Effects of intense pulsed light and ultraviolet A on metalloproteinases and extracellular matrix expression in human skin.
OBJECTIVE
The aim of this study was to evaluate the effects of intense pulsed light (IPL) and ultraviolet A (UVA) irradiation on the expression of matrix metalloproteases (MMPs), tissue inhibitor of metalloproteinase 1 (TIMP-1), and extracellular matrix (ECM) in human skin, and to confirm the relative mechanism.


BACKGROUND
IPL has been widely used to treat photoaged skin but the underlying mechanism remains unknown.


METHODS
Human buttock skin was irradiated by repetitive suberythemal doses of UVA and therapeutic doses of IPL. Skin biopsies were taken and the protein/mRNA expression of MMP-1, -3, -9, and -12 and TIMP-1 was examined by immunohistochemistry, image analysis, and real-time quantitative polymerase chain reaction (qRT-PCR).


RESULTS
Compared with normal control skin, both IPL and UVA irradiation induced a general elevation of MMP-1, -3, -9, and -12 and TIMP-1 at protein/mRNA levels, with some differences in the MMP expression patterns, e.g., a remarkable increase of MMP-1, -3, and -12 in UVA-exposed skin, while lower MMP-1, -3, and -12 (p < 0.01, p < 0.01, p < 0.01) but higher MMP-9 (p < 0.05) levels in IPL-irradiated skin. Meanwhile, increased collagen I fibers (p < 0.05) were observed in IPL-irradiated skin, whereas fragments of elastic fibers were found in UVA-exposed skin.


CONCLUSIONS
These findings demonstrated that IPL has similar effects on the expression of MMPs/TIMP-1 in human skin to UVA, but the expression pattern differed from that in UVA-exposed skin, which may account for IPL's photorejuvenation effects.
Department of Dermatology, Xijing Hospital, The Fourth Military Medical University, Xi'an, China.
Weijie
W
Gu
Wei
W
Liu
Xueqin
X
Yang
Xiaozhong
X
Zhao
Xiaoying
X
Yuan
Huimin
H
Ma
Yan
Y
Tian
Rusong
R
Meng
D003094:Collagen / Q000378:metabolism; D004549:Elastin / Q000378:metabolism; D005109:Extracellular Matrix / Q000378:metabolism*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D020782:Matrix Metalloproteinases / Q000378:metabolism* / Q000528:radiation effects; D016133:Polymerase Chain Reaction / Q000379:methods; D012867:Skin / Q000378:metabolism* / Q000528:radiation effects*; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000378:metabolism* / Q000528:radiation effects; D014467:Ultraviolet Therapy
D019715:Tissue Inhibitor of Metalloproteinase-1; D003094:Collagen; D004549:Elastin; D020782:Matrix Metalloproteinases