title: Intravital Fluorescence Excitation in Whole-Animal Optical Imaging.
abstract: Whole-animal fluorescence imaging with recombinant or fluorescently-tagged pathogens or cells enables real-time analysis of disease progression and treatment response in live animals. Tissue absorption limits penetration of fluorescence excitation light, particularly in the visible wavelength range, resulting in reduced sensitivity to deep targets. Here, we demonstrate the use of an optical fiber bundle to deliver light into the mouse lung to excite fluorescent bacteria, circumventing tissue absorption of excitation light in whole-animal imaging. We present the use of this technology to improve detection of recombinant reporter strains of tdTomato-expressing Mycobacterium bovis BCG (Bacillus Calmette Guerin) bacteria in the mouse lung. A microendoscope was integrated into a whole-animal fluorescence imager to enable intravital excitation in the mouse lung with whole-animal detection. Using this technique, the threshold of detection was measured as 103 colony forming units (CFU) during pulmonary infection. In comparison, the threshold of detection for whole-animal fluorescence imaging using standard epi-illumination was greater than 106 CFU.
authors.affiliation: Department of Biomedical Engineering, Texas A&M University, College Station, Texas, United States of America.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Nooshabadi
authors.affiliation: Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, Bryan, Texas, United States of America.
authors.forename: Hee-Jeong
authors.initials: HJ
authors.lastname: Yang
authors.affiliation: Department of Biomedical Engineering, Texas A&M University, College Station, Texas, United States of America.
authors.forename: Joel N
authors.initials: JN
authors.lastname: Bixler
authors.affiliation: Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, Bryan, Texas, United States of America.
authors.forename: Ying
authors.initials: Y
authors.lastname: Kong
authors.affiliation: Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, Bryan, Texas, United States of America.
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Cirillo
authors.affiliation: Department of Biomedical Engineering, Texas A&M University, College Station, Texas, United States of America.
authors.forename: Kristen C
authors.initials: KC
authors.lastname: Maitland
mesh_terms: D000818:Animals; D005260:Female; D005453:Fluorescence; D008168:Lung / Q000382:microbiology; D051379:Mice; D009163:Mycobacterium bovis / Q000502:physiology; D061848:Optical Imaging / Q000379:methods*