Study On The Correlation Between Skin Barrier Damage And Photoaging

Objective:By establishing an animal model of skin barrier damage and photoaging,observe the changes of the skin barrier during photoaging,and explore the impact of skin barrier damage on photoaging.Methods:1、To construct a mouse skin barrier damage and photoaging model,Balb/c mice were randomly divided into four groups:control group,tape group,light group,tape+light group,5 mice in each group.The control group was a blank control,only hair removal was performed,no other treatment was done;tape group:after hair removal,"3M tape" was used to repeatedly and evenly stick the mice’s back skin 3-5 times to increase the TEWL value by 3 times;light group:the MED value was measured,and then the light dose and light time were calculated according to the reference literature.SUV1000 daylight simulator was used to simulate daylight irradiation three times a week.Duct tape+photoluminescence group:After shaving and taping the mice’s back skin,the TEWL value was increased by 3 times and then photoluminescence was performed at an interval of 10 min(the dose was the same as that of the photoluminescence group).Mice were treated every Monday,Wednesday and Friday for three months.After the end of modeling,the skin of the mice’s back was photographed by high-definition photography to observe the aging state of the mice’s skin appearance and to make a preliminary rating of the skin appearance.Later,orbital blood and skin tissues of mice were taken for backup testing.2、The collected blood was separated from the serum,and the changes of ROS,SOD,CAT,GSH-Px and HYP in the blood of four groups of mice were detected by ELISA.The results were statistically analyzed.3、The skin tissues were taken from the mice after execution and the following tests were performed:①Paraffin-embedded sections were performed to observe the histopathological changes in the skin of the four groups of mice;②RT-qPCR was used to detect the inflammatory factors IL-1α,IL-1β,IL-6,TNF-α,matrix metalloproteinases MMP-1 and MMP-9,type I and type III collagen,and TGF-β2 and Smad2 mRNA expressions.The results were statistically analyzed.Results:1、mice skin appearance state:control group mice back skin is flesh-colored,smooth and elastic,no damage to the barrier;tape group destroyed the skin barrier,visible with slight exudation,capillary dilation of the barrier damage performance.In the lighted group,there were obvious wrinkles,dry and flaky epidermis,but the epidermal damage was shallow.The barrier destruction and aging of the skin in the duct tape+photoluminescence group was more significant,with a large amount of erythema,wrinkles and desquamation,and rough epidermis.2、TEWL value:There was no change in the TEWL value of the normal group,while the TEWL values of the tape group,the photoluminescence group and the tape+photoluminescence group gradually increased.After three months,the TEWL values of the tape group and the photoluminescence group were significantly higher than those of the normal control group(P<0.05),indicating that long-term UV radiation could also damage the skin barrier,and the difference was more obvious in the tape+photoluminescence group(P<0.05),and the skin barrier was more severely damaged when photoluminescence was performed on the basis of tape application.3、Skin histopathology:in the normal control group,the collagen fibers were of uniform thickness,relatively neatly arranged,and the elastic fibers were evenly distributed;in the tape group,slight inflammatory cell infiltration was seen;in the light group,compared with the normal group,the epidermis became thicker,the collagen fibers became thinner,disorganized and broken,and the elastic fibers increased,thickened and distorted;in the tape+light group,after UV irradiation of the skin barrier damage,the collagen fibers and elastic The destruction of collagen fibers and elastic fibers in the tape+photoluminescence group was aggravated to varying degrees compared with the photoluminescence group alone.4、RT-qPCR:The mean number of IL-1α,IL-1β,IL-6,TNF-α,MMP-1,MMP-9 mRNA in the tape group was higher than that in the control group(P<0.05),the mean number of Smad2 mRNA was lower than that in the control group(P<0.05),and the differences of CollagenⅠ,CollagenⅢ,TGF-β2 mRNA were not statistically The differences in CollagenI,CollagenⅢ and TGF-β2 mRNAs were not statistically significant.The number of IL-1α,IL-1β,IL-6,TNF-α,MMP-1 and MMP-9 were higher in the light group than in the control group(P<0.05),and the number of CollagenⅠ and Smad2 mRNA were lower than in the control group(P<0.05),and the differences of CollagenⅢ and TGF-β2 mRNA were not statistically significant.The mean numbers of IL-1α,IL-6,TNF-α,MMP-1,MMP-9 mRNA were higher in the tape+light group than in the light group alone(P<0.05),and the mean numbers of CollagenⅠ and TGF-β2 mRNA were lower than in the light group(P<0.05),while the differences of IL-1β,CollagenⅢ and Smad2 mRNA were not statistically significant.It is suggested that the disruption of the skin barrier by trans-tape can increase the expression of IL-1α,IL-1β,IL-6,TNF-α,MMP-1,MMP-9 genes and decrease the expression of Smad2 in tissues;after UV radiation,the expression of IL-1α,IL-1 β,IL-6,TNF-α,MMP-1,MMP-9 genes in tissues was similarly increased,and the expression of type I collagen,Smad2 Smad2 was reduced;while IL-1α,IL-6,TNF-α,MMP-1,MMP-9 gene expression in the aging tissues further increased and type I collagen and TGF-β2 decreased compared with the light-irradiated group alone on the basis of skin barrier disruption by the tape.5、ELISA:The mean number of ROS in both the tape group and the photoluminescence group was higher than that in the control group(P<0.05),and the mean numbers of HYP,SOD,CAT and GSH-Px in both groups were lower than those in the blank control group(P<0.05).The mean number of ROS in the duct tape+illumination group was higher than that in the illumination group(P<0.05),while the mean numbers of HYP,SOD,CAT,and GSH-Px were lower than that in the illumination group(P<0.05).It is suggested that tape disruption of skin barrier,as well as UV radiation can increase the expression of ROS in tissues,while decreasing the expression of HYP,SOD,CAT,and GSH-Px in tissues.UV irradiation on top of skin barrier disruption increased ROS expression in tissues,while HYP,SOD,CAT,and GSH-Px expression could be further reduced.Conclusion:1、Damaged skin barrier can cause skin to age to some extent.2、Ultraviolet radiation can damage the skin barrier and produce inflammatory reaction.It also causes collagen reduction and disorganized arrangement,imbalance of skin antioxidant system,and eventually photoaging.3、Damage of skin barrier by UV radiation after tape can aggravate photoaging in mice..