Assessment of the effect of narrowband UVB and broadband UVB on mice skin using optical coherence tomography

Abstract

Ultraviolet B (UVB) has been used in dermatological phototherapy widely. Narrowband UVB (NB-UVB), with a peak at 311nm, is considered more effective than broadband UVB (BB-UVB). However, the safety of NB-UVB is controversial. Optical coherence tomography (OCT), a novel, non-invasive and depth-resolved imaging technology, is a useful tool for detection of the skin structure <i>in vivo</i>. This study assessed the effect of NB-UVB and BB-UVB on the skin using OCT for the first time. In this study, Balb/c mouse model was surveyed by an OCT system with 1310 nm central wavelength. The two UVB sources were applied on mice dorsal skin with equal biological doses. Mice skin were exposed with increasing UVB doses (1MED, 3MEDs and 5MEDs), OCT images of UVB induced skin tissues were obtained 48h later. The experimental results indicated that, the changes of NB-UVB induced skin tissues (increase in stratum corneum, crust formation, increase of penetration depth of the light and erythema/edema response) are similar to that of BB-UVB induced skin tissues at low and moderate UVB doses. However, the skin tissues exposed with 5MEDs NB-UVB suffered from more lesions than BB-UVB induced skin tissues. In conclusion, potential risk should be considered before NB-UVB phototherapy. Optimized treatment times and frequency as well as close clinical monitoring (e.g., using OCT to real-time monitor the lesions) should be taken to reduce the latent risk of NB-UVB phototherapy.