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Published on: June 1, 2017
A new morphometric technique for assessment of melanization in skin of guinea pigs
Tag S Anbar1, Tarek S El-Ammawi, Manal T Barakat
1Dermatology Department, Al- Minya University, Al- Minya, Egypt. taganbar@yahoo.com
Background:
The degree of melanization is an important finding in many skin disorders. An objective measurement of melanin density is needed to achieve an accurate evaluation.
Objectives:
The present work aims at translating the subjective increase of melanin particles after narrow band ultraviolet-B (NB-UVB) irradiation into objective numerical values ready for statistical analysis.
Materials And Methods:
This study had involved 18 guinea pigs that were exposed to biweekly sessions of NB-UVB radiation for 4 weeks to induce skin pigmentation. Two skin biopsies were obtained from each animal; the first before treatment and the second at the end of the study, using 5 mm punch and stained with hematoxylin and eosin and Masson-Fontana (MF) stains. Surface area of both the epidermis (ESA) and the melanin particles (MPSA) were measured in μm(2) using a software supplied with Olympus light microscope. The MPSA/ESA percentage was calculated for each biopsy. The results before and after NB-UVB exposure were compared and statistically analyzed.
Results:
In the MF-stained sections, the mean ± SD of the MPSA/ESA percentage were 0.24 μm(2) ± 0.09 and 6.21 μm(2) ± 2.45 at the start of the study and at its end, respectively, with a highly significant difference (P < 0.001).
Conclusion:
This technique offers a new methodology for an accurate numerical evaluation of epidermal melanization.
