Menezes MCS, Buzelin M, Nunes CB, Alberti LR. Tacrolimus action pathways in an ointment base for hypertrophic scar prevention in a rabbit ear model.
An Bras Dermatol 2021;
96:429-435. [PMID:
34006401 PMCID:
PMC8245727 DOI:
10.1016/j.abd.2020.08.019]
[Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 08/13/2020] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND
Tacrolimus is used to prevent unaesthetic scars due to its action on fibroblast activity and collagen production modulation.
OBJECTIVES
To evaluate the action pathways, from the histopathological point of view and in cytokine control, of tacrolimus ointment in the prevention of hypertrophic scars.
METHODS
Twenty-two rabbits were submitted to the excision of two 1-cm fragments in each ear, including the perichondrium. The right ear received 0.1% and 0.03% tacrolimus in ointment base twice a day in the upper wound and in the lower wound respectively. The left ear, used as the control, was treated with petrolatum. After 30 days, collagen fibers were evaluated using special staining, and immunohistochemistry analyses for smooth muscle actin, TGF-β and VEGF were performed.
RESULTS
The wounds treated with 0.1% tacrolimus showed weak labeling and a lower percentage of labeling for smooth muscle actin, a higher proportion of mucin absence, weak staining, fine and organized fibers for Gomori's Trichrome, strong staining and organized fibers for Verhoeff when compared to controls. The wounds treated with 0.03% tacrolimus showed weak labeling for smooth muscle actin, a higher proportion of mucin absence, strong staining for Verhoeff when compared to the controls. There was absence of TGF-β and low VEGF expression.
STUDY LIMITATIONS
The analysis was performed by a single pathologist. Second-harmonic imaging microscopy was performed in 2 sample areas of the scar.
CONCLUSIONS
Both drug concentrations were effective in suppressing TGF-β and smooth muscle actin, reducing mucin, improving the quality of collagen fibers, and the density of elastic fibers, but only the higher concentration influenced elastic fiber organization.
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