title: Unilateral maxillary molar extraction influences AQP5 expression and distribution in the rat submandibular salivary gland.
abstract: OBJECTIVE
  Mastication has been regarded as a crucial factor for maintaining the morphology and function of secretion in salivary glands. Although it is known that occlusion affects mastication, the detailed process for how occlusal changes affect the secretory function of salivary glands is still unknown. Aquaporin 5 (AQP5) is a membrane protein that forms water channels, and plays an important role in water transport. In this study, we investigated the structural changes and alterations in the expression and distribution of AQP5 in the rat submandibular salivary gland (SMG) under occlusal hypofunction after unilateral molar extraction.
  
  
  METHODS
  Seven-week-old male Wistar rats (n = 36) were used in the study. In the experimental group, all of the right maxillary molars were extracted. Rats with no molar extraction were used as the control group. The rats were euthanized at 7, 14 or 28 days after the procedure, and the right SMGs were isolated and subjected to histological analyses. The expression and distribution of AQP5 were detected by immunohistochemistry.
  
  
  RESULTS
  Morphological analyses revealed hypertrophic changes in the acinar cells in the experimental group. Immunohistochemical staining of AQP5 was detected in the apical membrane (APM) and intercellular secretory canaliculi of acinar cells in both groups. On the other hand, the AQP5 expression in the APM and intercellular secretory canaliculi of acinar cells was less prominent in the experimental group than in the control group.
  
  
  CONCLUSIONS
  The present findings suggest that unilateral molar extraction has significant influences on the function of water transport in the rat SMG.
authors.affiliation: Orthodontic Science, Department of Orofacial Development and Function, Division of Oral Health Science, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Tokyo 113-8549, Japan. m.mizumachi.orts@tmd.ac.jp
authors.forename: Mariko
authors.initials: M
authors.lastname: Mizumachi-Kubono
authors.forename: Ippei
authors.initials: I
authors.lastname: Watari
authors.forename: Yuji
authors.initials: Y
authors.lastname: Ishida
authors.forename: Takashi
authors.initials: T
authors.lastname: Ono
mesh_terms: D000818:Animals; D051402:Aquaporin 5 / Q000378:metabolism*; D007150:Immunohistochemistry; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism*; D008963:Molar / Q000601:surgery*; D051381:Rats; D017208:Rats, Wistar; D012463:Saliva / Q000378:metabolism*; D013363:Submandibular Gland / Q000166:cytology / Q000378:metabolism*; D014081:Tooth Extraction / Q000009:adverse effects*
chemical_list: D051402:Aquaporin 5; D008565:Membrane Proteins