The Experimental Study Of Skin Photoaging Treated By1320nmND:YAG Laser

Background and ObjectiveHuman skin photoaging mainly refers to the phenomenon of aging caused by ultraviolet radiation and other environmental factors. It is characterized with rough skin, wrinkle and colored spot. So it doesn’t only affect a person’s appearance, but also has a positive correlation with skin cancer. Its mechanism of pathogenesis is not very clear now. For treatment of skin photoaging there are many ways. YAG laser treatment developing as a wrinkle firming surgery in recent years has less trauma and faster clinical healing. It has obtained a good therapeutic effect in clinic. But its therapeutic mechanism is not clear. In this study, the mechanism of the skin photoaging and YAG laser treatment are discussed further with rat model of skin photoaging. And the clinical therapeutic effect for skin photoaging will be expected.Methods40male SD rats were selected for this study. Among them,10rats were selected randomly as control group. The other30rats were replicated as model of skin photoaging. Then these30rats were divided randomly into three groups (photoaging group, laser treatment group, naturally recovering group). HE staining was done with each treated rat skin to detect its pathology. Then RNA was extracted and transcribed into cDNA by reverse transcription. After that, SYBR Green I real time PCR was done to detect the mRNA expression level of of (β-actin, collagen Ⅰ, collagenⅢ, CTGF and TGF-β1.ResultsVisual observation:The rat back skin of photoaging group appeared thickened, rough and there were deep wrinkles. After the YAG laser treatment the symptoms of photoaging alleviated. But that of laser control group did not change obviously. Microscopic observation:The HE staining of photoaging group, epidermis looked like disordered, loosen, thickened and uneven. The dermal collagen fiber broke off and arranged out of order. Even the aggregation can be seen. There was infiltration of inflammatory cells in epidermis. After the YAG laser treatment, the symptoms of photoaging were improved obviously. Real time PCR results:Compared with the control group, the mRNA expression of collagen Ⅰ, collagen Ⅲ, CTGF and TGF-β1declined obviously in photoaging group. After the YAG laser treatment, the mRNA expression increased obviously. Compared with the laser control group, except CTGF, the mRNA expression of collagen Ⅰ, collagen Ⅲ and TGF-β1was raised obviously.Conclusions1320nm ND:YAG laser treatment has a significant effect for the skin photoaging of rats. The mechanism may be related to its ability that can increase the mRNA expression of collagen Ⅰ, collagen Ⅲ and TGF-(31in laser treatment group.