RESUMO
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 in vitro. APP 5-mer peptide doesn't promote the differentiation of embryo hippocamal NSCs in vitro.
RESUMO
Objective To investigate the effects of analog 165 of APP5-mer peptide on the expression of synaptic related proteins in neurons of the hippocampus through intracerebroventricular(ICV) injection of streptozotocin(STZ) in rats. Methods A total of 45 Wistar rats were randomly divided into control group,model group and treated group.Rats in the model and treated groups received intracerebroventricular injection of STZ bilaterally.After three weeks,rats in the treated group received gastric perfusion of analog 165 of APP5-mer peptide.After the four-week treatment,the memory of the rats was surveyed by Morris water maze test.The expressions of synaptic related proteins,such as postsynaptic density95 protein(PSD-95),synaptophysin and ?-Synuclein,were tested with immunohistochemical staining and Western blotting.The ultra-structure of the neurons of hippocampus was observed with transmission electron microscope. Results 1.Full-course swimming time was obviously longer in the model group than that those in the treated and control groups.2.In the model group,the expressions of PSD-95 and synaptophysin decreased,and the expression of ?-Synuclein increased.The treated group normalized the expression of the targeted proteins.3.Retrograde degeneration of the neurons of hippocampus was observed in the model group,and dysmorphic synapses were observed in the neuropil.Conclusion There are low PSD-95,synaptophysin levels and high ?-Synuclein levels in the ICV injected brain of STZ rats.Analog 165 of APP5-mer peptide improves the expression of the three proteins to some extent;therefore it may protect synapse and improve learning ability and memory.