Study of 1550-nm Erbium glass laser fractional non-ablative treatment of photoaging: Comparative clinical effects, histopathology, electron microscopy, and immunohistochemistry

Abstract

Background: Non-ablative fractional lasers have been effectively used in skin rejuvenation. Objectives: This study evaluates the efficacy of 1550-nm Erbium glass laser for facial rejuvenation through the correlation of clinical evaluation and histopathology, immunohistochemistry, and electron microscopy analysis. Methods: Fifteen subjects (average age: 56.4 years, skin types: I–III) with mild-to-moderate photodamage were submitted to biopsies and 3 facial treatments. Data from the photo assessments and the clinical improvement were analyzed 4 months after the treatments. The biopsy skins were fixed in neutral buffered formalin before being embedded in paraffin, and stained with hematoxylin and eosin. The histomorphometric quantification of collagen and elastic fibers; intercellular adhesion molecule 1 expression by immunohistochemistry; and analysis of cell cycle phases, the electrical potential of the mitochondrial, and interleukin (IL)-1, CD34, transforming growth factor (TGF)-β, and caspase-3 expression by flow cytometry were analyzed. Results: After 4 months of treatment, collagen fibers had increased by 6.68%, and intercellular adhesion molecule 1 (ICAM-1) had increased by 4.47% in vessel area. Significantly enhanced IL-1 and TGF-β receptor expressions were identified after treatment. Proliferative responses and non-apoptosis-dependent caspase-3 activity were both observed in the cell after dermal treatment. Conclusion: The histopathology, immunohistochemistry, and electron microscopy showed an improvement compatible to the clinical effectiveness after 4 months.