Introduction: The melanin – pigment of melanocytes is the primary skin pigment. It determines skin and rat coat coloration. Melanin is distributed throughout the keratinocytes within granules – melanosomes. Synthesis and distribution of melanin are key for dyschromia – discoloration of the skin and different pigment disorders. Thus, melanin is an actual target of the investigation. Unfortunately, as common lab animals, rodents don’t have abundant melanosomes in the epidermis, and because of this, melanin is not visible by its color and requires highlighting.

Aim. To establish a useful method of melanin determination in the rat skin.

Materials and methods: We used 12 rats with dark coats. 5 mm of skin was taken out of the scapular region, fixed with formaldehyde 10%. Melanin staining techniques were used, such as Schmorl’s method (ferrum-based), routine hematoxylineosin, and specific Warthin-Starry (WS) technique, and Fontana-Masson (FM) staining (both silver-based).

Results: Considering translucency of the epidermis and contrasting melanin granules within, we estimated clear look as two scores, visible melanin with interference as 1 score and absented visible melanin as 0 score. So, hematoxylin-eosin got 0, Schmorl’s technique got 1, and a tie of FM and WS techniques got both 2 scores. Thus, FM had a smooth pinkish background of epidermal tissue with sharp, small melanin granules at the germinative layer; WS demonstrated contrasting melanin granules, even more in amount, but a bit less smooth back. Schmorl’s technique displayed melanin less dark and had a significant level of interferences at the same time with darker epidermal coloration.

Conclusions: Routine hematoxylin-eosin staining is useless with melanin detection aim. There are two effective stainings for melanin detection: Fontana-Masson and Warthin-Starry, while Schmorl’s technique is less clear. Silver-based staining procedures are essential in melanin highlighting, and these techniques may be used to visualize melanin metabolism in rat skin.