Accumulation of FITC near stratum corneum-visualizing epidermal distribution of a strong sensitizer using two-photon microscopy

• Background The allergenic potency of a hapten is related to its skin penetration properties, but little is known about the distribution of haptens in the skin following topical application. Objectives The aim of this study was to investigate the diffusion and epidermal distribution using two-photon microscopy (TPM) of two fluorescent compounds. Methods Sensitizing capacities of fluorescein isothiocyanate (FITC) and fluorescein were investigated using the local lymph node assay. Chemical reactivity of the compounds was analysed, and their distribution in human epidermis was visualized using TPM and confocal microscopy. Also the in vitro diffusion through epidermis of FITC and fluorescein has been examined. Results FITC was classified as an extreme sensitizer, whereas fluorescein was non-sensitizing. TPM and confocal microscopy showed an accumulation of FITC in stratum corneum (SC), whereas fluorescein was more evenly distributed in epidermis. The diffusion of fluorescein through epidermis was three times higher than that of FITC. Conclusions TPM, which has never been used in this context before, is a promising tool for visualizing the distribution of fluorescent compounds of varying reactivity in intact skin. The strong allergen FITC is mainly retained in or adjacent to SC, whereas most fluorescein diffused through the epidermis.

Ämnesord

NATURVETENSKAP  -- Kemi -- Organisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Organic Chemistry (hsv//eng)

NATURVETENSKAP  -- Kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences (hsv//eng)

Nyckelord

contact allergy

FITC

fluorescent hapten

laser scanning confocal

microscopy

local lymph node assay

skin penetration

two-photon

microscopy

lymph-node assay

allergic contact-dermatitis

in-vitro

skin

sensitization

peptide reactivity

fluorescein isothiocyanate

classification

dinitrochlorobenzene

phenylisothiocyanate

hypersensitivity

local lymph node assay

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)