| Sažetak | Ozone is known air pollutant, contained in photochemical smog, produced in atmosphere due to high concentration of oxides and influence of electrical discharge and UV light. It can cause or increase severity of pulmonary disease like airway hyperreactivity (AHR), chronic obstructive pulmonary disease (COPD) and some forms of asthma. Safety dose of ozone has been estimated to approximately 0,01ppm and dose used in murine systems is 5-10 times higher because of rodent’s higher resistance to ozone. High dose of ozone can cause lung inflammation and injury which are manifested as neutrophilia, macrophage infiltration, damage on bronchial epithelium and elevated levels of IL-1β, IL-6, KC, IL-8, MMP-9, caspase-9 and several other immune proteins and immune related proteins. Several experiments were performed using experimental mice of different genotype, C57BL/6J, IL-17Ra knock-out, IL-22 knock-out, IL-17Ra/IL-22 knock out. All mice were between 8 and 11 weeks old and were exposed to 1,5ppm of ozone during 3h. Exposures were performed once per day, one, two or three days in a row. Mice were sacrificed 24h after last exposure. Control mice were exposed to normal air. During the necropsy bronchial-alveolar lavage was performed, obtaining BAL fluid used for differential cell counting, protein dosage and ELISA assay in order to evaluate level of lung inflammation. Lung injury was assessed by histological observation of lung samples obtained during the necropsy and staining with haematoxylin/eosin stain (H&E) or performing immunohistochemistry analysis with Anti-Uteroglobin antibody as a specific marker of Clara cells. Stress caused by ozone exposure was observed by measuring body weight loss of ozone-exposed mice 24h after each exposure. Aim of the study was to determine level of lung inflammation and injury caused by single or multiple acute ozone exposures and to determine potential role of IL-22 and IL-17A. From obtained results, it can be concluded that acute ozone exposure causes high level of stress observed as change in behaviour of mice during the exposure and decrease in body weight after each exposure. Ozone causes high macrophage infiltration constant with numbers of exposures and neutrophil infiltration that increases with number of exposures. It is also possible to say that IL-22 and IL-17Ra definitely play role in ozone-induced lung inflammation/injury, probably acting as proinflammatory factors stimulating macrophage, neutrophil and lymphocyte infiltration. Inactivation of each of these cytokines results in decrease in neutrophil, macrophage and lymphocyte number and also lowers down the protein leakage but, interestingly, increases histopathology signs in bronchiolar epithelium. Clear function of these cytokine has not been determined yet so more experiments should be performed in future. Role of these cytokines should be tested also on subacute ozone exposure model and on higher ozone level acute models. Also, it is necessary to determine which type of cells are responsible for production of these cytokines in ozone-induced lung inflammation/injury model. Each step in discovering the path (or pathways) of immune response to ozone, we are step closer to finding solution of problems that ozone causes to millions of people with pulmonary disease on daily base. |
