title: Morphologic Changes of Zebrafish Melanophore after Intense Pulsed Light and Q-Switched Nd:YAG Laser Irradiation.
abstract: BACKGROUND
  Recently, the pulse-in-pulse mode of intense pulsed light (IPL) has been used increasingly for the treatment of melasma.
  
  
  OBJECTIVE
  To observe the morphologic changes in the melanophore in adult zebrafish after irradiation with conventional and pulse-in-pulse IPL and Q-switched Nd:YAG (QSNY) laser.
  
  
  METHODS
  Adult zebrafish were irradiated with conventional and pulse-in-pulse mode of IPL. The conditions for conventional IPL were 3 mJ/cm2, 560 nm filter, and pulse widths of 7, 20, and 35 msec. The pulse-in-pulse conditions were 3 mJ/cm2and on-time 1/off-time 2. The QSNY laser was used with the settings of 1,064 nm, 0.4 J/cm2, a 7 mm spot size, and one shot. Specimens were observed using a light microscope, a transmission electron microscope (TEM), a scanning electron microscope (SEM) and a confocal microscope.
  
  
  RESULTS
  After conventional IPL irradiation with a 7 msec pulse width, melanophore breakage was observed using light microscopy. Under TEM, irradiation with conventional IPL for 7 msec and pulse-in-pulse IPL induced melanophore thermolysis with vacuolization. However, changes in the melanophore were not observed with 35 msec IPL. Under SEM, unlike the control and QSNY groups, IPL-irradiated zebrafish showed finger-like fusion in the protein structure of scales. Specimens examined by a confocal microscope after conventional IPL irradiation showed a larger green-stained area on TUNEL staining than that after pulse-in-pulse mode IPL irradiation.
  
  
  CONCLUSIONS
  Zebrafish irradiated with long pulse-IPL showed no morphologic changes using light microscopy, while morphological changes in melanophores were evident with use of TEM. Pulse-in-pulse mode IPL caused less damage than conventional IPL.
authors.affiliation: Department of Dermatology, Korea University College of Medicine, Seoul, Korea.
authors.forename: Hwa Jung
authors.initials: HJ
authors.lastname: Ryu
authors.affiliation: Department of Dermatology, Korea University College of Medicine, Seoul, Korea.
authors.forename: Ji Min
authors.initials: JM
authors.lastname: Lee
authors.affiliation: Department of Dermatology, Korea University College of Medicine, Seoul, Korea.
authors.forename: Hee Won
authors.initials: HW
authors.lastname: Jang
authors.affiliation: Laboratory of Neurodevelopmental Genetics, Graduate School of Medicine, Korea University, Seoul, Korea.
authors.forename: Hae Chul
authors.initials: HC
authors.lastname: Park
authors.affiliation: Department of Anatomy, Korea University College of Medicine, Seoul, Korea.
authors.forename: Im Joo
authors.initials: IJ
authors.lastname: Rhyu
authors.affiliation: Department of Dermatology, Korea University College of Medicine, Seoul, Korea.
authors.forename: Il-Hwan
authors.initials: IH
authors.lastname: Kim
keywords: Intense pulsed light; Melanophores; Zebrafish