Related Experiment Video
Updated: Feb 19, 2026

Studying Chronic Exposure of Mice to Ultraviolet B Radiation
Published on: August 19, 2025
Narrow-band UVB effects on cutaneous vitamin D receptor expression and serum 25-hydroxyvitamin D in generalized
Hala M El-Hanbuli1, Noha M Dawoud2, Rania H Mahmoud3
1Department of Pathology, Faculty of Medicine, Fayoum University, Fayoum, Egypt.
Background/Purpose:
Vitamin D has a role in variety of autoimmune diseases including vitiligo. Narrow-band UVB (NB-UVB) treatment of vitiligo might act through its effects on vitamin D and its receptor.This study is the first to elucidate NB-UVB effects on immunohistochemical vitamin D receptor (VDR) expression in generalized vitiligo and correlate it with serum vitamin D and repigmentation response.
Methods:
Using immunohistochemistry, VDR expression was estimated in skin biopsies of 30 controls and 30 vitiligo patients; from vitiligo lesion, perilesional skin at baseline and from repigmented and nonresponding skin after 24 NB-UVB sessions. Baseline serum 25-hydroxyvitamin D [25(OH)D] was investigated and repeated after 24 NB-UVB sessions.
Results:
Vitamin D receptor expression and serum 25(OH)D in controls were significantly higher compared to vitiligo patients. After NB-UVB therapy, there was a significant rise in VDR expression and serum 25(OH)D. VDR expression was significantly higher in repigmented skin compared to nonresponding lesion. Improvement in the clinical outcome score was associated with higher baseline VDR expression and higher serum 25(OH)D.
Conclusions:
NB-UVB phototherapy is associated with improved cutaneous VDR expression and vitamin D synthesis. Better repigmentation response to NB-UVB may be related to higher baseline VDR expression and its upregulation after phototherapy.
Related Concept Videos
Role of Skin in Vitamin D Synthesis
The solar UV B rays (290-315 nm) are absorbed by the skin, and 7-dehydrocholesterol (provitamin D3) photolyzes it to previtamin D3, which undergoes a rapid transformation to vitamin...
Mutations
Chromosomal Alterations Are Large-Scale Mutations
While point mutations are changes in a single nucleotide in...
Ultraviolet and Visible (UV–Vis) Spectroscopy: Overview
Pigmentation
Melanin occurs in two primary forms: eumelanin that provides black and brown pigment and pheomelanin that provides red color. Dark-skinned individuals produce more melanin than those with pale...
Changes in Skin Color: Clinical Perspectives
Albinism
Albinism is a genetic disorder that affects (completely or partially) the coloring of skin, hair, and eyes. The defect is primarily...
UV–Vis Spectrometers

