title: Adverse effect of nano-silicon dioxide on lung function of rats with or without ovalbumin immunization.
abstract: BACKGROUND
  The great advances of nanomaterials have brought out broad important applications, but their possible nanotoxicity and risks have not been fully understood. It is confirmed that exposure of environmental particulate matter (PM), especially ultrafine PM, are responsible for many lung function impairment and exacerbation of pre-existing lung diseases. However, the adverse effect of nanoparticles on allergic asthma is seldom investigated and the mechanism remains undefined. For the first time, this work investigates the relationship between allergic asthma and nanosized silicon dioxide (nano-SiO₂).
  
  
  RESULTS
  Ovalbumin (OVA)-treated and saline-treated control rats were daily intratracheally administered 0.1 ml of 0, 40 and 80 µg/ml nano-SiO₂ solutions, respectively for 30 days. Increased nano-SiO₂ exposure results in adverse changes on inspiratory and expiratory resistance (Ri and Re), but shows insignificant effect on rat lung dynamic compliance (Cldyn). Lung histological observation reveals obvious airway remodeling in 80 µg/ml nano-SiO₂-introduced saline and OVA groups, but the latter is worse. Additionally, increased nano-SiO₂ exposure also leads to more severe inflammation. With increasing nano-SiO₂ exposure, IL-4 in lung homogenate increases and IFN-γ shows a reverse but insignificant change. Moreover, at a same nano-SiO₂ exposure concentration, OVA-treated rats exhibit higher (significant) IL-4 and lower (not significant) IFN-γ compared with the saline-treated rats. The percentages of eosinophil display an unexpected result, in which higher exposure results lower eosinophil percentages.
  
  
  CONCLUSIONS
  This was a preliminary study which for the first time involved the effect of nano-SiO₂ to OVA induced rat asthma model. The results suggested that intratracheal administration of nano-SiO₂ could lead to the airway hyperresponsiveness (AHR) and the airway remolding with or without OVA immunization. This occurrence may be due to the Th1/Th2 cytokine imbalance accelerated by the nano-SiO₂ through increasing the tissue IL-4 production.
authors.affiliation: Laboratory of Environmental Sciences and Hubei Key Laboratory of Genetic Regulation and Integrative Biology, Huazhong Normal University, Wuhan, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Han
authors.forename: Jing
authors.initials: J
authors.lastname: Guo
authors.forename: Tesfamariam
authors.initials: T
authors.lastname: Abrahaley
authors.forename: Longjuan
authors.initials: L
authors.lastname: Qin
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.forename: Yuduo
authors.initials: Y
authors.lastname: Zheng
authors.forename: Bing
authors.initials: B
authors.lastname: Li
authors.forename: Dandan
authors.initials: D
authors.lastname: Liu
authors.forename: Hanchao
authors.initials: H
authors.lastname: Yao
authors.forename: Jiwen
authors.initials: J
authors.lastname: Yang
authors.forename: Changming
authors.initials: C
authors.lastname: Li
authors.forename: Zhuge
authors.initials: Z
authors.lastname: Xi
authors.forename: Xu
authors.initials: X
authors.lastname: Yang
mesh_terms: D000465:Algorithms; D000818:Animals; D007114:Immunization / Q000009:adverse effects / Q000379:methods; D015847:Interleukin-4 / Q000097:blood; D008168:Lung / Q000187:drug effects* / Q000276:immunology; D008297:Male; D008855:Microscopy, Electron, Scanning; D053758:Nanoparticles / Q000009:adverse effects / Q000737:chemistry; D010047:Ovalbumin / Q000276:immunology*; D051381:Rats; D017208:Rats, Wistar; D012129:Respiratory Function Tests; D012130:Respiratory Hypersensitivity / Q000097:blood / Q000139:chemically induced / Q000276:immunology; D012143:Respiratory Physiological Phenomena / Q000187:drug effects / Q000276:immunology; D012822:Silicon Dioxide / Q000009:adverse effects* / Q000737:chemistry
chemical_list: D015847:Interleukin-4; D012822:Silicon Dioxide; D010047:Ovalbumin