title: Gastroesophageal reflux and eustachian tube dysfunction in an animal model.
abstract: OBJECTIVE
  To explore the possible relationship between gastroesophageal reflux and eustachian tube dysfunction in an animal model.
  
  
  METHODS
  Randomized trial.
  
  
  METHODS
  Twenty Sprague-Dawley rats were randomly assigned into two groups, the control (phosphate-buffered saline, n = 10) and experimental (hydrochloric acid [HCl]/pepsin, n = 10) groups. All rats underwent an operation to implant a polyethylene tube into the posterior nasopharynx, through which phosphate-buffered solution or simulated gastric juice (0.5 mg/mL pepsin in 0.01 HCl) was infused at a rate of 0.1 mL/h for 2 0 minutes three times a day for 7 days. Passive opening pressure (POP), passive closing pressure (PCP), active clearance of positive pressure (ACPP) and active clearance of negative pressure (ACNP) were measured before catheter implantation, on postoperative day 5, and after days 1, 3, 5, and 7 of infusion. Mucociliary clearance time (MCCT) was measured after day 7 of infusion. Statistical analysis used a two-way analysis of variance (POP, PCP, ACPP, and ACNP) and Mann-Whitney rank sum test (MCCT).
  
  
  RESULTS
  Significant increases in POP (P = .004), PCP (P <.001), ACPP (P <.001), ACNP (P <.001), and MCCT (P <.001) were demonstrated in the HCl/pepsin group compared with the control group. No significant difference was seen between preoperative and postoperative values.
  
  
  CONCLUSIONS
  Nasopharyngeal exposure to simulated gastric juice causes eustachian tube dysfunction in rats. Specifically, middle ear pressure regulation and mucociliary clearance of middle ear contents were disabled. These results support recent reports in the literature linking nasopharyngeal reflux to eustachian tube dysfunction and secondary development of otitis media.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, University of North Carolina, Chapel Hill, USA. david_white@med.unc.edu
authors.forename: David R
authors.initials: DR
authors.lastname: White
authors.forename: S Brett
authors.initials: SB
authors.lastname: Heavner
authors.forename: Stuart M
authors.initials: SM
authors.lastname: Hardy
authors.forename: Jiri
authors.initials: J
authors.lastname: Prazma
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004427:Ear Diseases / Q000209:etiology; D005064:Eustachian Tube / Q000502:physiology; D005764:Gastroesophageal Reflux / Q000150:complications*; D009079:Mucociliary Clearance / Q000502:physiology; D010033:Otitis Media / Q000209:etiology; D011312:Pressure; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley