title: Lymphatic response to depilation-induced inflammation in mouse ear assessed with label-free optical lymphangiography.
abstract: OBJECTIVE
  Optical microangiography (OMAG) is a noninvasive technique capable of imaging 3D microvasculature. OMAG-based optical lymphangiography has been developed for 3D visualization of lymphatic vessels without the need for exogenous contrast agents. In this study, we utilize the optical lymphangiography to investigate dynamic changes in lymphatic response within skin tissue to depilation-induced inflammation by using mouse ear as a simple tissue model.
  
  
  METHODS
  A spectral-domain optical coherence tomography (OCT) system is used in this study to acquire volumetric images of mouse ear. The system operates under the ultrahigh-sensitive OMAG scanning protocol with five repetitions for each B frame. An improved adaptive-threshold-based method is proposed to segment lymphatic vessels from OCT microstructure images. Depilation is achieved by placing hair removal lotion on mouse ear pinna for 5 minutes. Three acquisitions are made before depilation, 3-minute and 30-minute post-depilation, respectively.
  
  
  RESULTS
  Right after the application of depilation lotion on the skin, we observe that the blind-ended sacs of initial lymphatics are mainly visible in a specific area of the normal tissue. At 5 minutes, more collecting lymphatic vessels start to form, evidenced by their valve structure that only exists in collecting lymphatic vessels. The lymphangiogenesis is almost completed within 8 minutes in the inflammatory tissue.
  
  
  CONCLUSIONS
  Our experimental results demonstrate that the OMAG-based optical lymphangiography has great potential to improve the understanding of lymphatic system in response to various physiological conditions, thus would benefit the development of effective therapeutics.
authors.affiliation: Department of Bioengineering, University of Washington, 3720 15th Ave NE, Seattle, Washington 98195-5061.
authors.forename: Wan
authors.initials: W
authors.lastname: Qin
authors.affiliation: Department of Bioengineering, University of Washington, 3720 15th Ave NE, Seattle, Washington 98195-5061.
authors.forename: Utku
authors.initials: U
authors.lastname: Baran
authors.affiliation: Department of Bioengineering, University of Washington, 3720 15th Ave NE, Seattle, Washington 98195-5061.|Department of Ophthalmology, University of Washington, 3720 15th Ave NE, Seattle, Washington 98195-5061.
authors.forename: Ruikang
authors.initials: R
authors.lastname: Wang
mesh_terms: D000818:Animals; D004423:Ear; D006204:Hair Removal / Q000009:adverse effects*; D021621:Imaging, Three-Dimensional / Q000295:instrumentation / Q000379:methods; D007249:Inflammation / Q000209:etiology* / Q000473:pathology; D042601:Lymphatic Vessels / Q000473:pathology*; D008220:Lymphography / Q000295:instrumentation / Q000379:methods; D051379:Mice; D041623:Tomography, Optical Coherence / Q000295:instrumentation / Q000379:methods*
keywords: depilation; lymphatic vasculature; optical coherence tomography; optical lymphangiography; optical microangiography