title: Monitoring vaginal epithelial thickness changes noninvasively in sheep using optical coherence tomography.
abstract: OBJECTIVE
  High-resolution optical coherence tomography can be used noninvasively to evaluate vaginal morphologic features, including epithelial thickness, to assess this protective barrier in transmission of sexually transmitted infections and to monitor tissue response to topical medications and hormonal fluctuations. We examined the use of optical coherence tomography to measure epithelial thickness noninvasively before and after topical treatment with a drug that causes epithelial thinning.
  
  
  METHODS
  Twelve female sheep were treated with intravaginal placebo (n = 4) or nonoxynol-9 (n = 8). Vaginal optical coherence tomography images were obtained before and 24 hours after treatment. Four sheep in the nonoxynol-9 group were also examined on days 3 and 7. Vaginal biopsies were obtained on the last examination day. Epithelial thickness was measured in optical coherence tomography images and in hematoxylin and eosin-stained histologic sections from biopsies. Statistical analysis was performed using analyses of variance (significance P < .05).
  
  
  RESULTS
  Baseline optical coherence tomography epithelial thickness measurements were similar (85 ± 19 μm placebo, 78 ± 20 μm nonoxynol-9; P = .52). Epithelial thinning was significant after nonoxynol-9 (32 ± 22 μm) compared with placebo (80 ± 15 μm) 24 hours after treatment (P < .0001). In the 4 nonoxynol-9-treated sheep followed for 7 days, epithelial thickness returned to baseline by day 3, and increased significantly on day 7. Epithelial thickness measurements from histology were not significantly different than optical coherence tomography (P = .98 nonoxynol-9, P = .93 hydroxyethyl cellulose).
  
  
  CONCLUSIONS
  Drug-induced changes in the epithelium were clearly detectable using optical coherence tomography imaging. Optical coherence tomography and histology epithelial thickness measurements were similar, validating optical coherence tomography as a noninvasive method for epithelial thickness measurement, providing an important tool for quantitative and longitudinal monitoring of vaginal epithelial changes.
authors: Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, TX, USA. klvincen@utmb.edu
authors: Kathleen L
authors: KL
authors: Vincent
authors: Gracie
authors: G
authors: Vargas
authors: Jingna
authors: J
authors: Wei
authors: Nigel
authors: N
authors: Bourne
authors: Massoud
authors: M
authors: Motamedi
mesh_terms: D000282:Administration, Intravaginal; D000818:Animals; D004848:Epithelium / Q000187:drug effects* / Q000473:pathology; D005260:Female; D017137:Nonoxynol / Q000008:administration & dosage / Q000494:pharmacology*; D012756:Sheep; D013089:Spermatocidal Agents / Q000008:administration & dosage / Q000494:pharmacology*; D041623:Tomography, Optical Coherence; D014621:Vagina / Q000187:drug effects* / Q000473:pathology
chemical_list: D013089:Spermatocidal Agents; D017137:Nonoxynol