Protective Effects Of Soybean Oligopeptide On UVB-induced Photodamage In Human Skin

Background and objectiveWhen the skin tolerated overdose ultraviolet(especially UVB)after irradiation,the protein and nucleic acid in the cells absorb a large amount of ultraviolet light to produce a series of complex abiochemical reactions,resulting in necrosis of epidermal cells and the release of various active medium,which causes vasodilation and edema.The body can against UV induced skin damage by a variety of proteetive measures,such as apoptosis and inflammation.Apoptosis is a processes to remove unwanted cells,including injury and mutation of cells,which is the basic physiological mechanism to maintain homeostasis.P53 is an important apoptosis regulating factor,which plays an important role in the growth and development of cell differentiation.P53 can regulate cell growth,tumor surveillance cells and induce apoptosis.P53 was mainly located in the cytoplasm,which can get into the nucleus after phosphorylation as a transcription factor.P53 can regulate the expression of a series of downstream target genes.If the DNA can not be repaired,p53 can induce activation of Bax and reduced expression of Bcl-2,and then induced unrepaired cells to apoptosis.We can get soybean oligopeptides when soy protein hydrolyzed by hydrolytic enzyme.Soybean oligopeptideschain contains 3-6 amino acids.The molecular weight of soybean oligopeptide less than 1000 kDa,mainly ranges from 300 to 700kDa.In recent years,a variety of biological functions in soybean oligopeptides had been found,such as lowering blood pressure,reducingblood fat content and resisting oxidation.Previous study had confirmed the soybean oligopeptides could effectively relieve photodamage of mice induced by UVB irradiation in our group.We made further research to discuss whether topical SOP can against UVB induced acute photodamage and try to find possible mechanism.MethodsA.In vivo:Topical SOP on acute photodamage of human skin induced by UVB1.Selection of volunteersNine men aged from 23 to 26 years with Fitzpatrick skin type ?-? were recruited.All were in good health with no evidence of acute or chronic diseases,without known photosensitivity.Volunteers were instructed not to take any other medicines until the study was ended.Written consent was obtained from all participants prior to the study.2.Measurement:of Minimal erythema doseMED of every volunteers were measured.Increasing doses of UVB irradiation were given in eight positions of the left forearm flexor aspect,respectively.The minimal dose of UVB lead to erythema as the MED.3.UVB irradiationThe right forearm skin were irradiated with 1.5 MED,SOP creams or matrix were smeared after UVB irradiation five minutes.4.Detection of relevant indicatorsErythema index,Melanin index,skin hydration and transepidermal water loss were detected by MPA9.B.In vitro:Topical SOP on acute photodamage of foreskin in vitro inducced by UVB1.Groups20 cases of fresh human foreskin tissue were randomly divided into four groups:control group,UVB group,UVB ?matrix group,UVB + SOP group.Five foreskin tissue in each group,each foreskin was divided into 4 parts to cultivate,corresponding to 8hs 24h,48h and 72h four time points.2.UVB irradiation180mJ/cmZof UVB was given to UVB group,UVB ?matrix group and UVB+SOP group.Tissue will be organized into incubator after SOP was smeared.3.Collection of tissue and detection of relevant indicatorsWe collected tissues of four time points,and used HE staining to detect sunburn cells,TUNEL staining to detect apoptotic cells,iununohistochemistry to detect photoproducts CPDs,p53,Bax and Bcl-2.ResultsA.In vivo:Topical SOP on acute photodamage of human skin induced by UVB1.Effects of topical SOP on El induced by UVBThe El of UVB irradiated groups were significantly higher than the control group(P<0.05).The El of the UVB+high concentrations of SOP group and the UVB?moderate concentrations of SOP group were lower than that of UVB irradiated group in 1 day,3 days and 10 days.2.Effects of topical SOP on MI induced by UVBThe Ml of UVB irradiated group in 3 days and 10 days of irradiation were significantly higher than the control group(P<0.05).There was no significant difference among the MI of UVB?various concentrations of SOP groups and UVB irradiation group after 1 day,3 days and 10 days(P>0.05).3.Effects of topical SOP on skin hydration induced by UVBThe skin hydration of UVB irradiated groups in 1 day,3 days were lower than the control group(P<0.05).There was no significant difference among UVB?various concentrations of SOP groups and UVB irradiation group at three time points(P>0.05).4.Effects of topical SOP on TEWL induced by UVBThere was no significant difference among all the groups at each time point(P>0.05).B.In vitro:Topical SOP on acute photodamage of foreskin in vitro induced by UVB1.Effects of topical SOP on CPDs induced by UVB CPDs positive cells were not found in control group within the epidermis.In contrast,a large number of CPDs positive cells were detected in UVB group.CPDs positive cells of UVB + SOP group were significantly less than the UVB group(P<0.05).2.Effects of topical SOP on sunburn cells and apoptotic cellsinduced by UVBA large number of sunburn cells appeared in the epidermis after UVB irradiated,cand up to a maximum number in 24h after irradiation.Statistical analysis showed that the number of sunburn cells in UVB?SOP group were significantly less than UVB group at 8h,24h,48h and 72h after UVB irradiation(p<0.05).The same as apoptotic cells.3.Effects of topical SOP on apoptosis-relatedprotein:p53,Bax,Bcl-2induced by UVBControl group within weak expression of p53 protein in epidermis in each time point,the expression of p53 protein was increased at all time points and up to the highest expression to 24h in UVB group,the same as apoptotic cells.Bcl-2 expression of groups irradiated by UVB were significantly decreased compared with the control group(P<0.05).The expression of Bcl-2 in UVB+SOP group is higher than UVB group at 48h and 72h(P<0.05).ConclusionsOur study found that topical SOP reduce El,accelerate the clearances and apoptotic cells induced by UVB.SOP has protective effect on the photodamage induced by UVB,may through inhibiting the reduction of Bcl-2 and increase of p53,Bax.Our study found that topical SOP canagainst the erythema reaction induced by UVB irradiation,can accelerate the removal of CPDs and reduce apoptotic cells.The SOP has aprotective eflfecton UVB-induced acute photodamage in human skin.