RESUMEN
ObjectiveTo predict the active ingredients and mechanism of action of lavender in protecting skin photodamage based on network pharmacology and molecular docking technology，and further verify possible signal pathways via animal experiments. MethodThe active ingredients and potential targets of lavender were obtained by SwissTargetPrediction，PharmMapper， and literature. Skin photodamage-related targets were searched from GeneCards，Online Mendelian Inheritance in Man （OMIM），DrugBank and DisGeNET databases. After common targets of the two were screened out，STRING was adopted to analyze the protein-protein interaction （PPI） network，where topological analysis and core target screening were performed by CytoNCA plug-in of Cytoscape 3.8.2. Based on DAVID， gene ontology （GO） annotations and Kyoto Encyclopedia of Genes and Genomes （KEGG） pathway enrichment analysis were carried out among the intersection targets， and the active ingredients of lavender and the signal pathway proteins were selected and verified via molecular docking with AutoDock vina 1.1.2. Finally， mouse photodamage model was established by UVB irradiating the bare skin of mouse back， and the skin condition was observed by naked eyes. Hematoxylin-eosin （HE） and picric acid-acid fuchsin staining （Van Gieson， VG） were used to observe the pathological changes of mouse skin tissues. Western blot was employed to detect the protein expression in mouse skin tissues to further validate the key signal pathways. ResultIn this study，6 active ingredients of lavender，526 potential targets，2 688 disease-related targets，and 258 intersection targets were screened out， and 16 core targets were obtained by PPI network. Additionally， 113 related signal pathways were obtained by KEGG pathway analysis，among which phosphatidylinositol 3-kinase/protein kinase B （PI3K/Akt） pathway and nuclear transcription factor-κB （NF-κB） signal pathway might play a key role in skin photodamage protection by lavender. Molecular docking showed that the active ingredients and the signal pathway proteins were well docked. Animal experiments indicated that the total flavonoids of lavender improved the appearance and histopathological condition of mouse skin， reduced the relative expression levels of phosphorylated（p）-PI3K，p-Akt，and B cell lymphoma 2 （Bcl-2） proteins （P<0.05，P<0.01）， and increased relative expression level of Bcl-2-associated X protein（Bax） （P<0.05）. ConclusionLavender exerts synergistic effect in resisting skin photodamage，with the characteristics of multi-components，multi-targets，and multi-pathways， which provides a basis for subsequent in-depth research on the complex mechanism of lavender against skin photodamage.
RESUMEN
To establish a simple and reliable animal model of skin photo-damage, 20 mice were treated with 8-MOP and exposed to UVA (UVA 320-400 nm) for 24 h. After irradiation, the structure of the epidermis and dermis, collagen fibers, elastic fibers were observed by using HE staining and Weigert technique and compared with the normal controls. The acanthosis and epidemis proliferation with accompanying hyperkeratosis and parakeratosis were observed. Inflammatory infiltration was noted in the dermis. The elastic fibers became coarse, irregularly arranged and clustered, with their number increased. The collagen fibers showed obvious degeneration and some amorphous materials could also be observed. The blood vessels were irregularly dilated and vascular walls were thickened, with infiltration of inflammatory cells. It is concluded that murine photodamage model can be quickly, conveniently and reliably established by means of 8-MOP/UVA.