The effects of UVB and 7, 12, dimethylbenz(alpha)anthracene (DMBA) on epidermal melanocytes of the tail in C57BL mice.

Type:Uv phototherapy Time:2015-03-31 16:58:35

Blog FB, Szabo G.

Abstract

The morphological and numerical changes in the epidermal melanocyte system of the tail of C57BL mice were studied

after exposure to 7, 12 dimethylbenz(alpha)anthracene (DMBA) followed by UVB irradiation. The dorsal aspect of the

tail was exposed for 5 days per week, for a total duration of 10 weeks, to a daily dosage of 0.1 J/cm2 UVB (peak

310 nm). Once a week, 0.2 ml of 0.15% DMBA in acetone was locally applied to the irradiated areas. Biopsies were

studied by the combined skin-splitting DOPA and electron microscopic techniques. After 10 weeks of DMBA treatment

the following changes were observed: DMBA treatment the following changes were observed: the original brick-like

arrangement of melanocytes became confluent, melanocytes were irregularly shaped, dendrites shortened and clumped

together, and the outer root sheaths of the hair follicles became covered with melanocytes. There was a significant

increase in the number of DOPA positive melanocytes at the end of the first week in DMBA and DMBA + UVB treated

skin. Ultrastructurally, an increase in melanosome formation in melanocytes and transfer into keratinocytes was

found, as well as redistribution of melanosomes from singlets and doublets into larger groups. Damage of

melanocytes by the DMBA treatment was seen, but no inflammation or tumor formation was observed.

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