Abstract: The present work aims at adducing further proof of the neurotrophic effect of β amyloid(Aβ)precursor protein(APP)319～335(APP17 mer peptide), through studying the effect of APP17 mer peptide on the neurotoxicity of Aβ, and thereby providing scientific evidence for the pathogenesis of AD and its treatment. APP17 mer peptide and Aβ_25-35 were synthesized by solid phase method and purified by HPLC. Human neuroblastoma cells SY5Y were segregated into 3 groups: normal control group, Aβ_25-35(10μmol/L)damaged group, and Aβ_25-35(10μmol/L)+APP17 mer peptide(10μmol/L)for neuroprotection group. Cell count, MTT metabolic rate, LDH leakage rate, axonal length, area of cell body, NT 3 immunohistorychemical staining and concentration of cytosolic calcium(Ca²⁺)were used as indicators. Compared with normal control group, Aβ_25-35 damaged group showed reduced cell count and MTT metabolic rate, increased LDH leakage rate, diminished axonal length and area of cell body, reduced NT 3 expression, increased concentration of cytosolic calcium(Ca²⁺), but the addition of APP17 mer peptide normalized the foregoing changes. APP17 mer peptide is neurotrophic. It can diminished neurotoxicity of Aβ.

Key words: APP17 mer peptide, Aβ_25-35, neurotrophic