| Aging is one of the most prevalent biological laws of nature. It is a gradual process, with each person’s life. Aging occurs at the cellular level,also, aging reflects the procedures and environmental damage caused by the gene. Aging skin has special significance as a part of the whole aging process. Usually.skin aging is divided into natural aging and photoaging, aging is a natural process of programmed endogenous, formed by the passage of time. And exogenous aging is the accumulation of damage by exogenous causes and other environmental factors generated by contacting or lifestyle, the latter is mainly induced by the sun’s ultraviolet radiation,that is why we call it photoaging.In recent years, with the rapid development of our industrial and agricultural production, air pollution control is lagging behind in the speed of development,it caused the serious air pollution,the word "Haze" gradually into the ordinary people’s vision and topics, Especially in Beijing, Tianjin and Hebei Province, haze is becoming a common weather phenomena, And the main component of haze is the study of this experiment-Fine particulate matter(PM2.5)Effects of PM2.5 are all aspects to the human body, as the body’s largest organ-skin, directly affected by the effects of PM2.5.Though we don’t know how the human body be affected by PM2.5, however, studies show that, PM2.5 plays an important role in human body’s respiratory system, cardiovascular system etc. This study was to investigate the role of PM2.5 in the skin aging process.Skin aging is a complex and lengthy process, many reasons can lead to the gradual accumulation of skin aging, effect of endogenous factors is the major, gradually with the passage of time, manifested in fine and shallow wrinkles, dry skin,relaxation and rough. Skin is most important window exchanges and contact with the outside world of the body,skin aging causes anxiety, depression, low self-esteem and a series of psychological and social problems, serious impact on people’s lives, work.So, prevent and delay skin aging has become one of the hotspots of today’s medical research.Epidermal growth factor receptor(EGFR) is one of the body important autocrine/paracrine growth factor Human EGFR regulatory cell proliferation, differentiation, migrate,etc. Human EGFR plays an important role in In cell development, wound healing and organogenesis. EGFR is an early event in the process of skin aging, it’s a key role in the process of skin aging. Relations between PM2.5 and skin aging is one of the hot study in environmental epidemiology. In this experiment,we study the impact of the mouse’s EGFR mRNA expression on PM2.5, and then explore its possible impact mechanism.Here are several ways that PM2.5 can affect human skin, as follows:1. Direct concentration through the skin pores, absorbing;2. Through the human digestive system;3. Through the human respiratory system;4. Skin trauma, blood system.Comprehensive comparison, in this study, mice received continuous and large doses of intratracheal instillation process, accelerate the slow process of mice’s skin aging,make the experiment more maneuverability and controllability.After intratracheal instillation,we detect the expression of mice’s EGFR mRNA, Indirect judge the effect of PM2.5 in the process of mice’s skin aging.40 female BALB/c mice were randomly divided into 4 groups including 1 saline control group and 3 PM2.5 exposure groups(1.6,8.0 and 40.0mg/kg body weight, respectively).Each exposure group received intratracheal instillation once per day for 3 consecutive days.At the 24h after the last administration,skin tissue and were collected to detect the expression of EGFR mRNA by real-time fluorescent quantitative PCR.The experimental results show, between high-dose group and saline control group,middle-dose group and saline control group, high-dose group and low-dose group, P values less than 0.001, there is a high positive correlation with each other.This study found that, with increasing concentrations of PM2.5, The expression of mice’s EGFR mRNA will be increased.The results also show:there is no significant differences between low-dose group and saline control group,but mice from high-dose group and middle-dose group,their skin aging,and it is dose-related. This may be because the skin tissue have some defenses in a certain concentration of PM2.5, once over the certain concentration, skin tissue defenses are destroyed,caused the high expression of EGFR mRNA.For a further inference, blocking EGFR, is very possible to eliminate or reduce skin aging caused by PM2.5. |
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