title: Solar-simulated radiation and heat treatment induced metalloproteinase-1 expression in cultured dermal fibroblasts via distinct pathways: implications on reduction of sun-associated aging.
abstract: BACKGROUND
  Sun exposure is an important environmental factor affecting human beings. Most knowledge regarding solar aging focused on light radiation (photoaging), and little emphasis has been placed on heat, a factor that is also closely associated with sun exposure.
  
  
  OBJECTIVE
  This study was launched to evaluate the effects of simulated solar radiation (SSR) and environmental heat on skin fibroblasts in terms of dermal aging.
  
  
  METHODS
  Cultured human dermal fibroblasts were treated with moderate amount of SSR (200J/cm(2)) and heat (+2°C). The metalloproteinase-1 (MMP-1) expression was used as a surrogate marker for dermal aging and the involved regulatory mechanisms were explored.
  
  
  RESULTS
  Both treatment conditions did not affect viability but significantly increased the expressions of MMP-1. In parallel, both treatments increased the intracellular levels of reactive oxygen species (ROS), but the increase induced by SSR is much greater than heat. In contrast, transient receptor potential vanilloid 1 (TRPV-1), the sensor of environmental heat, was upregulated by heat but not SSR treatment. Pretreating fibroblasts with antioxidant abrogated the SSR-induced MMP-1 but has limited effect on heat-induced MMP-1. On the other hand, TRPV-1 antagonist pretreatment reduced heat-induced MMP-1 in fibroblasts but not their SSR-treated counterparts.
  
  
  CONCLUSIONS
  Both SSR and heat induced MMP-1 expression in dermal fibroblasts but through different pathways. As current strategies for reducing sun-related aging focused on filtering of light and use of antioxidants, future strategies design to reduce solar aging should also incorporate heat-induced aging into consideration.
authors.affiliation: Department of Dermatology, Kaohsiung Medical University Hospital, Department of Dermatology, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Dermatology, Kaohsiung Municipal Ta-Tung Hospital, Kaoshiung Medical University, Kaohsiung, Taiwan. Electronic address: ec_lan@hotmail.com.
authors.forename: Cheng-Che E
authors.initials: CC
authors.lastname: Lan
authors.forename: Ching-Shang
authors.initials: CS
authors.lastname: Wu
authors.forename: Hsin-Su
authors.initials: HS
authors.lastname: Yu
mesh_terms: D002478:Cells, Cultured; D005347:Fibroblasts / Q000201:enzymology / Q000528:radiation effects*; D006358:Hot Temperature / Q000009:adverse effects*; D006801:Humans; D020781:Matrix Metalloproteinase 1 / Q000378:metabolism*; D015595:Skin Aging / Q000528:radiation effects*; D013472:Sunlight / Q000009:adverse effects*
chemical_list: C522360:MMP1 protein, human; D020781:Matrix Metalloproteinase 1
keywords: 8-OHdG; 8-hydroxy-2-deoxyguanosine; DMEM; Dulbecco's minimal essential medium; FACS; Fibroblast; Heat; IR; MFI; MMP-1; N-acetylcysteine; NAC; ROS; RR; SSR; Solar aging; Solar radiation; TRPV-1; TRPV1; UV; fluorescence-activated cell sorting; infrared; mean fluorescence intensity; metalloproteinase-1; reactive oxygen species; ruthenium red; solar simulating radiation; transient receptor potential vanilloid 1; ultraviolet