title: Colorimetry provides a rapid objective measurement of de novo hair growth rate in mice.
abstract: BACKGROUND
  Depilated mice have been used as a test platform for hair growth-regulating agents. However, currently available assessment tools for hair growth in mice are less than ideal.
  
  
  METHODS
  Tristimulus colorimetry of the fur color of depilated agouti, albino, and black mice with L*, a*, and b* values were performed daily until the full growth of pelage. Using light-emitting diode (LED) irradiation (650 and 890 nm) with a daily dose of 3.5 J/cm(2) as hair growth regulators, the hair growth rates observed by the global assessment were compared with those derived from colorimetry.
  
  
  RESULTS
  In contrast to a* and b* values, L* values changed more drastically over time in the anagen phase regardless of fur color. Unlike the inhibitory effect of 650 nm irradiation, LED of 890 nm promoted de novo hair regrowth in mice. The difference in hair growth rates detected by colorimetry paralleled the observation made by the global assessment.
  
  
  CONCLUSIONS
  The L* value of fur color obtained by tristimulus colorimetry was a sensitive yet quantitative indicator of de novo hair growth, and could be used to project the hair growth rate in mice.
authors.affiliation: Department of Dermatology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan. tienyi3@yahoo.com.tw
authors.forename: Tien-Yi
authors.initials: TY
authors.lastname: Tzung
authors.forename: Chia-Yi
authors.initials: CY
authors.lastname: Yang
authors.forename: Yung-Chang
authors.initials: YC
authors.lastname: Huang
authors.forename: Fu-Jen
authors.initials: FJ
authors.lastname: Kao
mesh_terms: D000818:Animals; D003124:Colorimetry / Q000295:instrumentation* / Q000379:methods*; D006197:Hair / Q000254:growth & development*; D006204:Hair Removal; D008027:Light; D008029:Lighting; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D023421:Models, Animal