ABSTRACT
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.
Subject(s)
Airway Remodeling/radiation effects , Asthma/radiotherapy , Bronchoconstriction/radiation effects , Cytokines/metabolism , Hypersensitivity/radiotherapy , Low-Level Light Therapy , Airway Remodeling/drug effects , Airway Remodeling/physiology , Amides/pharmacology , Animals , Asthma/drug therapy , Asthma/physiopathology , Bronchi/drug effects , Bronchi/physiopathology , Bronchi/radiation effects , Bronchial Hyperreactivity/drug therapy , Bronchial Hyperreactivity/physiopathology , Bronchial Hyperreactivity/radiotherapy , Bronchoconstriction/drug effects , Bronchoconstriction/physiology , Enzyme Inhibitors/pharmacology , Hypersensitivity/drug therapy , Hypersensitivity/physiopathology , Lung/drug effects , Lung/physiopathology , Lung/radiation effects , Male , Mice , Mice, Inbred BALB C , Muscle, Smooth/drug effects , Muscle, Smooth/physiopathology , Muscle, Smooth/radiation effects , Ovalbumin/adverse effects , Pneumonia/drug therapy , Pneumonia/physiopathology , Pneumonia/radiotherapy , Pyridines/pharmacology , STAT6 Transcription Factor/metabolism , rho GTP-Binding Proteins/antagonists & inhibitors , rho GTP-Binding Proteins/metabolism , rhoA GTP-Binding ProteinABSTRACT
Low-level laser therapy (LLLT) has been found to produce anti-inflammatory effects in a variety of disorders. Bronchial smooth muscle (BSM) hyperreactivity is associated with increased Ca+2 sensitivity and increased RhoA mRNA expression. In the current study, we investigated if LLLT could reduce BSM contraction force and RhoA mRNA expression in tumor necrosis factor-alpha (TNF-alpha)-induced BSM hyperreactivity. In the study, 112 male Wistar rats were divided randomly into 16 groups, and BSM was harvested and suspended in TNF-alpha baths for 6 and 24 h, respectively. Irradiation with LLLT was performed with a wavelength of 660 nm for 42 s with a dose of 1.3 J/cm2. This LLLT dose was administered once in the 6-h group and twice in the 24-h group. LLLT significantly decreased contraction force in BSM at 6 h (TNF-alpha + LLLT: 11.65+/-1.10 g/100 mg of tissue) (F=3115) and at 24 h (TNF-alpha+ LLLT: 14.15+/-1.1 g/100 mg of tissue) (F=3245, p<0.05) after TNF-alpha, respectively, when compared to vehicle-bathed groups (control). LLLT also significantly decreased the expression of RhoA mRNA in BSM segments at 6 h (1.22+/-0.20) (F=2820, p<0.05) and 24 h (2.13+/-0.20) (F=3324, p<0.05) when compared to BSM segments incubated with TNF-alpha without LLLT irradiation. We conclude that LLLT administered with this protocol, reduces RhoA mRNA expression and BSM contraction force in TNF-alpha-induced BSM hyperreactivity.
Subject(s)
Bronchi/drug effects , Bronchi/radiation effects , Low-Level Light Therapy , Muscle, Smooth/drug effects , Muscle, Smooth/radiation effects , RNA, Messenger/genetics , RNA, Messenger/metabolism , Tumor Necrosis Factor-alpha/pharmacology , rhoA GTP-Binding Protein/genetics , Amides/pharmacology , Animals , Bronchi/metabolism , Bronchial Hyperreactivity/chemically induced , Bronchial Hyperreactivity/genetics , Bronchial Hyperreactivity/radiotherapy , Calcium Signaling/radiation effects , Gene Expression/drug effects , Gene Expression/radiation effects , In Vitro Techniques , Male , Muscle, Smooth/metabolism , Pyridines/pharmacology , Rats , Rats, WistarABSTRACT
The objective of this study was to investigate whether low level laser therapy (LLLT) could reduce bronchial hyper-responsiveness (BHR) induced by tumour necrosis factor-alpha (TNF-alpha) modulating the metabolism of inositol phosphate (IP) in bronchial smooth muscle cells (BSMCs). The study was on 28 Wistar rats, randomly divided into four groups. Irradiation (1.3 J/cm(2)) was administered 5 min and 4 h after bronchial smooth muscle (BSM) had been suspended in TNF-alpha baths, and the contractile response-induced calcium ion (Ca(2+)) sensitization was measured. The BSMCs were isolated, and the IP accumulation was measured before and after TNF-alpha immersion in the groups that had been irradiated or not irradiated. BSM segments significantly increased contraction 24 h after TNF-alpha immersion when exposed to carbachol (CCh) as Ca(2+), but it was significantly reduced by 64% and 30%, respectively, after laser treatment. The increase in IP accumulation induced by CCh after TNF-alpha immersion was reduced in the BSMCs by LLLT. The dose of 2.6 J/cm(2) reduced BHR and IP accumulation in the rats' inflammatory BSMCs.
Subject(s)
Bronchial Hyperreactivity/radiotherapy , Low-Level Light Therapy , Animals , Base Sequence , Bronchial Hyperreactivity/chemically induced , Bronchial Hyperreactivity/physiopathology , Calcium/metabolism , Carbachol/pharmacology , DNA Primers/genetics , Gene Expression/radiation effects , In Vitro Techniques , Inositol 1,4,5-Trisphosphate Receptors/genetics , Inositol 1,4,5-Trisphosphate Receptors/metabolism , Inositol Phosphates/metabolism , Macrocyclic Compounds/pharmacology , Male , Muscle Contraction/drug effects , Muscle Contraction/radiation effects , Myocytes, Smooth Muscle/drug effects , Myocytes, Smooth Muscle/physiology , Myocytes, Smooth Muscle/radiation effects , Oxazoles/pharmacology , RNA, Messenger/genetics , RNA, Messenger/metabolism , Rats , Rats, Wistar , Tumor Necrosis Factor-alpha/pharmacologyABSTRACT
BACKGROUND: Over recent decades, there has been a significant global increase in the prevalence of asthma, an inflammatory disease of the respiratory system. While ultraviolet radiation (UV) has been used successfully in the treatment of inflammatory conditions such as psoriasis, studies of UV-induced regulation of allergic respiratory responses have been rare, and have not analysed in vivo measurements of airway hyperresponsiveness (AHR) or the antigen specificity of the UV-induced effects. OBJECTIVE: To investigate the regulatory properties of erythemal ultraviolet B (UVB) irradiation of the skin and the induction of allergen-induced airway immunity in a murine asthma model, and to examine the mechanisms involved. METHODS: BALB/c mice were exposed to a single erythemal dose of UV 3 days before intraperitonial sensitization (day 0) and boost (day 14) with the antigen, ovalbumin (OVA). Airway-associated, asthma-like responses to aerosolized OVA at day 21 were analysed including (a) AHR measured in vivo, (b) OVA-specific proliferative responses and cytokine production by cells from the lung-draining lymph nodes (LDLN), and (c) inflammatory cells and cytokines in the bronchoalveolar lavage fluid. To determine UVB-induced mechanisms of regulation, LDLN cells from UVB irradiated, OVA-sensitized mice were adoptively transferred into naïve BALB/c mice that were subsequently sensitized and challenged with OVA, or a non-specific antigen. RESULTS: UVB irradiation of skin significantly suppressed AHR to methacholine and OVA-specific responses in the LDLN and in the lung compartment. Reduced OVA-specific responses by LDLN cells from both UVB irradiated mice and mice that received 5 x 10(6) LDLN cells from UVB irradiated, but not from non-irradiated, OVA-sensitized mice suggested that UVB-induced regulatory cells are responsible for many of the asthma-reducing effects of dorsal UVB exposure. CONCLUSION: UVB irradiation of skin suppresses AHR and cellular responses of the airways to respiratory allergens. Further, this study implicates UVB or its downstream mediators as a potential approach to reducing the severity of asthma.
Subject(s)
Asthma/immunology , Bronchial Hyperreactivity/immunology , Ultraviolet Therapy , Animals , Asthma/chemically induced , Asthma/radiotherapy , Bronchial Hyperreactivity/chemically induced , Bronchial Hyperreactivity/radiotherapy , Bronchoalveolar Lavage Fluid/chemistry , Bronchoalveolar Lavage Fluid/cytology , Cytokines/analysis , Disease Models, Animal , Female , Immunity, Cellular , Immunization/methods , Immunoglobulin E/blood , Lymph Nodes/immunology , Male , Methacholine Chloride/adverse effects , Mice , Mice, Inbred BALB C , Ovalbumin/adverse effects , Phenotype , Rats , Rats, Sprague-Dawley , Ultraviolet RaysABSTRACT
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.
