Protective Effects And Mechanisms Of Complexes Combined Deep-sea Fish Skin Collagen Peptides With Different Marine Oligosaccharides Against Ultraviolet-induced Damage

The 21st century is the age of ocean. Oceans are important natural resources for several peptides and oligosaccharides with potential antioxidant properties. Recently, there is a growing demand from the food, pharmaceutical and the cosmetics industry for the development of efficient antioxidants, especially from marine active extracts. The specific properties of each collagen peptide and marine oligosaccahride offer possibilities to produce complexes that can confer unique structural properties. The protein-polysaccharide complexes have been extensively studied and applied in tissue engineering. However, only few studies are available that relate to the improvement of protection agasint UV radiation of such complexes, in terms of their ROS scavenging capability. ROS are generated by UV radiation, resulting in photoaging, cancer and neurological degeneration. Thus, to satisfied with the possible economic and the treatment of disease, study on peptide-oligosaccharide complexes has both scientific significance and application values. In this study, we combined the different (isolated and purified) marine oligosaccharides with collagen peptides of the deep-sea fish skin, and evaluated their antioxidant activities and photoprotective effects, with the investigation of their protective mechanisms against UV-irradiated skin damage and the regular pattern of their cross-linking. The main ideas of this paper are listed below:1. The peptide-oligosaccharide complexes were prepared by combining the different (isolated and purified) marine oligosaccharides with bioactive tilapia skin collagen peptides. The intermolecular interactions between the peptide and oligosaccharide have been investigated by Fourier transform infrared spectroscopy (FI-IR) and size exclusion chromatography (SE-HPLC). The results demonstrate that the intermolecular chain associations were formed between oligosaccharide chains and peptide molecules driven by the electrostatic, intermolecule hydrogen bond and hydrophobic interactions.2. Chemical and cellular level assays were performed to measure the antioxidant activity and protection against UV radiation of some peptide-oligosaccharide complexes vis-a-vis the activity of its original or native molecules. Results indicated that the antioxidant activities and protective effects against UV radiation of all the complexes were stronger than that of their individual native peptides, especially for MA1000+CP and k-ca3000+CP.3. Analysis of the protective mechanisms of peptide-oligosaccharide complexes was performed by FCM, ELISA, western blot and confocal. Results indicated that the complex targeted mitochondria after penetration of cell membrane, and suppressed intracellular ROS production as well as increased the antioxidant enzymes activities. The antioxidant properties of the complex can attenuate UV-induced skinphoto-damage by modulating MMP-1 and collagen I expression, as well as suppressing cell apoptosis through the MAPKs signaling pathways.4. The surface electrical properties and the microscopic structures of the peptide-oligosaccharide complex and its independent original molecules were performed by using zeta potential analyzer and Atomic force microscopy. Results indicated that the close combinations of oligosaccharide chains and peptide molecules mainly driven by the electrostatic interactions.In conclusion, the surface electrical properties and the degree of polymerization (DP) of oligosaccharides have an influence to the different degree on the conformation of peptide-oligosaccharide complexes and protective effects against UV radiation. The present findings open up new avenues into the drug design of highly efficient peptide-oligosaccharide complexes and provide strong technical support for the high added value utilization of marine aquaculture industry.