Research on Anti-aging Function and Mechanism of Pond Turtle Protein-derived Peptides on Drosophila melanogaster

Objective: To explore the anti-aging function and mechanism of pond turtle protein-derived peptides (PTPDP) on Drosophila melanogaster. Methods: PTPDP were obtained by enzymatic hydrolysis of turtle meat. Nutrients content, molecular weight distribution and amino acid composition of PTPDP were determined. D. melanogaster were fed with 0.2%, 0.4%, and 0.8% PTPDP. The activities of superoxide dismutase (SOD) and catalase (CAT), along with the content of malondialdehyde (MDA) were determined to analyze the anti-aging function of PTPDP. The anti-aging mechanism was explored by measuring the expression of antioxidant genes (Sod1, Sod2 and Cat) and lifespan-related genes (mth and Rpn11) in female D. melanogaster fed with 0.8% PTPDP. Results: The enzymatic hydrolysis products of turtle meat were mainly composed of small molecule peptides less than 1000 Da. PTPDP were rich in amino acids with antioxidant activity, such as glycine, glutamic acid and proline. In the survival experiment, the average lifespans of female and male D. melanogaster were significantly prolonged by 18.92% and 9.37% (P<0.01), respectively. In the antioxidant activity experiment, the SOD activity of female and male D. melanogaster increased significantly by 7.13% and 7.37% (P<0.05); the CAT activity of female and male D. melanogaster increased significantly by 42.14% and 84.66% (P<0.01); the MDA content of female and male D. melanogaster decreased significantly by 22.22% and 23.08% (P<0.05). In female D. melanogaster fed with 0.8% PTPDP, the expression of anti-oxidant related genes Sod1, Sod2 (P<0.05) and Cat (P<0.01) were significantly up-regulated, and genes (mth and Rpn11) related to lifespan also showed different degrees of regulation (P<0.01). Conclusion: PTPDP increase the antioxidant activity of D. melanogaster by affecting the expression of antioxidant genes and lifespan-related genes, thereby prolonging the lifespan of D. melanogaster. This mechanism implies that PTPDP has potential anti-aging effects.