Primary Study On Intervention And Mechanism Of Salidroside In Mice Skin Senescence Induced By Atmospheric Fine Particles

BackgroundIn recent years,with the aggravation of air pollution and the increase of people’s attention to skin health,researches on the relationship between atmospheric fine particles(also,PM2.5)and skin are increasing.In vitro,PM2.5 can directly damage the skin cells.Several clinical studies have confirmed that PM2.5 can synthetically induce skin senescence through skin exposure,respiratory tract,digestive tract and so on.According to our observation,construction workers,who exposed to air pollutants frequently,often don’t take basic protective measures such as wearing respirators during construction.It is well known to all that long-term and chronic respiratory tract intake of PM2.5 can cause respiratory diseases.Then,can PM2.5 intake through respiratory tract cause skin aging?PM2.5(especially its water-soluble components)can induce the formation of reactive oxygen species(ROS)in cells.ROS induced by ultraviolet inhibits receptor type protein-tyrosine phosphatase-kappa(RPTP-κ)and transactives epidermal growth factor receptor(EGFR)and then activates the Erk-AP-1-MMP-1 pathway,leading to degradation of collagen and elastin and skin senescence.Among them,AP-1 can also increase the expression of EGFR.High expression of EGFR in skin tissue is an early event during skin senescence process,occuring before the obvious pathological changes and involving in the process of skin senescence.Previously,our team found that PM2.5 could promote EGFR expression.Then how about the the result of this experiment?Salidroside is the main active ingredient of Rhodiola rosea.Salidroside has strong antioxidative activity.It is known as "natural antioxidant" and has the effect of scavenging reactive oxygen species.Then will it inhibit the expression of EGFR and interfere with the process of skin senescence induced by PM2.5?Objectives(1)To explore whether intratracheal-instillation of PM2.5 can affect EGFR expression and induce skin senescence in mice,and to verify the reliability of our previous results;(2)to explore whether salidroside can interfere with the above processes;(3)to supplement PM2.5 skin toxicology;(4)to scientificly guide to special populations who exposed to PM2.5 for a long time;(5)to provide theoretical basis for the development of salidroside products for anti-skin-senescence.Methods(1)PM2.5 were collected by a sampler nearby a construction field in Baiyun District,Guangzhou,in December,2017;(2)The obtained products were made into PM2.5 dry powder.40 BALB/c female mices were randomly and equally divided into saline blank control group and low/medium/high dose of PM2.5 group.The doses of PM2.5 were 1,4.8 and 24.0mg/kg,respectively.Mices were treated liquid(1.5ml/kg)respectively by intratracheal instillation once per day for 5 consecutive days;(3)40 BALB/c female mices were randomly and equally divided into high dose of PM2.5+saline blank control group and high dose of PM2.5+low/medium/high dose of salidroside group.The doses of salidroside were 10.0,20.0 and 80.0mg/kg,respectively.After treatment of PM2.5 by intratracheal instillation,mices were treated respective liquid(10.0ml/kg)by gavage once per day for 5 consecutive days;(4)observed hair and skin changes before,after and during experiment;(5)At the 24h after finishing the experiment,skin tissues were collected to detect the expression level of EGFR mRNA by real-time fluorescent quantitative PCR;(6)SPSS and RStudio for statistical analysis.Conclusions(1)Respiratory infusion of PM2.5 could induce skin senescence of mices by promoting the expression of EGFR,which was consistent with the results of our previous research,so the reliability of the conclusions were confirmed;(2)salidoside could inhibit skin senescence by inhibiting the expression of EGFR,indicating that it is of great clinical application value to develop salidroside products for anti-skin-senescence.