Development of a Near-Infrared Laser Device to Establish a Preliminary Grading Scale for Photothermal Skin Injury in Rodents.
6 affiliations
- 1Shenzhen School of Clinical Medicine, Southern Medical University, Shenzhen, Guangdong, People's Republic of China.
- 2The First School of Clinical Medicine, Southern Medical University, Guangzhou, Guangdong, People's Republic of China.
- 3School of International Education, Southern Medical University, Guangzhou, Guangdong, People's Republic of China.
- 4Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, People's Republic of China.
- 5School of Life Sciences, Sun Yat-sen University, Guangzhou, Guangdong, People's Republic of China.
- 6Department of Radiation Oncology, Shenzhen Hospital, Southern Medical University, Shenzhen, Guangdong, People's Republic of China.
Abstract
Purpose
Studies using animal models of laser-induced photothermal skin injury often report nominal rather than delivered laser output and assess lesions primarily shortly after exposure. A grading system that relates visible lesions to tissue damage throughout repair is also lacking. This study established a model in three rodent species using a characterized 808-nm laser and developed a five-grade scale for longitudinal assessment.Patients and methods
An in-house 808-nm continuous-wave diode laser was characterized by its emission spectrum, beam profile, power linearity across 2-10-W settings, and output stability over 180-s exposures. Female Hartley guinea pigs (n = 4), Sprague-Dawley rats (n = 4), and BALB/c mice (n = 20) were irradiated at a 7-W setting for 180s. Lesions were photographed from 1 h after irradiation to day 28, with histological assessment on days 2, 7, 14, and 28. Three observers independently graded 60 images per species.Results
Delivered power increased linearly across settings (R² = 0.9997). At the 7-W setting, delivered power was 4.63 W, with within-run instability below 0.4%. Gross injury peaked on days 1-2, 2-3, and 3-4 in guinea pigs, rats, and mice, respectively. Lesions in all three species had re-epithelialized by day 28. At 1 h, the proportions of sites with Grade 2 or 3 injury were 58.3%, 75.0%, and 85.0%, respectively. Higher grades corresponded to deeper histological injury. Kendall's W was 0.81-0.90 (all nominal P < 0.001), and mean weighted κ was 0.42-0.49.Conclusion
This study established a photothermal skin injury model in three rodent species using an 808-nm laser with measured, stable output. The preliminary five-grade scale relates gross appearance to histological injury depth and can support longitudinal assessment of injury and repair.
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BibTeX
@article{ning2026development,
title = {{Development of a Near-Infrared Laser Device to Establish a Preliminary Grading Scale for Photothermal Skin Injury in Rodents.}},
author = {Yulu Ning and Yiting Guo and Lakshya Jain and Evan Noel Dympep and Nurhun Baka and Lan Zhang and Qi Wang and Wenyong Tan},
journal = {Clinical, cosmetic and investigational dermatology},
year = {2026},
month = oct,
doi = {10.2147/ccid.s646914},
url = {https://europepmc.org/article/MED/42974052},
note = {CC BY-NC},
}
RIS
TY - JOUR
TI - Development of a Near-Infrared Laser Device to Establish a Preliminary Grading Scale for Photothermal Skin Injury in Rodents.
AU - Yulu Ning
AU - Yiting Guo
AU - Lakshya Jain
AU - Evan Noel Dympep
AU - Nurhun Baka
AU - Lan Zhang
AU - Qi Wang
AU - Wenyong Tan
PY - 2026
DA - 2026/10/28
JO - Clinical, cosmetic and investigational dermatology
DO - 10.2147/ccid.s646914
UR - https://europepmc.org/article/MED/42974052
AB - Purpose Studies using animal models of laser-induced photothermal skin injury often report nominal rather than delivered laser output and assess lesions primarily shortly after exposure. A grading system that relates visible lesions to tissue damage throughout repair is also lacking. This study established a model in three rodent species using a characterized 808-nm laser and developed a five-grade scale for longitudinal assessment.Patients and methods An in-house 808-nm continuous-wave diode laser was characterized by its emission spectrum, beam profile, power linearity across 2-10-W settings, and output stability over 180-s exposures. Female Hartley guinea pigs (n = 4), Sprague-Dawley rats (n = 4), and BALB/c mice (n = 20) were irradiated at a 7-W setting for 180s. Lesions were photographed from 1 h after irradiation to day 28, with histological assessment on days 2, 7, 14, and 28. Three observers independently graded 60 images per species.Results Delivered power increased linearly across settings (R² = 0.9997). At the 7-W setting, delivered power was 4.63 W, with within-run instability below 0.4%. Gross injury peaked on days 1-2, 2-3, and 3-4 in guinea pigs, rats, and mice, respectively. Lesions in all three species had re-epithelialized by day 28. At 1 h, the proportions of sites with Grade 2 or 3 injury were 58.3%, 75.0%, and 85.0%, respectively. Higher grades corresponded to deeper histological injury. Kendall's W was 0.81-0.90 (all nominal P < 0.001), and mean weighted κ was 0.42-0.49.Conclusion This study established a photothermal skin injury model in three rodent species using an 808-nm laser with measured, stable output. The preliminary five-grade scale relates gross appearance to histological injury depth and can support longitudinal assessment of injury and repair.
SN - 1178-7015
ER -