Protective effect of intense pulsed light on fibroblast injury induced by UVA I

Abstract

Objective To study the protective effects of intense pulse light (IPL) on the injury of normal human skin fibroblasts (FB) induced by ultraviolet A (UVA Ⅰ ) in vitro and to explore its possible mechanism. Methods The human skin fibroblasts were isolated and cultured, and then irradiated by UVA Ⅰ (9 J/cm2) and IPL (15 J/cm2), respectively. The proliferative ability of the cells were detected by CCK-8. Cell cycle was detected by flow cytometry, and cylin D1 and CDK2 protein expression levels were detected by Western blot. Results Different doses of UVA Ⅰ irradiation caused certain damages of cultured fibroblasts. With the increasing of of UVA Ⅰ dose, cell proliferation was decreased. Cells went to death at the exposure to 11 J/cm2 UVA Ⅰ , while the proliferative activity did not change much at 7 J/cm2 UVA Ⅰ . Cells were treated with UVA Ⅰ for other 2 days, then with IPL irradiation for other 2days, showing clear stimulating to the cell proliferation as compared with the cells that received UVA Ⅰ treatment only. Flow cytometry results showed that an increase of cell proliferating index, and cell cycle protein cyclin D1 and CDK2 expression levels were also upregulated after IPL irradiation.Conclusion UVA Ⅰ irradiation may cause cell damage as showed by cell growth index, cyclin D1 and CDK2 expression, and this injury could be protected partly by IPL treatment. The intense pulsed light may regulate the expression of cyclin proteins that may promote normal fibroblast proliferation, which could be one of the mechanisms of IPL skin rejuvenation. Key words: Intense pulsed light (IPL); Proliferation; Cell cycle; Cosmesis