Abstract: Objective To investigate the expression of TGF-β1 after intense pulsed light(IPL) management to rat skins and elucidate the possible treatment mechanism of IPL.Methods Fifteen Sprague Dawley(SD) rats were included in the study,and the dorsal skins of subjects were irradiated by intense pulsed light with cut-off wavelength filter of 560 nm, fluence of 27 J/cm~2,pulse duration of 3 ms and a double pulse duration of 10 ms.Skin biopsy from each subject from both treated and untreated(control) sites were performed on postoperative 4 weeks.The specimens were processed by immunohistochemistry(IHC) and analyzed quantitatively with microscopic photographs using imaging analysis software system.In addition,immunohistochemical staining was also employed to study the distribution of TGF-β1 in normal rat skin and the specific TGF-β1 changes after intense pulsed light irradiation.Results With skin immuno-staining detecting weakly positive expression to TGF-β1,TGF-β1 was diffusely present in the whole layers of normal rat skin,including the epidermis and ECM in dermis.Furthermore,TGF-β1 was significantly increased with intense pulsed light irradiation after 4 weeks.The more intensive brown-staining in the epithelium around the adnexal follicle and ECM in the dermis were found, which were significantly different from those of control skin sites(P<0.001).A number of fibroblasts were easily found in TGF-β1 rich areas.Conclusion Intense pulsed light irradiation can markedly regulate the secretion of TGF-β1 in rat skin which may be the presumable mechanisms of intense pulsed light treatment to photoaged skin.

Key words: Intense pulsed light, Photoaged skin, Transforming growth factor-β1(TGF-β1)