Effects of intense pulsed light on collagens and PCNA expression in mouse skin

Objective:To observe the effect of intense pulsed light(IPL) on collagens and PCNA expressions in mouse skin and elucidate the biological mechanisms of photorejuvenation.Methods:Mice were irradiated on their right sides of the back with IPL(32 J /cm2),and their left sides were selected as control areas.At day 1,7,14 and 28 after treatment,skin specimens were taken at treated and non-treated areas,respectively.Histological and collagens changes were observed by hematoxylin-eosin-staining and Van Gieson staining.In addition,the expression of PCNA was investigated by immunohistochemistry at day 28 after irradiation.Results:Compared with non-treated regions,dermal thickness of treated regions had no significant change at day 1,7,14 and 28(P 0.05).Collagens staining were stronger in treated regions than in non-treated areas at day 14 and 28(P 0.05).The expression of PCNA also increased at day 14 and 28 after irradiation in treated areas(P 0.05).Conclusion:IPL can enhance the content of collagens and also can increase the expression of PCNA in mouse skin.