Effects of Royal Jelly Peptide on Motor Ability and Gene Expression in Zebrafish Model of Alzheimer's Disease

Objective: Investigation of the trait improvement impact of royal jelly enzymatic products (royal jelly peptides) on Alzheimer's disease (AD) model zebrafishes. Methods: 150 wild-type AB strain zebrafishes (4 days after fertilization, 4 dpf) were randomly divided into normal group, model control group, donepezil hydrochloride positive control group (3.33 μg/mL), royal jelly enzymatic digest lyophilized powder-1 group (LPR-1, 1000 μg/mL) and royal jelly enzymatic digest lyophilized powder-2 group (LPR-2, 1000 μg/mL), and these groups were added in 6-well plates, respectively. The volume of each well was 3 mL, and 30 tails of zebrafishes were employed in each group. Except for the normal group, zebrafishes in other groups were treated with aluminum chloride hexahydrate (180 μmol/L) to establish AD models. The efficacy of recovery of motor dysfunction, improvement of responsiveness, inhibition of acetylcholinesterase (AchE) and inhibition of apoptosis were evaluated for each experimental group after treated with corresponding drugs simultaneously for 24 h. The relative expressions of TNF-α, caspase-3 and BDNF genes were also calculated and their effects on related genes were analyzed. Results: Compared to the model control group, the LPR-1 and LPR-2 administration groups zebrafishes showed prolonged total locomotor distance (highly significant, P<0.01), the differential speed of light and dark motion per minute (P<0.001) and the relative expression of BDNF gene (P<0.001) were significantly increased. Acetylcholinesterase (AchE) fluorescence values (extremely significant, P<0.001) and brain apoptotic cell fluorescence intensity (highly significant, P<0.01) were decreased, and the relative expression of TNF-α gene (highly significant, P<0.01) and caspase-3 gene (significant, P<0.05) were also decreased. Conclusion: Both of LPR-1 and LPR-2 have anti-Alzheimer's disease efficacy, and have potential for the development of functional foods for the prevention or treatment of Alzheimer's disease.