Expression of heme oxygenase-1 in the lungs of rats exposed to crystalline silica.
Oxidative stress is thought to be the pathogenesis of pulmonary fibrosis induced by particles, and heme oxygenase-1 (HO-1) protects lung tissue against oxidative stress. We hypothesized that HO-1 is also associated with oxidative lung injury caused by exposure to particles. The present study was conducted to investigate the time course of HO-1 expression of lungs exposed to crystalline silica in vivo. Male Wistar rats were administered 1 mg or 2 mg of crystalline silica suspended in saline by a single intratracheal instillation and were sacrificed at 3 d, 1 wk, 1 month, 3 months and 6 months of recovery time. The expression of HO-1 was observed by western blot analysis and immunostaining. Protein levels of HO-1 were increased compared to the controls at 3 d, and from 1 month to 6 months following intratracheal instillation of 2 mg of crystalline silica. The levels of HO-1 were increased compared to the controls from 1 month to 6 months following intratracheal instillation of 1 mg of crystalline silica. Many HO-1 positive cells were found particularly in the alveolar macrophages during immunostaining. These findings suggest that HO-1 is related to lung injury arising from exposure to crystalline silica.
Nagatomo
Hiroko
H
Department of Occupational Pneumology, Institute of Industrial and Ecological Sciences, University of Occupational and Environmental Health, Kitayushu, Japan. nhiroko@me.uoeh-u.ac.jp
Morimoto
Yasuo
Y
Oyabu
Takako
T
Hirohashi
Masami
M
Ogami
Akira
A
Yamato
Hiroshi
H
Kuroda
Kaori
K
Higashi
Toshiaki
T
Tanaka
Isamu
I
D000818:Animals; D015153:Blotting, Western; D051547:Heme Oxygenase-1 / Q000378:metabolism*; D007564:Japan; D008168:Lung / Q000201:enzymology*; D008297:Male; D018384:Oxidative Stress; D051381:Rats; D017208:Rats, Wistar; D012822:Silicon Dioxide / Q000008:administration & dosage / Q000633:toxicity*; D014132:Trachea
D012822:Silicon Dioxide; D051547:Heme Oxygenase-1