DPOC é uma enfermidade respiratória com manifestações sistêmicas que se caracteriza pela presença de obstrução crônica do fluxo aéreo, associada a uma resposta inflamatória. Objetivo: Verificar o efeito da laserterapia de laser 670nm, no tratamento da inflamação pulmonar induzida em ratos. Metodologia: 30 ratos foram divididos em três grupos, dos quais dois foram expostos à fumaça de cigarro durante 45 dias e um deles tratados com laser 670nm. Para análise dos resultados foram realizados LBA e ELISA. Resultados: Os resultados foram submetidos à análise de variância (ANOVA), seguida do teste Newman- Keuls para amostras não pareadas. A análise do LBA demonstrou um aumento altamente significativo no número de neutrófilos no grupo DPOC. O grupo tratado, quando comparado ao grupo DPOC, evidenciou uma diminuição significativa no número de neutrófilos. Para o resultado do ELISA, houve queda altamente significativa de TNF-?, quando tratado com laser 670nm, e significativa de MIP-2 e IL-1?. Conclusão: Verifica-se que a ação do laser de 670nm pode atenuar o processo inflamatório induzido.

Introduction: COPD is a respiratory illness with systemic manifestations, characterized by the presence of chronic airflow obstruction associated with an inflammatory response. Objective: To investigate the effect of laser 670nm laser in the treatment of pulmonary inflammation induced in mice. Methods: 30 rats were divided into three groups, two of which were exposed to cigarette smoke for 45 days and one treated with 670 nm laser. For data analysis and ELISA were performed BAL. Results: Results were subjected to analysis of variance (ANOVA) followed by Newman-Keuls test for unpaired samples. BAL analysis showed a highly significant increase in neutrophils in the COPD group. The treated group compared with the COPD group showed a significant decrease in neutrophils. For the result of the ELISA results were highly significant decrease of TNF-? when treated with 670 nm laser, and the significant MIP-2 and IL-1?. Conclusion: It appears that the action of the 670nm laser can attenuate the inflammatory process induced.

Efeito da laserterapia de baixa potência na inflamação pulmonar em rattus novergicus / Effect of low level laser therapy on lung inflammation in rattus norvegicus

Introdução. A doença pulmonar obstrutiva crônica é uma enfermidade respiratória caracterizada pela presença de obstrução crônica do fluxo aéreo e manifestação inflamatória. Objetivo. Verificar o efeito da laserterapia de baixa potência no tratamento da inflamação pulmonar. Metodologia. Utilizou-se 30 ratos, divididos em três grupos de dez animais: grupo controle (recebeu apenas ar ambiente); grupo DPOC e grupo DPOC+laser (expostos à fumaça de cigarro durante 45 dias, sendo o grupo DPOC+laser tratado durante 12 dias com laser 904nm). Para análise dos resultados foi realizada histopatologia. Resultados. O grupo controle apresentou espaços aéreos normais com distorção arquitetural periférica do pulmão, o grupo DPOC demonstrou um enfisema acentuado, áreas de atelectasias e destruição das paredes alveolares. O grupo tratado houve uma regressão de enfisema acentuado para discreto. Conclusão. Na análise realizada, a inflamação pulmonar induzida pelo cigarro pode ser comprovada e a laserterapia de baixa potência mostrou-se eficaz na atenuação da inflamação.

Introduction. The chronic obstructive pulmonary disease is a respiratory disease characterized by chronic airflow obstruction and inflammatory manifestation. Objective. To investigate the effect of low level laser therapy in the treatment of pulmonary inflammation. Methodology. We used 30 rats divided into three groups of ten animals: control group (received only room air), group COPD and COPD + laser (exposed to cigarette smoke for 45 days with group COPD + laser treated for 12 days with 904nm laser). For data analysis was performed histopathology. Results. The control group had normal air spaces with architectural distortion of the peripheral lung, COPD group showed a marked emphysema, areas of atelectasis and destruction of alveolar walls in the treated group there was a regression from mild to severe emphysema. Conclusion. Through the analysis performed pulmonary inflammation induced by cigarette can be proved, and the low level laser therapy was effective in reducing inflammation.

[The rationale for the use of microwave resonance therapy in combined treatment of patients with community-acquired pneumonia].

Inclusion of microwave resonance therapy using waves of various frequency and alternating wavelength ranges in the combined treatment of patients with community-acquired pneumonia promoted normalization of their disturbed prooxidant-antioxidant status, correction of physico-chemical properties and functional activity of membranes.

Low intensity laser therapy (LILT) in vivo acts on the neutrophils recruitment and chemokines/cytokines levels in a model of acute pulmonary inflammation induced by aerosol of lipopolysaccharide from Escherichia coli in rat.

It has been suggested that low intensity laser therapy (LILT) acts on pulmonary inflammation. Thus, we investigate in this work if LILT (650nm, 2.5mW, 31.2mW/cm(2), 1.3J/cm(2), laser spot size of 0.08cm(2) and irradiation time of 42s) can attenuate edema, neutrophil recruitment and inflammatory mediators in acute lung inflammation. Thirty-five male Wistar rats (n=7 per group) were distributed in the following experimental groups: control, laser, LPS, LPS+laser and dexamethasone+LPS. Airway inflammation was measured 4h post-LPS challenge. Pulmonary microvascular leakage was used for measuring pulmonary edema. Bronchoalveolar lavage fluid (BALF) cellularity and myeloperoxidase (MPO) were used for measuring neutrophil recruitment and activation. RT-PCR was performed in lung tissue to assess mRNA expression of tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), interleukin (IL-10), cytokine-induced neutrophil chemoattractant-1 (CINC-1), macrophage inflammatory protein-2 (MIP-2) and intercellular adhesion molecule-1 (ICAM-1). Protein levels in both BALF and lung were determined by ELISA. LILT inhibited pulmonary edema and endothelial cytoskeleton damage, as well as neutrophil influx and activation. Similarly, the LILT reduced the TNF-α and IL-1ß, in lung and BALF. LILT prevented lung ICAM-1 up-regulation. The rise of CINC-1 and MIP-2 protein levels in both lung and BALF, and the lung mRNA expressions for IL-10, were unaffected. Data suggest that the LILT effect is due to the inhibition of ICAM-1 via the inhibition of TNF-α and IL-1ß.

A generalized linear-quadratic model for radiosurgery, stereotactic body radiation therapy, and high-dose rate brachytherapy.

Conventional radiation therapy for cancer usually consists of multiple treatments (called fractions) with low doses of radiation. These dose schemes are planned with the guidance of the linear-quadratic (LQ) model, which has been the most prevalent model for designing dose schemes in radiation therapy. The high-dose fractions used in newer advanced radiosurgery, stereotactic radiation therapy, and high-dose rate brachytherapy techniques, however, cannot be accurately calculated with the traditional LQ model. To address this problem, we developed a generalized LQ (gLQ) model that encompasses the entire range of possible dose delivery patterns and derived formulas for special radiotherapy schemes. We show that the gLQ model can naturally derive the traditional LQ model for low-dose and low-dose rate irradiation and the target model for high-dose irradiation as two special cases of gLQ. LQ and gLQ models were compared with published data obtained in vitro from Chinese hamster ovary cells across a wide dose range [0 to approximately 11.5 gray (Gy)] and from animals with dose fractions up to 13.5 Gy. The gLQ model provided consistent interpretation across the full dose range, whereas the LQ model generated parameters that depended on dose range, fitted only data with doses of 3.25 Gy or less, and failed to predict high-dose responses. Therefore, the gLQ model is useful for analyzing experimental radiation response data across wide dose ranges and translating common low-dose clinical experience into high-dose radiotherapy schemes for advanced radiation treatments.

Low level laser therapy (LLLT) decreases pulmonary microvascular leakage, neutrophil influx and IL-1beta levels in airway and lung from rat subjected to LPS-induced inflammation.

BACKGROUND AND OBJECTIVE: Low level laser therapy (LLLT) is a known anti-inflammatory therapy. Herein we studied the effect of LLLT on lung permeability and the IL-1beta level in LPS-induced pulmonary inflammation. STUDY DESIGN/METHODOLOGY: Rats were divided into 12 groups (n = 7 for each group). Lung permeability was measured by quantifying extravasated albumin concentration in lung homogenate, inflammatory cells influx was determined by myeloperoxidase activity, IL-1beta in BAL was determined by ELISA and IL-1beta mRNA expression in trachea was evaluated by RT-PCR. The rats were irradiated on the skin over the upper bronchus at the site of tracheotomy after LPS. RESULTS: LLLT attenuated lung permeability. In addition, there was reduced neutrophil influx, myeloperoxidase activity and both IL-1beta in BAL and IL-1beta mRNA expression in trachea obtained from animals subjected to LPS-induced inflammation. CONCLUSION: LLLT reduced the lung permeability by a mechanism in which the IL-1beta seems to have an important role.

Endobronchial brachytherapy for symptom palliation in non-small cell lung cancer--analysis of symptom response, endoscopic improvement and quality of life.

AIMS: Endobronchial brachytherapy (EBBT) is a useful modality for the palliation of endobronchial symptoms in advanced non-small cell lung cancer (NSCLC). We report our experience with a special emphasis on duration of symptom palliation and the impact on quality of life (QOL). MATERIALS AND METHODS: The records of 95 previously untreated patients with locally advanced NSCLC were treated with palliative radiation using EBBT with or without palliative external radiation (XRT) were analysed. Eighty patients received EBBT and palliative XRT. EBBT was delivered in two sessions of EBBT 8Gy each or a single session of 10Gy. Fifteen patients received EBBT alone to 15Gy in a single session. Symptomatic response rates, duration of symptom palliation, obstruction scores and complications were assessed and compared. Quality of life outcomes, measured using the EORTC QLQ C30 and LC13 questionnaires, were analysed. RESULTS: The overall symptomatic response rates were 93% for dyspnea, 81% for cough, 97% for haemoptysis and 91% for obstructive pneumonia. The median time to symptom relapse was 4-8 months for all symptoms, and the median time to symptom progression was 6-11 months. Quality of life showed significant improvement in symptom scores, functional scales and overall QOL. Complication rates were low. Only one patient died of fatal haemoptysis. CONCLUSION: EBBT is thus a safe and effective palliative tool in advanced non-small cell lung cancer, with a relatively long duration of symptom palliation and a considerable improvement in the quality of life. There is significant reduction of endobronchial obstruction.

Tomografia computadorizada de alta resolução nas complicações pulmonares pós-transplante de medula óssea: ensaio iconográfico / High-resolution computed tomography findings in pulmonary complications after bone marrow transplantation: iconographic essay

O transplante de medula óssea (TMO) tem sido utilizado como tratamento de escolha para diversas doenças hematológicas. Entretanto, as complicações pulmonares, que podem ocorrer em até 60 por cento dos pacientes, são o principal motivo de falha no tratamento. As complicações pulmonares pós-TMO podem ser divididas em três fases, de acordo com a imunidade do paciente. Na primeira fase, até 30 dias após o procedimento, predominam as complicações não infecciosas e as pneumonias fúngicas. Na fase precoce, que vai até o 100º dia pós-TMO, as infecções virais, principalmente por citomegalovírus, são mais comuns. Finalmente, na fase tardia pós-TMO, complicações não infecciosas como bronquiolite obliterante com pneumonia em organização e doença do enxerto contra o hospedeiro são mais comumente observadas. Os autores apresentam um ensaio iconográfico, enfatizando os aspectos de tomografia de alta resolução em pacientes com complicações pulmonares pós-TMO.

Bone marrow transplantation has been the treatment of choice for many hematologic diseases. However, pulmonary complications, which may occur in up to 60% of the patients, are the main cause of treatment failure and may be divided in three phases according to the patient's immunity. In the first phase, up to 30 days after the procedure, there is a predominance of non-infectious complications and fungal pneumonia. Viral infections, mainly by cytomegalovirus, are common in the second phase (up to 100 days after bone marrow transplantation). Finally, in the late phase after bone marrow transplantation, non-infectious complications as bronchiolitis obliterans organizing pneumonia and graft-versus-host disease are most commonly seen. The authors present a pictorial essay of the high-resolution computed tomography findings in patients with pulmonary complications after bone marrow transplantation.

Effect of LLLT Ga-Al-As (685 nm) on LPS-induced inflammation of the airway and lung in the rat.

The purpose of this study was to investigate the effect of low level laser therapy (LLLT) on male Wistar rat trachea hyperreactivity (RTHR), bronchoalveolar lavage (BAL) and lung neutrophils influx after Gram-negative bacterial lipopolyssacharide (LPS) intravenous injection. The RTHR, BAL and lung neutrophils influx were measured over different intervals of time (90 min, 6 h, 24 h and 48 h). The energy density (ED) that produced an anti-inflammatory effect was 2.5 J/cm(2), reducing the maximal contractile response and the sensibility of trachea rings to methacholine after LPS. The same ED produced an anti-inflammatory effect on BAL and lung neutrophils influx. The Celecoxib COX-2 inhibitor reduced RTHR and the number of cells in BAL and lung neutrophils influx of rats treated with LPS. Celecoxib and LLLT reduced the PGE(2) and TXA(2) levels in the BAL of LPS-treated rats. Our results demonstrate that LLLT produced anti-inflammatory effects on RTHR, BAL and lung neutrophils influx in association with inhibition of COX-2-derived metabolites.