Abstract: Objective To look for a small molecular neurotrophin which could promote production and/or differentiation of neural stem cells (NSCs). Methods 1.Embryo hippocampal NSCs were cultured in vitro. 2. The neurospheres were identified by antibodies of bromodeoxyuridine (BrdU), glial fibrillary acid protein (GFAP), microtubule associated protein 2 (MAP2) and Galactocerebroside (GalC). 3. The cells were divided into four groups, which were control group, FBS treated group, transsequence of APP 5-mer peptide treated group, APP 5-mer peptide treated group. The morphology of NSCs was observed in above four groups. 4. Cell counts, detection of clone information rate and diameter of clone were done to study the effect of APP 5-mer peptide on production of NSCs. 5. In addition, we also detected the MTT metablism rates in all groups. Results 1 The NSCs formed neurospheres and grew in floating. They were BrdU-positive. GFAP-positive, MAP2-positive and GalC-positive cells appeared after FBS were added into the medium. 2. The morphology of NSCs was not changed in APP 5-mer peptide treated group and trans-sequence group compared with the control group. 3. The cell number increased in APP 5-mer peptide treated group as compared with the control group. There were no apparent differences between the control group and the transsequence treated group. 4. The clone formation rate and diameters of neurospheres increased in APP 5-mer peptide treated group. 5. The MTT metabolism rate increased in APP 5-mer peptide treated group. Conclusion APP 5-mer peptide could promote the production of embryo hippocamal NSCs EM>in vitro/EM>. APP 5-mer peptid

Key words: APP 5-mer peptide, Hippocampal, NSCs, Production, Differentiation, Primary cell culture, Rat