| Background/purpose: The objective was to compare the effects of the long-pulse 1064-nm Nd:YAG and 1064-nm Q-switched Nd:YAG laser non-ablative treatments on mouse skin in vivo.Methods: KM mice were used for the study. Every mice's back were denuded, and got three treatment areas and three control areas on the opposite side of the spine. The long-pulse 1064-nm Nd:YAG laser (pulse duration: 3ms and 50ms) and 1064-nm Q-switched Nd:YAG (pulse duration: 5ns) were applied to three groups respectively for four times at an interval of one week, with 10% overlap. Biophysical parameter measurements were carried out with a Reviscometer immediately, 1,2,3,4,6 and 7 weeks after the first laser treatments. Skin specimens were taken for hydroxyproline content assay, histological study and estimation of collagen type I and III as long as 7 weeks after the first treatment.Results: Erythema values showed significant increases immediately after the Q-switched Nd:YAG laser treatment (320.73 ± 143.70) to their controls (206.13±74.6), and the change recruited after 7 days; but the long-pulse Nd:YAG laser have no obvious changes. The values of trans-epidermal water loss (TEWL) for all treated areas differed significantly from their controls and increased immediately after laser irradiation (P<0.01) , then recovered at 7 days after treatment. All laser treatments improved the skin elasticity of KM mice significantly from three or four weeks after the first treatment (P<0.05) . But there is no statistical difference between each laser groups. The hydroxyproline of the skin in 3ms, 50ms and 5ns pulse duration group showed 16.17% , 23.50% and 18.73%(p< 0. 01) increase respectively compared to... |
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