Study On The Effect Of Salmon Skin And Tilapia Skin Collagen Peptides On Regulating Skin Collagen Synthesis And Microbial Colonization To Promote Wound Healin

In this study,the low molecular weight of Salmon salar skin collagen peptides(Ss-SCP)and Tilapia nilotica collagen peptides(Tn-SCP)was prepared using Salmon salar skin and Tilapia nilotica skin as row materials.The basic properties of Ss-SCP and Tn-SCP were analyzed.The effects of Ss-SCP and Tn-SCP on wound healing in rats were evaluated by measuring the wound healing rate,the collagen content,the healing skin quality of wound and other indexes in a back trauma rat model.The impact of Ss-SCP and Tn-SCP on TGF-β/Smad pathway were explored,which is a key pathway regulating collagen synthesis.Moreover,the effects of Ss-SCP and Tn-SCP on the skin microbiota composition were explored.These studies are beneficial to clarify the effect of Ss-SCP and Tn-SCP on the improvement of wound healing that is based on the regulation of collagen synthesis and skin microbiota composition.The main results are as follows:(1)The basic properties analysis of Ss-SCP and Tn-SCPSs-SCP and Tn-SCP were prepared from Salmon Salar skin and Tilapia nilotica skin,and the basic properties were analyzed.It was found that the protein content of Ss-SCP and Tn-SCP were 90.56 g/100 g and 92.90 g/100 g,respectively,and the collagen content was83.22 g/100 g and 86.40 g/100 g,respectively.The amino acid composition results showed that the content of Gly in Ss-SCP and Tn-SCP was 20.11g/100 g and 23.67g/100 g,the characteristic amino acid Pro was 9.51g/100 g and 10.42g/100 g,and the content of Hyp was9.93g/100 g and 8.72g/100 g,which were consistent with the amino acid composition pattern of type I collagen.The molecular weight determination results showed that the molecular weight of Ss-SCP and Tn-SCP was about 500 Da,which was relatively homogeneous and mainly contained 2-5 amino acid oligopeptides.(2)The improvement effect on wound healing of Ss-SCP and Tn-SCP in ratsThe promoting effect on wound healing of Ss-SCP and Tn-SCP was evaluated by established the rat wound model.The results showed that the wound healing rate,the wound healing,the tensile strength and elongation at break of wound healing skin,and the skin quality of wound was significantly promoted by Ss-SCP and Tn-SCP.(3)Ss-SCP and Tn-SCP promoted the collagen synthesis in wound skin based on TGF-β/Smad pathwayIn order to explore the possible mechanism in promoting collagen synthesis of Ss-SCP and Tn-SCP,the collagen content of wound skin and the expression level of the relative regulatory factors in TGF-β/Smad pathway which is the key pathway of collagen synthesis was evaluated.The results showed that the contents of HYP and collagen in wound tissues,the expression levels of VEGF and β-FGF,and the gene and protein expressions of TGF-βand TβRII were significantly promoted by Ss-SCP and Ts-SCP,while the gene and protein expressions of Smad 7 was decreased.These results indicated that Ss-SCP and Tn-SCP promote collagen synthesis in traumatized skin through TGF-β/Smad pathway.(4)Ss-SCP and Tn-SCP improved wound healing by regulating skin microbial colonizationThe association between wound healing and skin microbiota was explored by evaluating the impact in relative regulatory factors in skin tissue and skin microbiota composition of Ss-SCP and Tn-SCP.The results showed that Ss-SCP and Tn-SCP significantly up-regulated the contents of NOD2 and BD14 in wound skin,decreased the contents of pro-inflammatory factors TNF-α,IL-6 and IL-8,increased the secretion of antiinflammatory factor IL-10,decreased the inflammatory response in wound healing process,and promoted wound healing.The result of 16 S rDNA showed that the abundance of harmful bacteria such as Stenotrophomonas,Bradyrhizobium,and Phyllobacterium is high in MC group,while Ss-SCP and Tn-SCP changed the microbiota composition in wound and significantly increased the abundance of beneficial bacteria such as Leuconostoc,Enterococcus,and Bacillus.These results indicated that SS-SCP and Tn-SCP could regulate the colonization of skin microbiota through NOD2 and BD14,improve the inflammatory response of wound,and promote wound repair.