Experimental Study Of The Treatment Of Rat Skin Photoaging By2940nm Er:YAG Combined With Catechin

Objective:To explore the effect of the2940nm Er: YAG laser and catechins on photoagingskin, then further to investigate the synergistic effect of the two methods.Methods:According to the different treatment, we classfy60KM mice into5groups:A(The control group)，B(photoaging group)，C（photoaging+laser group），D（photoaging+catechin group），E（photoaging+laser+catechin group）.There are12mice in each group. After putting the intervention group exposured in UV for8weeks, and using laser and catechins to intervent. HE staining, Immunohistochem-istry and Western blot were employed to detect the skin structure in mice、theactivities of superoxide dismutase(SOD)、the contents of malondial dehyde(MDA）、Ⅰtype collagen and MMP-1protein expression.Results:The skin of group B (photoaging group) turned to be grossly dry and rough.wecan see apparent skin grooves and apparent pigmentation on the skin. HE stainingshowed that the thickness of the epidermis is not even and there are shed skinoccasional in cuticle hyperplasia. In the dermis,collagen become thinner andthinner,and the fibrous layer is broken, with the thicker collagen fibers. At the sametime,we can see the hyperplasia in horny layer. When compared to other groups,Theactivity of SOD become weaker and weaker(＊P﹤0.01),while the MDA increasesignificantly(＊P﹤0.01).Immunohistochemistry showed that in the dermis,collagenbecome thinner and thinner,and the fibrous layer is broken, with the thicker collagenfiber,average optical density results of skin collagen fibers was markedly dropped(＊P﹤0.01); MMP-1expression was Significantly increased(＊P﹤0.01).Compared with group B(photoaging group),the skin of the intervention groupsare improved obviously. It is clearly to see that skin is much smoother, ruddier andmore exquisite with wrinkles disappear totally. There is no obvious pigmentation inthe naked eyes. We can see the integrated structure of the epidermis and shed skin occasional in cuticle hyperplasia from HE staining. In the dermis, new collagenbecome thicker, and glands slightly increased, which is in according with thehypothesis. The SOD activity increased significantly (＊P﹤0.01;◆P﹤0.05). Whilethe MDA decreased obviously (＊P﹤0.01). Immunohistochemistry showed that newcollagen was increased, the thickness of dermis was significantly increased;averageoptical density results of skin collagen fibers was markedly increased(＊P﹤0.01);MMP-1expression was Significantly reduced(＊P﹤0.01).Compared E with A、D group,we can get the Statistical results of MMP-1(◆P﹤0.05；＊P﹤0.01). Compared E with C group,we can get the Statistical results ofSOD and MDA(＊P﹤0.01).Conclusion:both2940nm Er: YAG laser and catechins could make the skin tightness andyouthful, stimulated collagen regeneration, reduced MDA contents、SOD activity、theexpression of MMP-1, etc. The effect of collaborative treatment of them were moresignificant when compared with the pure using of laser or catechins.which is worthyof further research and provide the reliable support to the future clinical applications.