Protective effects of EGCG on UVB-induced damage in living skin equivalents.
In this study, we evaluate the effects of (-)-epigallocatechin-3-gallate (EGCG) on ultraviolet B (UVB)-irradiated living skin equivalents (LSEs). Histologically, UVB irradiation induced thinning of the LSE epidermis, whereas EGCG treatment led to thickening of the epidermis. Moreover, EGCG treatment protected LSEs against damage and breakdown caused by UVB exposure. Immunohistochemically, UVB-exposed LSEs expressed p53, Fas, and 8-hydroxy-deoxyguanosine (8-OHdG), all of which are associated with apoptosis. However, EGCG treatment reduced the levels of UVB-induced apoptotic markers in the LSEs. In order to determine the signaling pathways induced by UVB, Western blot analysis was performed for both c-Jun NH2-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK), which are associated with UVB-induced oxidative stress. UVB activated JNK in the epidermis and dermis of the LSEs, and EGCG treatment reduced the UVB-induced phosphorylation of JNK. In addition, p38 MAPK was also found to have increased in the UVB-exposed LSEs. Also, EGCG reduced levels of the phosphorylation of UVB-induced p38 MAPK. In conclusion, pretreatment with EGCG protects against UVB irradiation via the suppression of JNK and p38 MAPK activation. Our results suggest that EGCG may be useful in the prevention of UVB-induced human skin damage, and LSEs may constitute a potential substitute for animal and human studies.
Kim
So-Young
SY
Department of Dermatology, Seoul National University College of Medicine, Seoul 110-744, Korea.
Kim
Dong-Seok
DS
Kwon
Sun-Bang
SB
Park
Eun-Sang
ES
Huh
Chang-Hun
CH
Youn
Sang-Woong
SW
Kim
Suk-Wha
SW
Park
Kyoung-Chan
KC
D017209:Apoptosis / Q000187:drug effects* / Q000528:radiation effects; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology; D002478:Cells, Cultured; D004249:DNA Damage / Q000187:drug effects; D005347:Fibroblasts; D006801:Humans; D015603:Keratinocytes; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000528:radiation effects; D011832:Radiation Injuries / Q000517:prevention & control; D011837:Radiation-Protective Agents / Q000494:pharmacology*; D012867:Skin / Q000187:drug effects* / Q000473:pathology / Q000528:radiation effects; D023822:Tissue Engineering; D014466:Ultraviolet Rays
D011837:Radiation-Protective Agents; D002392:Catechin; C045651:epigallocatechin gallate