title: Topical injury evaluation of the murine colorectal mucosa using confocal endomicrosopy: a valuable method for assessing mucosal injuries associated with risk of pathogen transmission.
abstract: Concern regarding the effect of epithelial damage to the colorectal surface and possible impact on sexually transmitted infection transmission prompts the need for methods to evaluate the mucosal microscopic surface in preclinical studies examining such injury. This includes determining the effect of topical HIV prevention products on mucosal barrier integrity. In vivo imaging with high-resolution endomicroscopy could reveal defects in the mucosal barrier resulting from injury/surface trauma.
  
  
  
  Confocal endomicroscopy was investigated to assess the ability to image surface injury resulting from topical application of a chemical used in lubricants and microbial products. Mice treated with a 50 μL rectal dose of 0.2% benzalkonium chloride solution, 1% benzalkonium chloride or phosphate-buffered saline control for 20 min were imaged in vivo using confocal endomicroscopy for assessment of epithelial disruption. Following imaging, mice were sacrificed and rectal tissue evaluated by histology. Confocal images were graded based on degree of disruption to crypt and epithelial microstructure. Histology was graded based on percent of epithelial disruption observed in stained sections. Confocal image features were confirmed by high-resolution two-photon microscopy.
  
  
  
  Based on quantitative grading of in vivo confocal endomicroscopy images, disruption at the microscopic scale was observed following treatment with benzalkonium chloride, with increased injury occurring with higher dose. Epithelial disruption at the lumen surface, evident between crypts and alteration in crypt structure on the luminal side were observed in confocal endomicroscopy and confirmed by histology.
  
  
  
  High-resolution imaging by confocal endomicroscopy can be used as a noninvasive tool for rapid visual assessment of rectal epithelial integrity following surface injury, potentially providing valuable indication of epithelial injury or trauma.
authors.affiliation: Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas, U.S.A.. grvargas@utmb.edu.|Center for Biomedical Engineering, University of Texas Medical Branch, Galveston, Texas, U.S.A.. grvargas@utmb.edu.
authors.forename: Gracie
authors.initials: G
authors.lastname: Vargas
authors.affiliation: Center for Biomedical Engineering, University of Texas Medical Branch, Galveston, Texas, U.S.A.|Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, Texas, U.S.A.
authors.forename: Kathleen Listiak
authors.initials: KL
authors.lastname: Vincent
authors.affiliation: Center for Biomedical Engineering, University of Texas Medical Branch, Galveston, Texas, U.S.A.
authors.forename: Jingna
authors.initials: J
authors.lastname: Wei
authors.affiliation: Department of Pediatrics, University of Texas Medical Branch, Galveston, Texas, U.S.A.|Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, Texas, U.S.A.
authors.forename: Nigel
authors.initials: N
authors.lastname: Bourne
authors.affiliation: Center for Biomedical Engineering, University of Texas Medical Branch, Galveston, Texas, U.S.A.|Department of Ophthalmology, University of Texas Medical Branch, Galveston, Texas, U.S.A.
authors.forename: Massoud
authors.initials: M
authors.lastname: Motamedi
mesh_terms: D000818:Animals; D001548:Benzalkonium Compounds / Q000633:toxicity; D005260:Female; D015658:HIV Infections / Q000517:prevention & control; D007413:Intestinal Mucosa / Q000000981:diagnostic imaging / Q000187:drug effects / Q000473:pathology*; D051379:Mice; D018613:Microscopy, Confocal / Q000379:methods*; D012007:Rectum / Q000000981:diagnostic imaging / Q000473:pathology*
chemical_list: D001548:Benzalkonium Compounds
keywords: Colorectal; HIV prevention products; confocal endomicroscopy; intravital microscopy; mucosal injury; mucosal trauma; two-photon microscopy