The optical properties of mouse skin in the visible and near infrared spectral regions.
Visible and near-infrared radiation is now widely employed in health science and technology. Pre-clinical trials are still essential to allow appropriate translation of optical methods into clinical practice. Our results stress the importance of considering the mouse strain and gender when planning pre-clinical experiments that depend on light-skin interactions. Here, we evaluated the optical properties of depilated albino and pigmented mouse skin using reproducible methods to determine parameters that have wide applicability in biomedical optics. Light penetration depth (δ), absorption (μa), reduced scattering (μ's) and reduced attenuation (μ't) coefficients were calculated using the Kubelka-Munk model of photon transport and spectrophotometric measurements. Within a broad wavelength coverage (400-1400nm), the main optical tissue interactions of visible and near infrared radiation could be inferred. Histological analysis was performed to correlate the findings with tissue composition and structure. Disperse melanin granules present in depilated pigmented mouse skin were shown to be irrelevant for light absorption. Gender mostly affected optical properties in the visible range due to variations in blood and abundance of dense connective tissue. On the other hand, mouse strains could produce more variations in the hydration level of skin, leading to changes in absorption in the infrared spectral region. A spectral region of minimal light attenuation, commonly referred as the "optical window", was observed between 600 and 1350nm.
Center for Lasers and Applications, Nuclear and Energy Research Institute, IPEN-CNEN/SP, São Paulo, SP, Brazil; Institute for Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil; School of Pharmaceutical Sciences, University of São Paulo, São Paulo, SP, Brazil.
Caetano P
CP
Sabino
Biophotonics Post-Graduation Program, Universidade Nove de Julho, São Paulo, SP, Brazil.
Alessandro M
AM
Deana
Center for Lasers and Applications, Nuclear and Energy Research Institute, IPEN-CNEN/SP, São Paulo, SP, Brazil.
Tania M
TM
Yoshimura
Biophotonics Post-Graduation Program, Universidade Nove de Julho, São Paulo, SP, Brazil.
Daniela F T
DF
da Silva
Biophotonics Post-Graduation Program, Universidade Nove de Julho, São Paulo, SP, Brazil.
Cristiane M
CM
França
Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA; Department of Dermatology, Harvard Medical School, Boston, MA, USA; Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA, USA.
Michael R
MR
Hamblin
Center for Lasers and Applications, Nuclear and Energy Research Institute, IPEN-CNEN/SP, São Paulo, SP, Brazil. Electronic address: marthasr@usp.br.
Martha S
MS
Ribeiro
D000818:Animals; D005260:Female; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D012867:Skin / Q000737:chemistry*; D019265:Spectroscopy, Near-Infrared / Q000379:methods*
Biophotonics; Photodiagnosis; Phototherapy; Radiative transfer; Skin optics; Tissue spectroscopy