title: Response of lightly and highly pigmented porcine skin (Sus scrofa domestica) to single 3.8-microm laser radiation pulses.
abstract: The purpose of this study was to determine the effect of melanin on skin response to single 3.8-microm, 8-micros laser pulses and the difference in lesion formation thresholds. Our hypothesis was that pigmentation would play a significant role in skin energy absorption at 3.8 microm. Previous studies comparing pigmented and lightly pigmented porcine skin with human skin found that compared with Yorkshire pigs, Yucatan minipigs were a superior model for laser skin exposure because of their higher pigmentation levels. In the current study, 10 pigs under general anesthesia were exposed to 3.8-microm laser pulses ranging from 0.01 J/cm2 to 93 J/cm2. Gross examinations and skin biopsies were done 24 h after laser exposure, and histologic examinations were conducted on these tissue samples. The 24-h effective dose (ED50) was determined to be 4.5 J/cm2 for Yucatan mini-pigs and 2.6 J/cm2 for Yorkshire pigs. As deposited energy was increased, the lesion presentation progressed from desiccation of the superficial layer of epidermis (4 J/cm2) to desiccation with inflammatory centers (14 J/cm2), and finally to replacement of inflammatory areas with an epidermal ulcerated central area (=21 J/cm2). Therefore we found no statistical difference between the 24-h ED50 of the 2 breeds of pigs, nor was there any difference in histologic presentation at 24 h postexposure.
authors.affiliation: Walter Reed Army Medical Center, Washington, DC, and Colorado State University, Department of Environmental and Radiological Health Sciences, Fort Collins, CO, USA.
authors.forename: Anthony C
authors.initials: AC
authors.lastname: Bostick
authors.forename: Deidre E
authors.initials: DE
authors.lastname: Stoffregen
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Johnson
mesh_terms: D000818:Animals; D001706:Biopsy; D004307:Dose-Response Relationship, Radiation; D005260:Female; D007834:Lasers / Q000009:adverse effects*; D008543:Melanins / Q000378:metabolism; D010858:Pigmentation / Q000502:physiology*; D012867:Skin / Q000473:pathology / Q000528:radiation effects*; D013552:Swine; D013556:Swine, Miniature / Q000502:physiology*
chemical_list: D008543:Melanins