The Study of Serial Histochemical Changes in Laser-related Post-inflammatory Hyperpigmentation

Alternative Title
송효상
Author(s)
Song, Hyo Sang
Alternative Author(s)
송효상
Advisor
강희영
Department
일반대학원 의학과
Publisher
The Graduate School, Ajou University
Publication Year
2013-02
Language
eng
Keyword
Q-switched Alexandrite laser
Alternative Abstract
Post-inflammatory pigmentary changes are frequently encountered problems of laser treatment. However, their underlying mechanisms and pathogenesis are not fully understood. To elucidate how melanocyte-specific proteins and paracrine melanogenic factors are regulated by laser surgery, time-sequential immunohistochemical studies were performed with Q-switched alexandrite laser (QSL)-irradiated skin of four healthy subjects. Skin biopsies were performed at baseline first and then immediately, 2, 7 and 21 or 28 days after the irradiation. Topical corticosteroid was applied to one subject immediately after laser irradiation and thereafter to investigate its effect preventing laser-induced post-inflammatory changes. Hematoxylin and eosin staining showed vacuolar change on the basal layer and dermal edema immediately after irradiation, which were fully recovered over 28 days. Fontana-Masson staining showed that melanin pigment was removed and detected on the corneal layer as extracellular melanin. At day 28, either hyperpigmentation or hypopigmentation was observed, while interestingly, no definite alteration was seen in the subject treated with corticosteroid. Immunohistochemical staining with melanocytic markers including NKI/beteb, microphthalmia-associated transcription factor and tyrosinase demonstrated that melanocytes appeared to be destroyed but a few cells were preserved immediately after the laser irradiation. The expressions of melanogenesis-associated proteins were increased at day 7 and sustained until day 28. Time-sequential expressions of paracrine melanogenic factors including heat shock protein-70 (hsp-70), tumor necrosis factor-alpha (TNF-α), endothelin-1 (ET-1), alpha-melanocyte stimulating hormone (α-MSH), cyclooxygenase-1 (COX-1), COX-2, vascular endothelial growth factor and stem cell factor (SCF) were also investigated. The expressions of hsp-70 and TNF-α were decreased after the irradiation and recovered within 28 days. The expressions of VEGF were increased immediately after the irradiation in the dermis. The expressions of α-MSH, COX-1, COX-2, ET-1, and SCF revealed to be variable without a consistent pattern. All above changes were minimal in the subjective treated with corticosteroids. In conclusion, the melanocytes were preserved despite a strong injury on the basal layer. The melanogenic action was activated at day 7 and sustained until day 28 regardless final pigmentary changes. The changes in expressions of hsp 70, TNF-α and VEGF might to be related to the laser-induced melanocyte activation. Topical corticosteroids seem to play a protective role against above changes.
URI
https://dspace.ajou.ac.kr/handle/2018.oak/18201
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Graduate School of Ajou University > Department of Medicine > 3. Theses(Master)
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