Skin pigmentation after NB‐UVB and three analogues of prostaglandin F2α in guinea pigs: a comparative study

Abstract

Ultraviolet B (UVB) is a well-known modality in increasing skin pigmentation through a variety of proposed mechanisms. Prostaglandin release is one of these mechanisms. Prostaglandin F(2alpha) (PGF(2alpha)) analogues, which are used to control ocular hypertension, were reported to induce periocular skin hyperpigmentation. This study aims to evaluate the local effect of three prostaglandin F(2alpha) analogues, namely Latanoprost, Bimatoprost and Travoprost on skin pigmentation. Assessment of the role of combination with narrow band UVB (NB-UVB) to each of these drugs is evaluated as well. This study involved 18 female adult wild guinea pigs with patchy white and red/brown fur. The hair was shaved from four red/brown areas on the dorsal skin of each animal. In two areas of each animal, one of the above-mentioned drugs was applied alone and in conjunction with NB-UVB. In the other two areas, the vehicle was applied alone and in conjunction with NB-UVB exposure. Skin biopsies from each area were done at the start of the study and 4 weeks after, and stained with haematoxylin and eosin (H&E) and Masson-Fontana (MF) stains. Clinical and histopathological changes were evaluated. Increased pigmentation was found in all areas with PGF(2alpha) analogues with and without NB-UVB. However, the former group had more effect both clinically and histopathologically. PGF(2alpha) analogues are promising drugs in inducing skin pigmentation. This effect can be enhanced with NB-UVB exposure.