title: Localization of extracellular superoxide dismutase in rat lung: neutrophils and macrophages as carriers of the enzyme.
abstract: Immunohistochemistry (IHC) and in situ hybridization (ISH) was used to localize extracellular superoxide dismutase (EC-SOD) and its mRNA in rat lung before and after a lipopolysaccharide (LPS)- and hyperoxia-induced inflammation. In control rats, EC-SOD mRNA was synthesized in macrophages and in cells of the arterial vessel walls and the alveolar septa. The EC-SOD protein was mainly localized in plasma and on the apical side of the epithelial cells located near bronchus-associated lymphoid tissue (BALT). ISH did not reveal major changes in the distribution of EC-SOD mRNA upon induction of inflammation. In contrast, IHC demonstrated a progressive staining of the epithelium of the larger bronchi for the protein. Neutrophils and macrophages invading the lung showed an intensive staining for the EC-SOD protein concomitantly with a decrease of the enzyme in the plasma. Twenty-four hours after LPS stimulation only a spotty positivity remained on neutrophils in and between the alveolar spaces. In the bronchoalveolar lavage fluid (BALF), only macrophages showed a strong positivity for EC-SOD mRNA while the protein was detected in macrophages and neutrophils. Exposure to hyperoxia did not affect the distribution of EC-SOD mRNA and protein. The presented data demonstrated that in lung tissue the EC-SOD enzyme may have a protective function for activated macrophages, neutrophils, and lympoid tissue-associated epithelial cells.
authors.affiliation: Laboratory of Pharmacology, University of Antwerp (UIA), Antwerpen-Wilrijk, Belgium.
authors.forename: B
authors.initials: B
authors.lastname: Loenders
authors.forename: E
authors.initials: E
authors.lastname: Van Mechelen
authors.forename: S
authors.initials: S
authors.lastname: Nicolaï
authors.forename: N
authors.initials: N
authors.lastname: Buyssens
authors.forename: N
authors.initials: N
authors.lastname: Van Osselaer
authors.forename: P G
authors.initials: PG
authors.lastname: Jorens
authors.forename: J
authors.initials: J
authors.lastname: Willems
authors.forename: A G
authors.initials: AG
authors.lastname: Herman
authors.forename: H
authors.initials: H
authors.lastname: Slegers
mesh_terms: D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D005110:Extracellular Space / Q000201:enzymology; D018496:Hyperoxia / Q000201:enzymology; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007249:Inflammation / Q000201:enzymology / Q000209:etiology / Q000473:pathology; D008070:Lipopolysaccharides / Q000633:toxicity; D008168:Lung / Q000166:cytology / Q000201:enzymology*; D016676:Macrophages, Alveolar / Q000201:enzymology; D008297:Male; D009504:Neutrophils / Q000201:enzymology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013482:Superoxide Dismutase / Q000097:blood / Q000235:genetics / Q000378:metabolism*
chemical_list: D008070:Lipopolysaccharides; D012333:RNA, Messenger; D013482:Superoxide Dismutase