title: Impairment of nasal airway under intermittent hypoxia during growth period in rats.
abstract: OBJECTIVE
  To clarify the influences of intermittent hypoxia (IH) on the growth and development of the midfacial area, including the nasal cavity, in growing rats.
  
  
  METHODS
  Seven-week-old male Sprague-Dawley rats were divided into two groups: the experimental group (n=5), which was exposed to IH for 8h during light periods at a rate of 20 cycles/h (nadir, 4% O₂ to peak, 21% O₂ with 0% CO₂), and the control group (n=5), which was exposed to room air. After 3 weeks, the maxillofacial structures in both groups were evaluated with respect to the height, width, length, surface area, cross-sectional area, and volume of the nasal cavity using soft X-ray and micro-CT.
  
  
  RESULTS
  The experimental group showed a significantly smaller cross-sectional area and volume than did the control group. The surface area exhibited no significant differences between the two groups, although it tended to be smaller in the experimental group than in the control group. The nasal volume divided by the length of the tibia (for comparison with whole-body growth) was significantly smaller in the experimental group than in the control group.
  
  
  CONCLUSIONS
  These data suggest that IH exposure suppresses growth and development of the nasal cavity and may result in nasal breathing disturbance.
authors: Orthodontic Science, Department of Orofacial Development and Function, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.
authors: Yoichiro
authors: Y
authors: Kuma
authors: Orthodontic Science, Department of Orofacial Development and Function, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.
authors: Risa
authors: R
authors: Usumi-Fujita
authors: Orthodontic Science, Department of Orofacial Development and Function, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan. Electronic address: hosomichi.orts@tmd.ac.jp.
authors: Jun
authors: J
authors: Hosomichi
authors: Orthodontic Science, Department of Orofacial Development and Function, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.
authors: Shuji
authors: S
authors: Oishi
authors: Department of Forensic Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors: Hideyuki
authors: H
authors: Maeda
authors: Department of Forensic Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors: Hisashi
authors: H
authors: Nagai
authors: Orthodontic Science, Department of Orofacial Development and Function, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.
authors: Yasuhiro
authors: Y
authors: Shimizu
authors: Orthodontic Science, Department of Orofacial Development and Function, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.
authors: Sawa
authors: S
authors: Kaneko
authors: Orthodontic Science, Department of Orofacial Development and Function, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.
authors: Chisa
authors: C
authors: Shitano
authors: Department of Advanced Clinical Science and Therapeutics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors: Jun-ichi
authors: J
authors: Suzuki
authors: Department of Forensic Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors: Ken-ichi
authors: K
authors: Yoshida
authors: Orthodontic Science, Department of Orofacial Development and Function, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.
authors: Takashi
authors: T
authors: Ono
mesh_terms: D000818:Animals; D002508:Cephalometry; D000860:Hypoxia / Q000503:physiopathology*; D008297:Male; D009296:Nasal Cavity / Q000000981:diagnostic imaging / Q000254:growth & development*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012891:Sleep Apnea Syndromes / Q000503:physiopathology; D055114:X-Ray Microtomography
keywords: Intermittent hypoxia; Micro-CT; Nasomaxillary complex; Paediatric obstructive sleep apnoea