The Study On The Effect Of TGF-β/Smad Signal Transduction Pathway To The MRNA Expression Of MMP-1 And Pro-collagen Ⅰ In The Process Of Photoaging Of Artificial Skin By Solar Ultraviolet

Objectives:1. to construct the photoaging model of artificial skin by culturing and constructing artificial skin in vitro.2. to study the effect of MMP-1, pro-collagenⅠ, TGF-βtypeⅠand TGF-βtypeⅡreceptors mRNA expression of artificial skin photoaging by solar ultraviolet.3. to investigate the effect of TGF-β/Smad Signal Transduction Pathway in the process of skin photoaging.Methods:1. The compound artificial skin including epidermis and dermis was prepared by culturing 3D organ cultivation model.2. The activity of fibroblast cells, which were irradiated by UV(wavelength of 280-400nm,0J/cm2-40J/cm2), were tested by MTT assay, to choose a proper UV dose.3. The changes of mRNA expression quantity of MMP-1, pro-collagenⅠ, TGF-βtypeⅠand TGF-βtypeⅡreceptors were tested by means of Real-Time RT-PCR (SYBR GreenⅠDNA-binding dye).Results:PartⅠ:The compound artificial skin including epidermis and dermis was constructed successfully. Fibroblast cells, which distribute in reticular collagen fibers, and layered keratinocyte were reticulate observed by HE staining.PartⅡ:Comparing with blank group, the viability of cells in artificial skin, which was irradiated by 10J/cm2 UV or 20J/cm2 UV, were not inhibited obviously. However, when the dose of UV was up to or more than 30 J/cm2, the viability of cells in the treatment group decreases obviously in dose-dependent manner.PartⅢ:1.After the artificial skin was irradiated by 30 J/cm2 UV, the amount of mRNA of MMP-1 increased obviously (P＜0.05); after added with TGF-β1, it decreased significantly (P＜0.01). Being added with TGF-β1 8 hours after irradiation of 30 J/cm2 UV, it was higher than the control (P＜0.05). 2. After being exposed by 30 J/cm2 UV, the mRNA expression quantity of pro-collagenⅠin artificial skin reduced obviously (P＜0.05). After added with TGF-β1, it increased significantly (P＜0.01). Being added with TGF-β1 8 hours after the UV radiation, it was lower than the control group(P＜0.05).3. The difference of the amount of mRNA expression of TGFβRⅠamong different groups was not obviously(P＞0.05).4. After being exposed by 30 J/cm2 UV, the quantity of mRNA of TGF-βRⅡwas down-regulated significantly (P＜0.01). After added with TGF-β1, it reduced significantly (P＜0.01). Being added with TGF-β1 8 hours after exposure of 30 J/cm2 UV, it was lower than the control (P＜0.01).Conclusion:1. The artificial skin with epidermis and dermis was constructed successfully.2. The photoaging model of compound artificial skin was constructed for the first time.3. It is proved that UV could suppress TGF-β/Smad signal transduction pathway by inhibiting the expression of TGF-βRⅡmRNA. While decreaseing the expression of pro-collagenⅠmRNA in dermis, UV could increase the expression MMP-1 mRNA. With these effects, UV made collagen synthesis decreased and its degradation increased, which resulted in photoaging of artificial skin.4. It is proved that TGF-βRI didn't play an important role in the process of artificial skin photoaging by UV.