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Updated: Feb 19, 2026
Studying Chronic Exposure of Mice to Ultraviolet B Radiation
Published on: August 19, 2025
The safety and efficacy of light emitting diodes-based ultraviolet A1 phototherapy in bleomycin-induced scleroderma
Diana Karpec1, Romualdas Rudys2, Laima Leonaviciene2
1State Research Institute Centre for Innovative Medicine, Vilnius, Lithuania; The Clinic of Rheumatology, Traumatology Orthopaedics and Reconstructive Surgery, Institute of Clinical Medicine of the Faculty of Medicine of Vilnius University, Vilnius, Lithuania.
Purpose:
To define the efficacy and safety of narrowband ultraviolet A1 (UVA1) for the treatment of dermal fibrosis in bleomycin-induced mouse model of scleroderma.
Materials And Methods:
42 DBA/2 strain mice were included in the study: healthy mice and mice with established scleroderma, treated with high or medium dose of UVA1. Non-treated groups served as control. The equipment emitting 365±5nm UVA1 radiation was used in the study. The average cumulative doses were 1200J/cm2 for high and 600J/cm2 for medium dose course. Histological analysis was performed for the evaluation of the dermal thickness and mast cells density. The expressions of p53 and Ki-67 proteins were assessed by immunohistochemical analyses.
Results:
Skin thickness of mice with scleroderma, treated with high and medium dose of UVA1, were lower (272.9±113.2μm and 394±125.9μm, respectively) in comparison to the dermal thickness of non-treated animals (599±55.7μm). The dermal mast cells count in mice with scleroderma was reduced after high and medium dose treatment to 11±1.7 and 13±2.2, respectively, as compared to that in non-treated mice (23±3.0). No significant upregulation of p53 nor Ki-67 proteins was observed in the skin of healthy mice and mice with scleroderma after high- and medium-dose of UVA1.
Conclusions:
The results of this study indicate that 365nm UVA1 with the cumulative doses of 1200J/cm2 and 600J/cm2 is safe and effective for the dermal fibrosis treatment.
