title: Tracheal responsiveness to methacholine and ovalbumin; and lung inflammation in guinea pigs exposed to inhaled lead after sensitization.
abstract: The association between lead exposure and asthma is controversial. The effect of inhaled lead acetate on lung inflammation, tracheal responsiveness and immune components in guinea pigs after sensitization was examined in this study. Five groups of guinea pigs were randomly allocated to control (group C), sensitized (group S), and three test groups exposed to inhaled lead concentrations 0.1, 0.2 and 0.4M Pb after sensitization (n=6 for each group). The measured variables included tracheal responsiveness to methacholine and ovalbumin (OA); total and differential white blood cells (WBC) counts of lung lavage; serum cytokine levels (IFN-γ and IL-4); and lead concentration in lung tissue. Tracheal responsiveness to methacholine and OA; total and differential WBC counts; IL-4 and IFN-γ were significantly increased in sensitized animals compared to control group (p<0.05 to p<0.001). However, the ratio of IFN-γ/IL-4 were significantly decreased in group S (p<0.05). In addition, all measured parameters in animals exposed to highest lead concentration and most of them in animals exposed to medium lead concentration were significantly higher than group S, except for the IFN-γ and IFN-γ/IL-4 ratio, which were significantly decreased (p<0.05 to p<0.001). The lead concentration in lung tissues of all test animals was significantly higher than that of group C (p<0.001 for all groups). These results showed that lead acetate exposure can cause further increase in tracheal responsiveness to methacholine and OA, total and differential WBC count and IL-4, IFN-γ and IFN-γ/IL-4 ratio. Therefore, environmental exposure to lead may aggravate the severity of asthma.
authors.affiliation: Department of Physiology, School of Medicine and Pharmaceutical Research Centre, Mashhad University of Medical Sciences, Mashhad, Islamic Republic of Iran. mhboskabady@hotmail.com
authors.forename: Mohammad Hossein
authors.initials: MH
authors.lastname: Boskabady
authors.forename: Gholam Reza
authors.initials: GR
authors.lastname: Karimi
authors.forename: Saeed
authors.initials: S
authors.lastname: Samarghandian
authors.forename: Tahere
authors.initials: T
authors.lastname: Farkhondeh
mesh_terms: D000280:Administration, Inhalation; D000818:Animals; D016085:Bronchoconstrictor Agents / Q000494:pharmacology; D006168:Guinea Pigs; D007107:Immune System / Q000187:drug effects; D007371:Interferon-gamma / Q000097:blood; D015847:Interleukin-4 / Q000097:blood; D007854:Lead / Q000032:analysis; D007958:Leukocyte Count; D007962:Leukocytes / Q000187:drug effects; D008168:Lung / Q000737:chemistry / Q000187:drug effects*; D016210:Methacholine Chloride / Q000494:pharmacology*; D009942:Organometallic Compounds / Q000633:toxicity*; D010047:Ovalbumin / Q000494:pharmacology*; D011014:Pneumonia / Q000139:chemically induced*; D011897:Random Allocation; D014132:Trachea / Q000187:drug effects*
chemical_list: D016085:Bronchoconstrictor Agents; D009942:Organometallic Compounds; D016210:Methacholine Chloride; D015847:Interleukin-4; D007854:Lead; D007371:Interferon-gamma; D010047:Ovalbumin; C008261:lead acetate