BACKGROUND AND OBJECTIVE: Evidence has shown that aminophylline has bronchoprotective, anti-inflammatory, and immunomodulatory effects. Our purpose was to evaluate the effect of different doses of aminophylline on the late-phase reaction, bronchial hyperresponsiveness (BHR) and T cell-related cytokine mRNA expression in brown Norway rats induced by ovalbumin (OA) sensitization. METHODS: Forty rats were equally divided into four groups. Groups I, II, and III animals were sensitized and subsequently provoked with OA. Aminophylline 25 mg/kg was given intraperitoneally to the group I animals and 5 mg/kg to group II animals. Group III animals received intraperitoneal normal saline. Group IV breathed aerosolized saline as a control. After OA provocation, the animals were anesthetized. Pulmonary function tests were performed at baseline and after varying doses of acetylcholine. Thereafter, bronchoalveolar lavage was performed and the lungs were examined histologically. Total RNA was extracted from lung tissue and reverse transcriptase-polymerase chain reaction was performed using primers for interleukin (IL)-2, IL-4, IL-5, IL-6, IL-10, interferon-gamma, inducible nitric oxide synthase, and beta-actin. RESULTS: Group III had worse pulmonary function tests, more severe BHR, and more severe lung inflammation, higher IL-4 and IL-10 cytokine levels in bronchoalveolar lavage fluid, and higher IL-4, IL-5, IL-6, IL-10, tumor necrosis factor-alpha and inducible nitric oxide synthase mRNA expression than the other three groups. Expression of IL-2 and interferon-gamma was significantly reduced in group III. CONCLUSIONS: Both low and high dose aminophylline are effective in preventing late-phase bronchoconstriction, BHR, and an inflammatory response. Aminopylline decreases T helper cell 2-related cytokine mRNA expression but increases T helper cell 1-related cytokines mRNA expression.
Unité de Recherche, Centre de Pneumologie, Dept de Radiologie, Institut Universitaire de Cardiologie et de Pneumologie, Hôpital Laval, 2725 Chemin Ste Foy, Ste Foy, Québec, Canada, G1V 4G5. firstname.lastname@example.org
What is the significance of serum precipitins and lymphocytic alveolitis in a healthy subject exposed to antigens responsible for hypersensitivity pneumonitis (HP)? This study was done to evaluate the 20-yr outcome of asymptomatic dairy farmers with or without precipitins or lymphocytic alveolitis in their bronchoalveolar lavage (BAL). Twenty-seven of the initial 43 farmers were restudied. Of the missing 16, 11 refused the follow-up, three had died and two could not be located. The restudied farmers had a clinical evaluation, lung function tests and a high resolution computed tomography (HRCT). Only one subject, an asthmatic, had dyspnoea, none described present or past symptoms suggestive of HP. Of those who were no longer on the farm, none had quit because of respiratory problems. Lung function changes were as expected with aging. The only difference was that farmers with positive precipitins had a statistically significant greater decrease in their forced expiratory volume in one second than the sero-negative farmers. Four HRCTs showed signs of minimal parenchymal abnormalities; these were not more prevalent for subjects with or without precipitins or BAL lymphocytosis. Serum precipitins and asymptomatic lymphocytic alveolitis in an asymptomatic, exposed dairy farmer have no clinically meaningful long-term consequences.