title: Recovery from silver-nanoparticle-exposure-induced lung inflammation and lung function changes in Sprague Dawley rats.
abstract: In a previous study, the lung function, as indicated by the tidal volume, minute volume, and peak inspiration flow, decreased during 90 days of exposure to silver nanoparticles and was accompanied by inflammatory lesions in the lung morphology. Therefore, this study investigated the recovery from such lung function changes in rats following the cessation of 12 weeks of nanoparticle exposure. Male and female rats were exposed to silver nanoparticles (14-15 nm diameter) at concentrations of 0.66 × 10(6) particles/cm(3) (49 μg/m(3), low dose), 1.41 × 10(6) particles/cm(3) (117 μg/m(3), middle dose), and 3.24 × 10(6) particles/cm(3) (381 μg/m(3), high dose) for 6 h/day in an inhalation chamber for 12 weeks. The rats were then allowed to recover. The lung function was measured every week during the exposure period and after the cessation of exposure, plus animals were sacrificed after the 12-week exposure period, and 4 weeks and 12 weeks after the exposure cessation. An exposure-related lung function decrease was measured in the male rats after the 12-week exposure period and 12 weeks after the exposure cessation. In contrast, the female rats did not show a consistent lung function decrease either during the exposure period or following the exposure cessation. The histopathology showed a gradual recovery from the lung inflammation in the female rats, whereas the male rats in the high-dose group exhibited persistent inflammation throughout the 12-week recovery period. Therefore, the present results suggest a potential persistence of lung function changes and inflammation induced by silver nanoparticle exposure above the no observed adverse effect level.
authors.affiliation: Korea Conformity Laboratory, Incheon, Korea.
authors.forename: Kyung Seuk
authors.initials: KS
authors.lastname: Song
authors.forename: Jae Hyuck
authors.initials: JH
authors.lastname: Sung
authors.forename: Jun Ho
authors.initials: JH
authors.lastname: Ji
authors.forename: Ji Hyun
authors.initials: JH
authors.lastname: Lee
authors.forename: Jong Seong
authors.initials: JS
authors.lastname: Lee
authors.forename: Hyeon Ryol
authors.initials: HR
authors.lastname: Ryu
authors.forename: Jin Kyu
authors.initials: JK
authors.lastname: Lee
authors.forename: Yong Hyun
authors.initials: YH
authors.lastname: Chung
authors.forename: Hyun Min
authors.initials: HM
authors.lastname: Park
authors.forename: Beom Soo
authors.initials: BS
authors.lastname: Shin
authors.forename: Hee Kyung
authors.initials: HK
authors.lastname: Chang
authors.forename: Bruce
authors.initials: B
authors.lastname: Kelman
authors.forename: Il Je
authors.initials: IJ
authors.lastname: Yu
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D005260:Female; D019570:Inhalation Exposure / Q000009:adverse effects; D008168:Lung / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D008297:Male; D053768:Metal Nanoparticles / Q000633:toxicity*; D010316:Particle Size; D010366:Peak Expiratory Flow Rate / Q000187:drug effects; D011014:Pneumonia / Q000139:chemically induced* / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D020127:Recovery of Function; D056152:Respiratory Rate / Q000187:drug effects; D012834:Silver / Q000493:pharmacokinetics / Q000633:toxicity*; D013990:Tidal Volume / Q000187:drug effects; D013997:Time Factors
chemical_list: D012834:Silver