Research on the Improvement Effects of Collagen Peptides and Tremella fuciformis Polysaccharides on the Skin Texture of Aging Mice and Its Mechanism

Objective: To compare the improvement effects of collagen peptides and Tremella fuciformis polysaccharides (TFP) on aging skin texture and explore the underlying mechanism of the action. Method: Aging mice models were established by intraperitoneal injection of D-galactose at a dosage of 120 mg/kg, which were randomly divided into three groups: Model (given saline), collagen (given collagen peptides 830 mg/kg·BW), and TFP (given TFP 100 mg/kg·BW). Adult mice were set as normal group (Normal). The experiments lasted for 8 weeks. All mice were killed at the end of the experiment. The contents of hydroxyproline and hyaluronic acid in the skin, the activities of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and concentrations of malondialdehyde (MDA) in several tissues, the levels of inflammatory cytokines in serum, and the concentrations of intestinal short chain fatty acids (SCFAs) were measured. Results: Collagen peptides and TFP significantly increased the contents of hydroxyproline and hyaluronic acid in aging skin in mice (P<0.01), and the improving effects of TFP were better than that of collagen peptides. Further, both of collagen peptides and TFP significantly improved the activities of GSH-Px and SOD, and reduced the concentrations of MDA (P<0.01) in serum, liver, and heart, but there was no difference between Collagen group and TFP group. Interestingly, TFP showed a better inhibitory effect on the concentrations of IL-1β and TNF-α in serum compared with collagen peptide (P<0.01), though both of them exhibited anti-inflammation activity in aging mice. In addition, the detections of SCFAs in the intestine showed that collagen peptides had no obvious effect on the total SCFAs but increased the concentrations of acetic acid and propionic acid in the colon of aging mice, whereas TFP reversed the alterations in the concentrations of SCFAs in the colon induced by the treatment of D-galactose. Conclusion: Collagen peptides and TFP might improve the aging skin texture by increasing antioxidant activities and anti-inflammatory effects in ageing mice.