The Protection Effect Of Intense Pulsed Light On The Fibroblasts Injury Induced By UVA I Radiation

The injury of normal human skin induced by ultraviolet radiation (ultraviolet radiation, UV), including sunburn,immunosuppression, photoaging and skin cancer, one of which, photoaging, is a hot topics in the field of skin research. In recent years, the clinical efficacy of a new technology project, Photorejuvenation technology revealed that intense pulsed light (intense pulsed light, IPL) could eliminate wrinkles, accelerate tissue repair and so on. Our project try to explore the effects of IPL on human skin fibroblasts (fibroblast, FB), including growth activity, cell proliferation and cell cycle changes, explore the possible mechanism, and provide theoretical basis for wrinkles rejuvenation with IPL.First of all, we isolated and cultured primary human skin fibroblasts from healthy young foreskin after circumcision, gave UVAI irradiation simulating light damage. Cell Counting Kit-8 (CCK-8) assay, flow cytometry (FCM) analysis and western blot were used to observe the changes of skin fibroblasts after being irradiated by IPL, including cell growth activity, cell proliferation and cell cycle protein expression. Results:(1) The cell proliferation activity slowed down 48h after irradiation with 9J/cm2 doses of UVA I. Subsequently, proliferation activity was significantly reduced at every time points compared with the control group, P<0.05. The cell proliferation activity of FB was significantly increased after the first 72h irradiated by IPL compared with the control group, P<0.01. The proliferative activity of FB treated by IPL after UVA I, was significantly better than the single UVA I treatment group, P <0.05.(2) After 48h irradiated by single UVA I or IPL, G1 phase cells of FB cells decreased, while the S phase cells increased. The S phase cells increased with IPL treatment after UVA I irradiation compared with single UVA I group, and G1 phase cells were less than single UVA I group, p <0.05.(3) After 48h irradiated by single UVA I, cell cycle-related proteins CyclinD1 and CDK2 decreased. After UVA I+IPL irradiation, CyclinD1 and CDK2 were lower than the normal control group, but were significantly higher than those of single UVA I treatment, p <0.05.Our results revealed that IPL could promote fibroblast proliferation and DNA synthesis with CCK-8, FCM and western blot technology,which could explain the photorejuvenation phenomenon of IPL observed in clinical and provided a theoretical basis for IPL rejuvenation...