| UV irradiation is one of the main exogenous factors that cause skin aging,manifested as water loss,reduced elasticity,redness and sunburn,that is,skin photoaging.With the improvement of consumers’ aesthetic awareness and the increasing demand for multi-functional and natural skin care products,collagen peptides and natural antioxidants have become important research objects for scholars and the main raw materials for skin care products.As the main component of skin care products,the dosage of collagen peptides directly affects the skin care effect and economic cost.In addition,there are a wide variety of natural antioxidants,and most of the current studies stay on the evaluation of a single component and the in vitro evaluation of multiple components,and lack in vivo horizontal comparison.Therefore,this project reasonably screened out the dose of Tilapia collagen peptides and the type and combination of natural antioxidants,and compounded them to verify the effect of the compound in improving skin photoaging and preliminary explore its action pathway,in order to provide theoretical basis and formulation for the development of skin care products.(1)A comparative study on the effect of different doses of collagen peptides against skin photoaging: In this chapter,a long-term UVA+UVB irradiation-induced skin photoaging model was established using BALB/c Nude mice.Low(600 mg/kg),medium(1200 mg/kg)and high(1800 mg/kg)doses of collagen peptide were given intragastric administration.By measuring endogenous components of skin,collagen synthesis and degradation,inflammatory factors,and tissue sections,the improvement effect of different doses of collagen peptide on skin photoaging was comprehensively evaluated.The results showed that ingestion of collagen peptides could activate the expression of TGF-β/Smad pathway-related factors related to collagen synthesis,significantly promote the synthesis of hyaluronic acid(HA),hydroxyproline(Hyp),type I and III collagen,down-regulate the expression of matrix metalloproteinases(MMPs)-1,3,12,up-regulate the expression of tissue inhibitors of metalloproteinases(TIMPs)-1,2,decrease the content of interleukin-1α(IL-1α)、interleukin-1β(IL-1β)、interleukin-6(IL-6)、tumor necrosis factor-α(TNF-α)(P<0.05),and improve the morphology of skin tissue.These results suggest that collagen peptide intake may promote endogenous collagen synthesis by activating TGF-β/Smad pathway,and reduce collagen degradation,relieve inflammation,and ultimately improve skin photoaging.Among them,medium dose and high dose have better effects.Considering the experimental results medium dose and economic cost,medium dose collagen peptide is optimized for subsequent compounding.(2)A comparative study on the effect of different natural antioxidants against skin oxidative damage: A short-term irradiation-induced skin damage model was established in this chapter.By measuring redox homeostasis,collagen degradation,inflammatory factors and skin phenotype indicators,the improvement effect of pomegranate extract,Haematococcus pluvialis extract,acerola cherry extract and acerola cherry extract+vitamin E on skin oxidative damage was compared and evaluated.The results showed that intake of natural antioxidants could promote the expression of redox-related Nrf2/ARE signaling pathway-related factors,significantly reduce the contents of reactive oxygen species(ROS),malondialdehyde(MDA)and protein carbonyl(PC),increase the expressions of glutathione peroxidase(GSH-Px)and catalase(CAT),down-regulate the expressions of MMP-1,9,12,and reduce the content of IL-6,TNF-α content,decrease the value of a*(P<0.05).The above results indicate that natural antioxidants may balance the body’s redox homeostasis by activating the Nrf2/ARE signaling pathway,thereby inhibiting collagen degradation,relieving inflammation,improving skin phenotype,and delaying skin photoaging.Among them,Haematococcus pluvialis extract and acerola cherry extract+vitamin E have better effects,and are preferably used for subsequent compounding.(3)Validation study on the effect of collagen peptides and natural antioxidant complexes against skin photoaging: Based on the results of the previous two batches of animal experiments,a long-term irradiation-induced skin photoaging model was established to evaluate the combination of collagen peptide and natural antioxidant in this chapter.By measuring the skin endogenous components,collagen synthesis and degradation,redox homeostasis,inflammatory factors,skin phenotypic indicators,and tissue sections,the effect of the compound in improving skin photoaging was verified and its mode of action was preliminarily explored.The results showed that the compound could activate the expression of TGF-β/Smad pathway-related factors,significantly promote the synthesis of HA,Hyp,and type I collagen.And it also could activate the expression of Nrf2/ARE pathway related factors,significantly reduce the content of ROS and MDA,increase the expression of GSH-Px and CAT,reduce the secretion of IL-1α,down-regulate the expression of MMP-9,up-regulates the expression of TIMP-1,reduces the skin value of a*,increase the content of water,and improve the structure and morphology of skin tissue.The above results indicate that the complexes may promote collagen synthesis by activating the TGF-β/Smad pathway,and may inhibit collagen degradation by activating the Nrf2/ARE signaling pathway to balance redox homeostasis,improve skin inflammation,and improve skin tissue morphology and phenotype.Among them,compound 3(collagen peptide+Haematococcus pluvialis extract+acerola cherry extract+vitamin E)works better.In summary,this subject compares the anti-photoaging effects of low,medium and high doses of collagen peptides on skin,combined with the economic cost,concluded that medium doses of collagen peptides were superior.Then comparing the effects of pomegranate extract,Haematococcus pluvialis extract,acerola cherry extract and acerola cherry extract+vitamin E against skin oxidative damage,it was concluded that Haematococcus pluvialis extract and acerola cherry extract+vitamin E were superior.Finally,the optimal dose of collagen peptides and natural antioxidants were compounded,and it was concluded that medium dose collagen peptides+Haematococcus pluvialis extract+acerola cherry extract+vitamin E had better effects,and tentatively explored the pathway of anti-photoaging effect of the compound on skin might be related to its complementary effect. |
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