title: Effects of (-)-epigallocatechin-3-gallate on expression of matrix metalloproteinase-1 and tissue inhibitor of metalloproteinase-1 in fibroblasts irradiated with ultraviolet A.
abstract: BACKGROUND
  It is known that ultraviolet irradiation can affect cellular function through a number of signaling pathways. (-)-epigallocatechin-3-gallate (EGCG) is the major effective component in green tea and can offer protection from ultraviolet-induced damage. In this study, we investigated the protective mechanism of EGCG on human dermal fibroblasts damaged by ultraviolet A (UVA) in vitro.
  
  
  METHODS
  Transcription factor Jun protein levels were measured by Western blot. Matrix metalloproteinase 1 (MMP-1) and tissue inhibitor of metalloproteinase-1 (TIMP-1) mRNA were studied by reverse transcription-polymerase chain reaction (RT-PCR) analysis in conjunction with computer-assisted image analysis. MMP-1 and TIMP-1 proteins were quantified by enzyme-linked immunosorbent assay (ELISA).
  
  
  RESULTS
  EGCG decreased transcription activity of Jun protein after induction by UVA. Both the mRNA and protein levels of MMP-1 were increased by UVA irradiation, while no significant changes were observed in TIMP-1 levels. The ratio of MMP-1 to TIMP-1 showed statistically significant differences compared with the control. EGCG decreased the ratio of MMP-1 to TIMP-1 by inhibiting UVA-induced MMP-1 expression (P < 0.05).
  
  
  CONCLUSIONS
  EGCG can protect human fibroblasts against UVA damage by downregulating the transcription activity of Jun protein and the expression of MMP-1. The ratio of MMP-1 to TIMP-1, rather than the levels of MMP-1 or TIMP-1 alone, may play a significant role in human skin photodamage.
authors.affiliation: Department of Dermatology, First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China.
authors.forename: Xiu-zu
authors.initials: XZ
authors.lastname: Song
authors.forename: Ji-ping
authors.initials: JP
authors.lastname: Xia
authors.forename: Zhi-gang
authors.initials: ZG
authors.lastname: Bi
mesh_terms: D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology*; D002478:Cells, Cultured; D005347:Fibroblasts / Q000378:metabolism / Q000528:radiation effects; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D020781:Matrix Metalloproteinase 1 / Q000096:biosynthesis / Q000235:genetics*; D016755:Proto-Oncogene Proteins c-jun / Q000032:analysis; D012333:RNA, Messenger / Q000032:analysis; D011837:Radiation-Protective Agents / Q000494:pharmacology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000096:biosynthesis / Q000235:genetics*; D014466:Ultraviolet Rays
chemical_list: D016755:Proto-Oncogene Proteins c-jun; D012333:RNA, Messenger; D011837:Radiation-Protective Agents; D019715:Tissue Inhibitor of Metalloproteinase-1; D002392:Catechin; C045651:epigallocatechin gallate; D020781:Matrix Metalloproteinase 1