Wheat germ peptides improving liver aging damage in rats through the AMPK/SIRT1 pathway

Wheat germ, as a byproduct of wheat flour processing, is extremely abundant in resources but has yet to be fully and reasonably utilized. This study focused on the wheat germ active peptide ADWGGPLPH obtained in the early stage using naturally aged SD rats as the animal model of liver aging damage and 9-month-old rats as controls. Wheat germ-derived active peptides were continuously administered by gavage until the age of 21 months. The effect of wheat germ-derived active peptides on liver aging-related damage in naturally aged rats was examined, and its molecular mechanism was preliminarily explored in conjunction with the H₂O₂-induced aging HepG2 cell model. The wheat germ-derived active peptide ADWGGPLPH could increase the activity of antioxidant enzymes such as superoxide dismutase, total antioxidant activity, glutathione peroxidase, and catalase in the rat serum and liver while reducing malondialdehyde levels, improve oxidative stress levels in rat liver, reduce interleukin (IL)-6 and IL-1 levels in the serum and liver and β, matrix metalloproteinase-3, and tumor necrosis factor-alpha levels, and increase the secretion of anti-inflammatory factor IL-10, improving the inflammatory environment in the liver of aging rats. After treatment with wheat germ-derived active peptides, the liver structure was significantly improved, fat vacuoles were reduced, cells were arranged neatly, and alanine aminotransferase and aspartate aminotransferase levels were significantly reduced. Wheat germ-derived active peptides can effectively improve the abnormal structure and growth status of cells in the aging liver, reduce the loss of liver quality during aging, reduce the expression levels of aging marker proteins P53 and P21, alleviate the degree of liver aging damage, and slow down the aging process of the liver. By using inhibitors, activators, siRNA, and others, wheat germ-derived active peptides can regulate aging-related processes by activating the AMPK/Sirt1 signaling pathway. This study is significant for the development of a healthy aging dietary structure and comprehensive utilization of wheat germ resources.