The Effect Of Salicylic Acid On Skin Barrier Function In Mice

Background and objective:Atopic dermatitis(AD) is a recurrent inflammatory skin disease,the patient with AD often have skin itching、dryness、scaling.Complex etiology of AD pathogenesis is not entirely clear in recent years that the skin barrier function defects have a great relationship with the pathogenesis of AD.Related proteins involved in the process of epidermal differentiation:Filaggrin,Loricrin,Involucrin,these proteins involved in the formation of a stable cornified envelope,i.e CE,which can promote the differentiation of the epidermis,also the main barrier to resist the physical stimulus of external environment.Kallikrein-related peptidase expressed in the granular layer and the stratum corneum cell gap,such as tissue kallikrein7(KLK7) has a role of clearage angle desmosomes and bridge YI SU-1,it is possible to adjust the stratum corneum shedding.These proteins have an important role to maintain the barrier function of the skin.The CE plays an important role not only in the normal external barrier function of the skin but also in the formation of the cornified epithelium.Previous studies have shown that the destruction of the barrier will immediately stimulate the synthesis of lipids and DNA resulting in epidermal hyperplasia.In this study,the role of salicylic acid in mouse epidermal damaged,by measuring the changes of mouse epidermal TEWL and the expression of epidermal differentiation protein INV,LOR,FLG and KLK7,and to explore the role of salicylic acid on epidermal barrier function.To provide experimental evidence for clinical salicylic acid treatment of atopic dermatitis.Methods:C57BL/6J mice were divided into4groups(1%、3%salicylic acid group、matrix group and blank group) using the tape paste method C57/6J mice skin barrier disruption model.Topical drug(blank group without any drug),respectively,we measure the transepidermal water loss(TEWL) before pasting,0h、2h、4h、6h、12h、24h、48h、72h after pasting with Tewameter TM210.And skin lesions in mice tissue was taken at different time points by immunohistochemistry and Real-Time PCR was used to detect the expression of the four kinds of proteins:INV,LOR,FLG,KLK7.The results of TEWL using one-way anova results with the situation as mean±tandard deviation,all P values are two-sides test results,P<0.05was considered statistically significant.Results:l.The effect of salicylic acid in mice TEWL:The group that usage of3%salicylic acid topical cream TEWL decline fastest,the TEWL of blank group decline slowest,1%salicylic acid topical creams and matrix TEWL rate of decline is relatively close,and between the usage of3%salicylic acid cream and blank group. The difference of TEWL between3%salicylic acid cream group and the control group was statistically significant in4h、6h、12h、24h、48h(P<0.05or P<0.01),and in6h、2h、24h the difference was significant.2.The percentage of barrier recovery:the percentage of barrier recovery that was usage of1%salicylic acid cream group respectively are27.50%,44.80%.59.47%、173.47%、85.15%、90.71%、95.41%after2h、4h、6h、12h、24h、48h and72h of the skin barrier damaged.The percentage of barrier recovery that was usage of3%salicylic acid cream group respectively are35%、62.34%、83.48%、90.84%、96.80%、96.67%、96.70%.the percentage of barrier recovery that was usage of matrix group respectively are30.17%、47.88%、62.82%、73.11%、82.10%、87.51%、94.05%。the percentage of barrier recovery that was usage of the control group respectively are20.99%、37.74%、48.08%、58.71%、74.62%、83.60%、93.63%。the percentage of barrier recovery of3%salicylic acid cream group is greater than the other group in2h、4h、6h、12h、24h、48h, the difference was statistically significant (P<0.05) The percentage of barrier recovery of1%salicylic acid cream group is greater than the blank group in4h、6h、12h、24h, the difference was statistically significant (P <0.05). The percentage of barrier recovery of matrix group group is greater than the blank group in4h、6h、12h、24h, the difference was statistically significant (P <0.05).The percentage of barrier recovery of the matrix group and the1%salicylic acid cream group is relatively close,and was not significantly different,the difference was not statistically significant(P>0.05).3. Real-Time PCR was used to detect salicylic acid on the expression of INV、LOR、FLG and KLK7:the expression of INVmRNA、LORmRNA、FLGmRNA are topical3% salicylic acid cream group was higher than1%salicylic acid cream group、matrix group and blank group in6h,12h,24h, the differences were statistically significant (P<0.05), the3%salicylic acid cream group mRNA expression is the most obvious in12h. The expression of INVmRNA、LORmRNA、FLGmRNA are topical1%salicylic acid cream group was higher than matrix group and blank group in6h,12h,24h, the differences were statistically significant (P<0.05).the expression of mRNA is similar between matrix group and the blank group, and the differences were not statistically significant (P>0.05). The expression of klk7mRNA are topical3%salicylic acid cream group was lower than1%salicylic acid cream group, matrix group and blank group in6h,12h and24h, the differences were statistically significant (P<0.05). The3%salicylic acid cream group mRNA expression is the lest obvious in12h. The expression of klk7is topical1%salicylic acid cream group was lower than matrix group and blank group in6h,12h and24h, the differences was statistically significant (P<0.05). The expression of klk7mRNA is similar between matrix group and the blank group, and the differences were not statistically significant (P>0.05).4. Immunohistochenistry was used to detect salicylic acid on the expression of INV、 LOR、FLG:the expression of INV、LOR、FLG are3%salicylic acid cream group is higher than matrix group and blank group in12h, the differences were statistically significant (P<0.05), the expression of INV、LOR、FLG is similar between matrix group and the blank group, and the differences were not statistically significant (P>0.05). The expression of klk7are3%salicylic acid cream group is lower than matrix group and blank group in12h, the differences were statistically significant (P<0.05), the expression of klk7is similar between matrix group and the blank group, and the differences were not statistically significant (P>0.05).Conclusions:1.A low concentration of salicylic acid cream and matrix can reduce the TEWL of the barrier damaged skin by measuring the TEWL.Salicylic acid cream to reduce TEWL was stronger than the matrix,the strongest effect is the salicylic acid cream with a concentration3%,which reduced the TEWL best.2. The low concentration of salicylic acid cream with the promotion of the expression of INVmRNA、LORmRNA and FLGmRNA and the protein,also it can increase the content of protein in INV、LOR and FLG of stratum corneum,meantime it can be to suppress the expression of the protein and KLK7mRNA,and reduce the content of klk7in stratum corneum.Thus possible to increase the stratum corneum water cooperation with the cuticle repair faster,thus speeding up the speed of recovery of damaged skin barrier.In which the3%salicylic acid cream has the most significant effect,the best results.This provides a theoretical basis for the treatment of disease which has skin barrier breakdown with a low concentration in clinic.