长脉宽与Q开关1064nm Nd:YAG激光对皮肤作用的比较

Comparison of histologic,biochemical and mechanical properties of murine skin treated with the long-pulse and Q-switched 1 064-nm Nd:YAG lasers

目的:比较长脉宽1064nm Nd:YAG激光和Q开关1064nm Nd:YAG激光照射对小鼠皮肤的影响。方法:分别使用长脉宽1064nm Nd:YAG激光(脉宽为3ms、50ms)和Q开关1064nmNd:YAG激光(脉宽5ns)对小鼠背部脱毛后的皮肤进行照射,共照射4次,每次间隔1周。检测照射后不同时间点的皮肤弹性、皮肤羟脯氨酸含量,真皮内胶原增生情况以及红斑指数和经表皮失水量的变化情况。结果:从首次照射后第3或4周至第7周,各实验组的皮肤弹性都明显好于对照组;首次照射7周后各组实验侧的皮肤羟脯氨酸含量和真皮内胶原厚度都较对照组显著增大(P<0.01),但各实验组之间无显著差异;苦味酸-天狼猩红染色-偏振光法检查显示各组增生的胶原主要为Ⅰ型胶原。首次激光照射后即刻,各实验组的经表皮失水量及Q开关1064nm Nd:YAG激光实验组的红斑指数都较其对照组显著增高(P<0.01),并于1周内恢复。结论:长脉宽1064nm Nd:YAG激光可以取得与Q开关1064nm Nd:YAG激光对皮肤相似的效果,且不良反应较轻。

Objective： To compare the effects of the long-pulse 1 064-nm Nd：YAG and the Q-switched 1 064-nm Nd：YAG laser non-ablative treatments on mouse skin in vivo. Methods： KM mice were used for the study. Every mouse back was denuded and in the each mouse three treatment areas and three control areas were prepared on the opposite side of the spine. The long-pulse 1 064-nm Nd：YAG laser （pulse duration： 3 ms and 50 ms） and Q-switched 1 064-nm Nd-YAG （pulse duration： 5 ns） were applied to murine dorsal skin for four times at an interval of one week. Then biophysical parameter measurements were carried out with a multi probe adapter, and skin samples were taken for hydroxyproline content assay, histological study and estimation of collagen type Ⅰ and Ⅲ. Results： All laser treatments improved the skin elasticity of KM mice significantly from 3 or 4 weeks after the first treatment to the end of the experiment. After the 7-week follow-up, the hydroxyproline of the skin of 3ms, 50ms and 5ns groups showed 16.17%, 23.50% and 18.73% increase respectively compared to their controls （P〈0.01）. The enhancement of the dermal thickness was 27.29%, 24.70% and 25.20% respectively, which significant higher than the controls （P〈 0.01）. However, no statistical significance was found between them. Picrosirius-polarization method revealed type I collagen increased strikingly in three laser groups after laser treatments. Erythema values showed significant increases （321±144） comparing to their controls （206±75） immediately after the Q-switched Nd：YAG laser treatment （P〈0.01）, and the damage recovered in 7 days. The values of trans-epidermal water loss （TEWL） for all treated areas differed significantly from their controls and increased immediately after laser irradiation, then recovered in 7 days after treatment. Condusions： The long-pulse 1064-nm Nd：YAG is identical to the Q-switched 1064-nm Nd：YAG laser in improving the skin elasticity, skin hydroxyproline and dermal thickness. Both of them have mild side-effect.