Effects Of Airway Inflammation, Responsiveness And Sensory Nerves Of Normal Rats After Exposed To Low Concentration Of Sulfur Dioxide

With the developing of industrialization all over the world, people who are enjoying the richness and comfort which the industrial civilization brings to, they are also enduring the health hazards caused by environmental pollution. In the past several decades, the prevalence of asthma has been rising so fast that we can't explain it by the changing of gene bank.Then people think whether there were close associations between the increasing of asthma prevalence and air pollution.The results of epidemiological researchs were discordant in different areas and different study.It's reason might concerned with the multiplicity of asthma's etiopathogenisis .1990,American Clean Air Act Amendments (CAAA) ruled six kind of air pollutants: ozone(O₃),sulfur dioxide(SO₂),nitrogen dioxide (NO₂), particulate matter(PM),carbon monoxide(CO) and lead. SO₂ is a acor and blackdamp,it can decreases the physiological function of respiratory apparatus;and also fails the flexibility of alveoli pulmonum,cuts down lung function, produces tracheitis, bronchial asthma, emphysema,etc. epidemiological evidences indicated that when the concentration of SO₂ over 0.15mg/m³,PM over 2.0mg/m³,the hospitalization rate of disease of respiratory system increased.Patients of disease of respiratory system ,the higher concentration of SO₂ would make them cough,cough sputum and dyspnea more serious . But the pathomechanism that SO₂ injure airway is not very clear. Nielsen GD,a Danmark scholar,had provided a new hypothesis,he presumed the mechanism of air pollution inducing or sharpening asthma is that pollutant stimulate the sensory nerves in the airway and thus produce neurogenic inflammation. SP (Substance P) is one kind of neuropeptide which reside in airway amyelination sensory nerves.The liberation of SP would increase airway mucous secretion, and enhance airway smooth muscle contraction.Through this experiment,we explore the physiopathological mechanisms of airway injury and the effect on the airway responsiveness of rat by inhaled SO₂.And provide theoretical proof for the prevention and cure of respiratory system diseases and the management of envoroment.1 Effects of airway inflammation and airway responseness of normal rats after exposed to low concentration of sulfur dioxideAim:Raise the animal model and observe Effects of airway inflammation and airway responseness of normal rats after exposed to low concentration of sulfur dioxide.Methods: we imitated the concentration of SO₂ in air pollution,and let the rats inhal the contaminated air for three days,thus we raised the animal model.The control group raised in the room in which the air was filtered.we measured the rat's airway responsiveness by use methacholine provocating.Results:we found that the PC20IP of SO₂ group was decreased obviously(P<0.01).It indicated that rats wluld be induced bronchial hyperresponsiveness after exposed to low concentration of sulfur dioxide. We also made bronchoalveolar lavage and then count the total cellular score in the BALF.There were a significant rise of total cellular score in the SO₂ group's BALF. HE staining showed there were a great deal of inflammatory cells infiltration under the tunica mucosa bronchiorum.2 The mechanism of airway neurogenic inflammation of normal rats after exposed to low concentration of sulfur dioxideAim:To explore the mechanism of airway neurogenic inflammation of normal rats after exposed to low concentration of sulfur dioxide . Methods:we collected the rats's plasma and lung tissue . Then we measured the plasma SP content and made the immunohistochemistry staining on the lung tissue. Results:Compared with the control group , the plasma SP content in SO₂ group's increased significantly. And SP immunohistochemistry staining Indicated there were significant changes in numbers of SP-IR positive fibers of SO₂ group.Conclution:1. SO₂ is one of the major pollutant of air pollution. Through our experiments, after exposed to low concentration of sulfur dioxide, we found that rats wluld be induced bronchial hyper-responsiveness. We also made bronchoalveolar lavage and then count the total cellular score in the BALF.There were a significant rise of total cellular score in the SO₂ group's BALF. HE staining showed there were a great deal of inflammatory cells infiltration under the tunica mucosa bronchiorum.It indicated that exposure to low concentration of SO₂ would injure healthy rat's airway, and induce airway hyperresponsiveness.2. After exposed to low concentration of sulfur dioxid, the plasma SP content in SO₂ group's increased significantly. And SP immunohistochemistry staining Indicated there were significant changes in numbers of SP-IR positive fibers of SO₂ group.The experiment confirmed that SO₂ can produce airway neurogenic inflammation of normal rats, and it is one of its critical physiopathological mechanisms of COPD and asthma.