FA/OVA Sham-OVx group; p<0

FA/OVA Sham-OVx group; p<0.05vs. additional week, the rats were challenged with ovalbumin (1%) by an aerosol route. The leukocyte numbers, interleukin-10 (IL-10) release, myeloperoxidase activity, vascular permeability,ex vivotracheal reactivity to methacholine and mast cell degranulation were decided 24 h later. == RESULTS: == Our results showed that previous exposure to formaldehyde in allergic rats decreased lung cell recruitment, tracheal reactivity, myeloperoxidase activity, vascular permeability and mast cell degranulation while increasing IL-10 levels. Ovariectomy only caused an additional reduction in tracheal reactivity without changing the PKR Inhibitor other parameters studied. Progesterone treatment reversed the effects of formaldehyde exposure onex vivotracheal reactivity, cell influx into the lungs and mast cell degranulation. == CONCLUSION: == In conclusion, our study revealed that formaldehyde and ovariectomy downregulated allergic lung inflammation by IL-10 release and mast cell degranulation. Progesterone treatment increased eosinophil recruitment and mast cell degranulation, which in turn may be responsible for tracheal hyperreactivity and allergic lung inflammation. Keywords:Formaldehyde Exposure, Progesterone, Lung inflammation, Tracheal reactivity, Mast cells, Interleukin-10 == INTRODUCTION == Formaldehyde (FA) is usually a pollutant that is widely employed in many industries and in anatomy, pathology and histology laboratories (1). FA is also emitted in tobacco smoke, burning fuel, urea-FA foam insulation, cosmetics, solvents and domestic disinfectants (2). FA exposure causes irritation of the eyes and mucous membranes and induces airway inflammation. Many people are exposed to FA, and its role as a risk factor in the development of asthma is still controversial. In previous studies, we reported that both male and female rats developed lung inflammation when exposed to FA inhalation (3,4). Interestingly, ovary removal caused a decrease in the inflammatory response induced by FA exposure (4). Clinical and experimental data have both exhibited a putative role of female sex hormones (FSHs) in lung inflammation (49). Progesterone has been suggested to mediate eosinophilia, airway hyperreactivity and interleukin (IL)-5 production in murine models of allergic lung inflammation (10). Moreover, progesterone skews the differentiation of nave T helper lymphocytes toward the Th2lineage in vitro (11). Studies have shown that estradiol and progesterone both exert pro- and anti-inflammatory effects on lung inflammation, depending on the nature of the inflammatory agent (allergic or non-allergic) (4,7,12,13). In this regard, our group has exhibited that ovariectomy (OVx) reduces lung inflammation when PKR Inhibitor an inflammatory agent is related to ovalbumin (OVA), the allergic stimulus. Moreover, this effect is usually reversed by estradiol but not by progesterone (5,7). Conversely, pre-treatment with estradiol or progesterone re-established the inflammatory response when the stimulus was related to FA exposure (a non-allergic stimulus) (4). In other studies, we also exhibited that pre-exposure to FA in OVA-sensitized and OVA-challenged male rats blunted the allergic lung response (14). Therefore, both FA exposure and ovary removal suppressed the development of an allergic lung response induced by OVA. Considering these earlier results, we investigated the role of ovary removal when considering the effect of FA on lung inflammation induced by OVA. Moreover, because we observed in earlier studies that progesterone had pro-inflammatory effects in rats submitted to FA inhalation and that its effects were worse than those observed PKR Inhibitor in rats treated with estradiol, we decided to investigate the involvement of progesterone in leukocyte migration into the lung,ex vivotracheal reactivity Mouse monoclonal to His Tag. Monoclonal antibodies specific to six histidine Tags can greatly improve the effectiveness of several different kinds of immunoassays, helping researchers identify, detect, and purify polyhistidine fusion proteins in bacteria, insect cells, and mammalian cells. His Tag mouse mAb recognizes His Tag placed at Nterminal, Cterminal, and internal regions of fusion proteins. to methacholine (MCh), IL-10 release in the lung tissue and mast cell degranulation. == MATERIALS AND PKR Inhibitor METHODS == == Animals == Female Wistar rats (160180 g) were obtained from the Institute of Biomedical Sciences, University of So Paulo. The rats were housed in groups (5 rats per cage) in a light- and temperature-controlled room (12/12-h light-dark cycle, 212C) with free access to food and water. The experiments were approved by the Institutional Animal Care Committee. == Ovariectomy (OVx) == Female rats were anesthetized with intraperitoneal ketamine-xylazine (Konig, So Paulo, Brazil) (100 and 20 mg/kg, respectively), and their ovaries were removed. Following the medical procedures, the rats received a single dose of Pentantibiotic (Fort Dodge, IA) (570 mg/kg, intramuscular). Vaginal smears and uterine weight measurements.