Study On The Mechanism Of Two Tilapia Skin Peptides Inhibiting Photoaging-induced By UVB In HaCaT Cells

As the population continues to increase,the ecological environment is destroyed,resulting in an ever-increasing amount of carbon dioxide released from the environment.Eventually,global warming and ozone holes are formed.The medium-wavelength ultraviolet UVB(UltravioletB)in ultraviolet rays is an ultraviolet ray that mainly causes skin damage,which can cause photoaging of the skin and cause skin damage.Therefore,protecting the skin from UVB aging of the skin has become a hot spot of current research.In this study,two tilapia skin peptides TGAGT and LSGTGP were used as materials to study the mechanism of UVB-induced photodamage of HaCaT keratinocytes.HaCaT cells were irradiated with different doses of UVB,and the cell death model was established by thiazole blue colorimetric assay(MTT),which resulted in a cell lethal dose of 30mJ/cm~2.It was confirmed by MTT method that the two tilapia skin peptides TGAGT and LSGTGP were not cytotoxic in the concentration range of 10-100μM,and it was confirmed that the concentration range had an effect on cell viability after UVB irradiation;The two tilapia skin peptides were treated with HaCaT cells for 4 h and then irradiated with UVB for 24h.The results of DNA oxidative damage assay showed that the two tilapia skin peptides had protective effects on oxidative damage of DNA after UVB irradiation.The results of DCFH-DA assay showed that the two tilapia skin polypeptides inhibited the production of reactive oxygen species(ROS)in UVB radiation.The results of Western blotting(WB)showed that the two tilapia peptides could increase Glu.And the expression of SOD content,maintaining the level of intracellular antioxidants;Two tilapia skin peptides protect HaCaT cells after UVB irradiation.The WB results indicate that the expression levels of p38,JNK and ERK proteins in the MAPK signaling pathway of HaCaT cells are increased after UVB irradiation.After protection of the non-fish skin polypeptide TGAGT,the phosphorylated p38 and JNK protein expression levels decreased.However,there is no inhibitory effect on phosphorylation of ERK.As the concentration of tilapia skin peptide LSGTGP increases,the phosphorylated p38,JNK and ERK proteins gradually decrease;The WB experiment further demonstrated that the expression of phosphorylated p65and IκB proteins was reduced after UVB irradiation after protection of both peptides.The results of cellular immunofluorescence assay showed that the two tilapia skin peptides TGAGT and LSGTGP protected HaCaT cells gradually decreased in the cell as the peptide concentration increased.The non-fish skin polypeptide can inhibit the entry of p65 into the nucleus of HaCaT cells by UVB and inhibit the expression of p65;ELISA experiments confirmed that the two peptides can reduce the secretion of MMP-1 and MMP-9 in HaCaT cells after UVB irradiation,and reduce the overexpression of MMP-1 and MMP-9,so that they can not excessively degrade collagen,so collagen played a protective role.At the same time,the two tilapia fish skin polypeptides can also increase the content of type I collagen and improve the self-repairing ability of type I collagen.Therefore,the two tilapia skin peptides TGAGT and LSGTGP can alleviate skin damage caused by UVB radiation and protect skin photoaging caused by UVB;Therefore,two tilapia peptides can inhibit oxidative stress produced by ROS,and mediate MAPK and NF-κB signaling pathways,thereby controlling MMPs in cells and increasing collagen content in cells,with UVB inhibition.Induction of photoaging of HaCaT keratinocytes...