title: Lung morphometry and MMP-12 expression in rats treated with intraperitoneal nicotine.
abstract: Nicotine, a toxic tobacco component, plays an important role in the development of cardiovascular and lung diseases in smokers. Our objective was to investigate the effects of the intraperitoneal (i.p.) nicotine treatment in lung morphology. Wistar male rats (3-4 months old) were divided in five groups, a control one, and other groups treated with nicotine (1 mg/kg/day) for 8 days and sacrificed after 24, 48, 96, and 192 h. Morphometry was used to estimate the lung alveolar parenchyme and septal elastic fibers changes, and immunohistochemistry was performed to detect macrophage metalloelastase (MMP-12) and quantify vessels by immunolabelling with alpha-smooth muscle cells. Thickening of the alveolar septa was present in all nicotine groups, and associated with mononuclear cell infiltration, angiogenesis, and irregular areas of collapse. After 96 h, rat lungs showed macrophage, expressing MMP-12, that was also present after 192 h of recovery. Pleural and parenchyma inflammation, fibrosis and macrophage were also seen after 192 h. Intraperitoneal nicotine treated rats exhibited an increase of the volume fraction of alveolar parenchyme, a reduction of volume and surface fraction septal elastic fibers, and an increase of the numerical fraction of microvasculature vessels compared to control ones. MMP-12 was detected in groups of macrophages Wistar rats lung exhibited a progressive morphological damage after 192 hours of recovery, after 8 daily doses of 1 mg/kg body weight on i.p. nicotine.
authors.affiliation: Department of Histology and Embryology, Institute of Biology Roberto Alcantara Gomes, State University of Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Samuel Santos
authors.initials: SS
authors.lastname: Valença
authors.forename: Adenilson
authors.initials: A
authors.lastname: de Souza da Fonseca
authors.forename: Katia
authors.initials: K
authors.lastname: da Hora
authors.forename: Ricardo
authors.initials: R
authors.lastname: Santos
authors.forename: Luis Cristóvão
authors.initials: LC
authors.lastname: Porto
mesh_terms: D000818:Animals; D005731:Ganglionic Stimulants / Q000008:administration & dosage / Q000633:toxicity*; D007274:Injections, Intraperitoneal; D008168:Lung / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D008297:Male; D053508:Matrix Metalloproteinase 12; D008666:Metalloendopeptidases / Q000378:metabolism*; D009538:Nicotine / Q000008:administration & dosage / Q000633:toxicity*; D011650:Pulmonary Alveoli / Q000187:drug effects / Q000473:pathology; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
chemical_list: D005731:Ganglionic Stimulants; D009538:Nicotine; D008666:Metalloendopeptidases; D053508:Matrix Metalloproteinase 12