Short-term exposure to formaldehyde promotes oxidative damage and inflammation in the trachea and diaphragm muscle of adult rats.
Formaldehyde (FA) is an environmental pollutant widely used in industry. Exposure to FA causes irritation of the respiratory mucosa and is associated with inflammation and oxidative stress in the airways. This study aimed at investigating the oxidative effects on the inflammatory response in the trachea and the diaphragm muscle (DM) of rats exposed to different concentrations of formaldehyde. Twenty-eight Fischer male rats were divided into four groups: control group (CG) exposed to the ambient air; and three groups exposed to the following formaldehyde concentrations of 1% (FA1), 5% (FA5) and 10% (FA10), respectively. The exposure occurred for twenty minutes, three times a day for five days. Oxidative stress analyses were performed by carbonyl protein, lipid peroxidation and catalase activity. The assessment of inflammatory cell influx in both organs and the mucus production in the trachea was carried out. There was an increase of lipid peroxidation in the trachea and the DM of FA1 and FA5 groups compared to the CG and FA10. The oxidation of DM proteins increased in FA10 group compared to CG, FA1 and FA5. The catalase enzyme activity in the DM was reduced in FA1, FA5 and FA10 compared to the CG. Meanwhile, there was a reduction in the enzymatic activity of FA10 compared to the CG in the trachea. The morphometric analysis in the DM demonstrated an influx of inflammatory cells in FA10 compared to the CG. In FA10 group, the tracheal epithelium showed metaplasia and ulceration. In addition, the tracheal epithelium showed more mucus deposits in FA5 compared to CG, FA1 and FA10. The results demonstrated that the exposure to formaldehyde at different concentrations in a short period of time promotes oxidative damage and inflammation in the DM and the trachea and causes metaplasia, ulceration and increased mucus at the latter.
Graduating in Medicine, School of Medicine, Federal University of Ouro Preto (UFOP), Ouro Preto, MG, Brazil.
Luiza Fagundes
LF
Lima
Laboratory of Metabolic Biochemistry (LBM), Department of Biological Sciences (DECBI), Center of Research in Biological Sciences (NUPEB), Federal University of Ouro Preto (UFOP), Campus Universitário Morro do Cruzeiro, s/n, Ouro Preto, MG, Brazil.
Giselle Luciane
GL
Murta
Laboratory of Metabolic Biochemistry (LBM), Department of Biological Sciences (DECBI), Center of Research in Biological Sciences (NUPEB), Federal University of Ouro Preto (UFOP), Campus Universitário Morro do Cruzeiro, s/n, Ouro Preto, MG, Brazil.
Ana Carla Balthar
AC
Bandeira
Graduating in Medicine, School of Medicine, Federal University of Ouro Preto (UFOP), Ouro Preto, MG, Brazil.
Clarissa Rodrigues
CR
Nardeli
Laboratory of Morphopathology (LMP), Department of Biological Sciences (DECBI), Center of Research in Biological Sciences (NUPEB), Federal University of Ouro Preto (UFOP), Ouro Preto, MG, Brazil.
Wanderson Geraldo
WG
Lima
Laboratory of Metabolic Biochemistry (LBM), Department of Biological Sciences (DECBI), Center of Research in Biological Sciences (NUPEB), Federal University of Ouro Preto (UFOP), Campus Universitário Morro do Cruzeiro, s/n, Ouro Preto, MG, Brazil. Electronic address: franksbezerra@hotmail.com.
Frank Silva
FS
Bezerra
D000818:Animals; D002374:Catalase / Q000378:metabolism; D003964:Diaphragm / Q000201:enzymology / Q000378:metabolism / Q000473:pathology*; D004305:Dose-Response Relationship, Drug; D004785:Environmental Pollutants / Q000032:analysis / Q000633:toxicity*; D005557:Formaldehyde / Q000032:analysis / Q000633:toxicity*; D007249:Inflammation / Q000139:chemically induced* / Q000378:metabolism / Q000473:pathology*; D015227:Lipid Peroxidation / Q000187:drug effects; D008297:Male; D009093:Mucus / Q000187:drug effects / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects*; D050050:Protein Carbonylation / Q000187:drug effects; D051381:Rats; D011916:Rats, Inbred F344; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D014136:Tracheitis / Q000139:chemically induced* / Q000378:metabolism / Q000473:pathology*
D004785:Environmental Pollutants; D017392:Thiobarbituric Acid Reactive Substances; D005557:Formaldehyde; D002374:Catalase
Diaphragm muscle; Formaldehyde; Inflammation; Oxidative damage; Respiratory system; Trachea