非剥脱性激光嫩肤作用机制的实验研究

Experimental study on the mechanism of nonablative skin photorejuvenation

目的 探讨激光非剥脱性嫩肤的作用机制。方法 昆明小鼠分A、B、C三组，分别以1320nm激光照射小鼠背部左侧皮肤1、2和3次，背部右侧作自身对照，共4个疗程。免疫组化法检测碱性成纤维细胞生长因子（bFGF）和转化生长因子β1（TGF—β1）在受照射小鼠皮肤中的表达。体外培养人成纤维细胞，随机分对照组及低、中、高三个照射能量组。用1320nm激光以15J/cm^2、20J/cm^2和24J／cm^2能量照射，于0、24、48和72h ELISA法检测上清液bFGF和TGF—β1的分泌水平。结果 照射后bFGF和TGF-β1在组织中的表达增加，激光照射3次组与各组比较，差异有统计学意义（P〈0．01）；成纤维细胞计数增加（P〈0．05）；bFGF分泌的量，20J／cm^2、24J／cm^2能量组增加，24h达高峰，与对照组相比，差异有统计学意义（P〈0．01）。TGF—β1分泌的量在照射的各能量组均下降，24h达峰底（P〈0．01）。结论 ①激光对成纤维细胞的直接作用是促进bFGF分泌，抑制TGF—β1分泌；而对组织的综合作用是两者分泌均增加；②非剥脱性激光通过光或热的作用直接刺激成纤维细胞分裂增殖；使成纤维细胞自分泌bFGF增加并通过血管因素的作用使bFGF及TGFβ1增加，促进成纤维细胞分裂增殖并使胶原合成增多。

Objective To explore the Mechanism of nonablative skin rejuvenation. Method The Kunming mice be used as subjects and divided into three groups（ A, B, C）. A, B, C groups were irradiated with 1 320 nm coohouch laser（20 J/cm^2 ） in the skin of left back ; B and C groups were irradiated two and three times respectively ; the skin of right back of A, B, C groups was adopted as control. The expression of bFGF and TGF-β1 in the mouse skin was examined by the immunohistochemistry .The fibroblasts were isolated from the foreskin and cultured. One group is a control and other three ones are low, intermediate and high energetic groups respectively. The fibroblasts were irradiated by laser with 15 J/cm^2 ,20 J/cm^2 and 24 J/cm^2 energy for three times. We examined the levels of bFGF and TGF-β1 by ELISA in 0, 24,48 and 72 hours. Results According to this research on immunohistochemistry result, there are significant differences in the expression of bFGF and TGF-β1 between the group irradiated by three times and others（ P 〈 0.01 ）. The number of fibroblasts get increased after being irradiated by laser. The ELISA result indicates that the secretion of bFGF increased in the group of intermediate and high energetic level after laser irradiating and may reach the peak at 24 hours（ P 〈 0.01 ）. The amount of TGF-β1 secretion, however, seems to get decreased in each group at all energetic levels, and at 24 hours it can reach the top level as well. Conclusion The direct influence of laser on the fibroblasts is to promote secretion of bFGF and to inhibit secretion of TGF-β1 , while its influence on the tissue is to promote the secretions of the both. Nonablative skin rejuvenation not only can induce fibroblasts to secrete more bFGF but also induce the blood vessels to release cytokines which stimulate endothelial cell to express more of bFGF and TGF-β1. Furthermore, fibroblastic proliferation can accelerate by laser＇s irradiating.