| Objectives①To study the process of skin aging and potential compounds against skin aging.②To study the mechanism of action for skin aging with intense pulsed light.Methods①With D-galactos combined with UVA and UVB irradiation on the dorsal skin of mice, a model was established resembling to human skin aging. Then the morphologic alteration of dorsal skins was observed under microscope, and analyzed by computer systems. The biochemical indicator and the change of p53,PCNA,TGF-β1 were monitored.②The model group were treat by the IPL system in vivo under certain wavelengths with different energy densities, continuously irradiated two times, interval two weeks. Then the morphologic alteration of dorsal skin was observed under microscope, and analyzed by computer systems. The biochemical indicator and the change of the gene proteins p53,PCNA,TGF-β1 were monitored.Results①Visual inspection: significant aging-charactersitic in the mice of model group appeared;②Evaluation of biological markers :there was a statistical significance in the light absorption value of SOD, MDA, HYP among the normal group, the D-galactos group, the UV group and the model group (P<0.05); after the IPL treatment, there were changes happened on the light absorption of SOD, MDA, Hyp had a statistical significance(P<0.05);③Observing the morphology of pathological slices:Normal group: The epidermis was very thin and have few cell layer, even be monolayer, the arrangement of collagen fiber in dermis was sparse and scattered, which was tenuity and pink;The D-galactos group: The epidermis and the dermis were thin, accompanying with reducing cell layer, loose collage fiber, and elastic fiber to reduce the total area.The UV group: The epidermis was thickened, accompanying with hyperkeratinization, mature collage fibre decrease in the number of new collage fibre.The model group: The epidermis was thickened, accompanying with hyperkeratinization. The cell layer increase, Thinning the thickness of the dermis, collagen fibers decrease in thickening of aging, with loose, elastic fiber thickening, with irregular, decrease in the number.IPL-treated groups: Compared with normal group, model group, control group mice treated with the IPL thicker skin, more cell layers, thinning the thickness of the dermis, collagen fibers decrease in thickening of aging, with loose, elastic fiber thickening, with more irregular decrease in the number; with the model group compared to the control group, IPL skin treatment group of mice a little thin, dermal thickening, shallow dermal fibroblasts markedly increased markedly increased collagen fibers, was with the level of densification; elastic fibers with the rules , the number increased slightly④Immunohistochemical staining:①The expression of p53: the difference among the normal group, the D-galactos group, the UV group and the model group was notable, and it had a statistical significance (P<0.05); there was no statistical difference(P>0.05) between the IPL treated 1w group and the post-modeling 1w group ; there was no statistical significance between the post-modeling 3w group and the IPL treated 3w group(P<0.05);②The expression of PCNA: the difference among the normal group, the D-galactos group, the UV group and the model group was notable and it had a statistical significance (P<0.05); there was no statistical difference (P>0.05) between the IPL treated 1w group and the post-modeling 1w group; and there was a statistical significance between the post-modeling 3w group and the IPL treated 1w group (P<0.05);③The expression of TGF-β1: the difference among the normal group, the D-galactos group, the UV group and the model group was notable and it had a statistical significance(P<0.05); there was no statistical difference (P>0.05) between the IPL treated 1w group and the post-modeling 1w group; And there was a statistical significance between the post-modeling 3w group and the IPL treated 1w group(P<0.05);Conclusion①D-galactose combined with UV can cause skin aging remarkably and rapidly. It is an ideal model to study skin aging.②The genes protein p53,PCNA,TGF-β1 may play an important role in the process of the skin aging.③IPL is an effective method for D-galactose and UV group ,the mechanism of which may improve the balance between oxidation and anti-oxygen, recover oxydasic active, improve the cell multiplication and tissue damage. |
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