title: Intravital multiphoton fluorescence imaging and optical manipulation of spinal cord in mice, using a compact fiber laser system.
abstract: OBJECTIVE
  Near-infrared ultrafast lasers are widely used for multiphoton excited fluorescence microscopy in living animals. Ti:Sapphire lasers are typically used for multiphoton excitation, but their emission wavelength is restricted below 1,000 nm. The aim of this study is to evaluate the performance of a compact Ytterbium-(Yb-) fiber laser at 1,045 nm for multiphoton excited fluorescence microscopy in spinal cord injury.
  
  
  METHODS
  In this study, we employed a custom-designed microscopy system with a compact Yb-fiber laser and evaluated the performance of this system in in vivo imaging of brain cortex and spinal cord in YFP-H transgenic mice.
  
  
  RESULTS
  For in vivo imaging of brain cortex, sharp images of basal dendrites, and pyramidal cells expressing EYFP were successfully captured using the Yb-fiber laser in our microscopy system. We also performed in vivo imaging of axon fibers of spinal cord in the transgenic mice. The obtained images were almost as sharp as those obtained using a conventional ultrafast laser system. In addition, laser ablation and multi-color imaging could be performed simultaneously using the Yb-fiber laser.
  
  
  CONCLUSIONS
  The high-peak pulse Yb-fiber laser is potentially useful for multimodal bioimaging methods based on a multiphoton excited fluorescence microscopy system that incorporates laser ablation techniques. Our results suggest that microscopy systems of this type could be utilized in studies of neuroscience and clinical use in diagnostics and therapeutic tool for spinal cord injury in the future.
authors.affiliation: Translational Research Center, Ehime University Hospital, Shitsukawa, Toon, Ehime, 791-0295, Japan; Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, 791-0295, Japan; Division of Bio-Imaging Proteo-Scinece Center, Ehime University, Shitsukawa, Toon, Ehime, 791-0295, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Oshima
authors.forename: Hideki
authors.initials: H
authors.lastname: Horiuch
authors.forename: Naoki
authors.initials: N
authors.lastname: Honkura
authors.forename: Atsuhiko
authors.initials: A
authors.lastname: Hikita
authors.forename: Tadanori
authors.initials: T
authors.lastname: Ogata
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Miura
authors.forename: Takeshi
authors.initials: T
authors.lastname: Imamura
mesh_terms: D000818:Animals; D007834:Lasers; D051379:Mice; D008822:Mice, Transgenic; D036641:Microscopy, Fluorescence, Multiphoton; D013119:Spinal Cord Injuries / Q000473:pathology*; D015018:Ytterbium
chemical_list: D015018:Ytterbium
keywords: femtosecond laser; in vivo imaging; laser ablation; microscopy; nonlinear optical imaging; spinal cord injury