Shrimp peptide QMDDQ improves scopolamine-induced memory impairments by activating the Notch1 signaling pathway

QMDDQ is peptide derived from shrimp that ameliorates scopolamine-induced memory impairment. In this study, behavioral experiments in mice showed that QMDDQ could reduce the latency, number of working memory errors of the total distance moved, number of reference memory errors, number of traversals of the original platform, and escape latency in mice. QMDDQ decreased AChE vitality and increased ACh, DA, and 5-HT content. HE staining revealed that the cells in the hippocampal areas exhibited a tight tissue structure, neat arrangement, clear outline, and no cell necrosis in the QMDDQ group. Immunohistochemistry showed that, the expression level of Notch1 protein was reduced, and that of the antibody antigen complex was reduced in the QMDDQ group. Immunofluorescence staining showed a decrease in the number of GFAP and Iba-1 of QMDDQ group. TEM revealed that the mitochondrial cristae are intact and clear of QMDDQ group. QMDDQ decreased expression levels of Notch 1, STAT3, HES1, GFAP, and Iba-1 and activated Notch1 signaling via western-blotting. Pharmacokinetic studies have shown that QMDDQ can be stably absorbed into the bloodstream, with absorption occurring within 12 h and metabolism being completed within 24 h. This study establishes a theoretical basis for active peptides to ameliorate memory impairment and initiates the development of memory-enhancing functional foods.