Effects of intense pulsed light irradiation on the content of collagen fibers, elastic fibers and hyaluronic acid in Kunming mouse skin.

Objective To investigate the effects of intense pulsed light (IPL) irradiation on the content of collagen fibers, elastic fibers and hyaluronic acid in Kunming mouse skin. Methods The dorsal skin of mice was divided into two areas: the right area was irradiated with IPL, and the left remaining unirradiated served as the control. Skin specimens were taken from the back of mice on day 1, 3, week 1, 2, 4 and 8 after the irradiation and subjected to staining with HE, sirius red and Gomori aldehyde-fuchsin for examinations of histological changes, type Ⅰ and Ⅲ collagen fibers and elastic fibers. The hydroxyproline and hyaluronic acid content in skin tissues of mice was determined with ultraviolet spectrophotometry and radioimmunoassay respectively. Results After irradiation, a significant increase was observed in dermal thickness on week 2 (t =4.623, P＜ 0.05), 4, and 8 (t = 3.904, P＜ 0.05), in type Ⅲ collagen fiber (t = 5.129, P＜ 0.05) on week 1,in type Ⅰ and Ⅲ collagen fibers on week 2, 4 and 8 (both P＜ 0.05), in elastic fibers from week 2 to 8 (P ＜0.05), and in hydroxyproline content from week 1 to 8 (all P ＜ 0.05) in the skin of mice compared with unirradiated mice. In detail, dermal thickness increased by 18.71% on week 4, and type Ⅲ collagen fiber by 40.54% in irradiated mice compared with unirradiated mice. Further more, the hyaluronic acid content was elevated from day 1 to 3, but gradually declined from week 1 to 8, and remained statistically higher from day 1 to week 8 (P ＜ 0.05) in irradiated mice compared to unirradiated mice. Conclusion IPL irradiation could induce an increase in the content of collagen fiber, elastic fiber and hyaluronic acid in the dorsal skin of mice. Key words: Intense pulsed light;  Collagen;  Elastic tissue;  Hyaluronic acid;  Mice