title: Repeated formaldehyde inhalation impaired olfactory function and changed SNAP25 proteins in olfactory bulb.
abstract: BACKGROUND
  Formaldehyde inhalation exposure, which can occur through occupational exposure, can lead to sensory irritation, neurotoxicity, mood disorders, and learning and memory impairment. However, its influence on olfactory function is unclear.
  
  
  OBJECTIVE
  To investigate the mechanism and the effect of repeated formaldehyde inhalation exposure on olfactory function.
  
  
  METHODS
  Rats were treated with formaldehyde inhalation (13·5±1·5 ppm, twice 30 minutes/day) for 14 days. Buried food pellet and locomotive activity tests were used to detect olfactory function and locomotion. Western blots were used to evaluate synaptosomal-associated protein 25 (SNAP25) protein levels in the olfactory bulb (OB) lysate and synaptosome, as well as mature and immature olfactory sensory neuron markers, olfactory marker protein (OMP), and Tuj-1. Real-time polymerase chain reaction (PCR) was used to detect SNAP25 mRNA amounts.
  
  
  RESULTS
  Repeated formaldehyde inhalation exposure impaired olfactory function, whereas locomotive activities were unaffected. SNAP25 protein decreased significantly in the OB, but not in the occipital lobe. SNAP25 also decreased in the OB synaptosome when synaptophysin did not change after formaldehyde treatment. mRNA levels of SNAP25A and SNAP25B were unaffected. Mature and immature olfactory sensory neuron marker, OMP, and Tuj-1, did not change after formaldehyde treatment.
  
  
  CONCLUSIONS
  Repeated formaldehyde exposure impaired olfactory function by disturbing SNAP25 protein in the OB.
authors.forename: Qi
authors.initials: Q
authors.lastname: Zhang
authors.forename: Weiqun
authors.initials: W
authors.lastname: Yan
authors.forename: Yang
authors.initials: Y
authors.lastname: Bai
authors.forename: Yingqiao
authors.initials: Y
authors.lastname: Zhu
authors.forename: Jie
authors.initials: J
authors.lastname: Ma
mesh_terms: D000818:Animals; D015153:Blotting, Western; D005557:Formaldehyde / Q000008:administration & dosage / Q000009:adverse effects*; D019570:Inhalation Exposure / Q000009:adverse effects*; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D009830:Olfactory Bulb / Q000737:chemistry* / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction; D012903:Smell / Q000187:drug effects*; D050825:Synaptosomal-Associated Protein 25 / Q000032:analysis*
chemical_list: C494210:Snap25 protein, rat; D050825:Synaptosomal-Associated Protein 25; D005557:Formaldehyde
keywords: Formaldehyde inhalation,; Olfactory function,; SNAP25,; Synaptosome