| Objective:(1) To compare the pharmacodynamic study between the intranasal administration(I.N) and intravenous administration(I.V) of TAT-ha FGF14-154;(2) To investigate the ameliorative effect and preliminary mechanism of TAT-ha FGF14-154 via intranasal administration in the APP/PS1 and SAMP8 mouse model of Alzheimer’s disease, providing the pharmacological basis of TAT-haFGF14-154 in treatment of AD.Methods:(1) The level of ha FGF entering mice cortex, hippocampus and olfactory bulb via intranasal administration of TAT-ha FGF14-154 were determined by using Enzyme-linked immunosorbent assay(ELISA). Using behavioral test and ACh detection to compare the pharmacodynamic study between the intranasal administration(I.N) and intravenous administration(I.V) of TAT-ha FGF14-154.(2) After five weeks of intranasal administration of TAT-ha FGF14-154(35, 100, 300μg/kg) on APP/PS1 and SAMP8 mice, the learning and memory abilities were inspected by Morris water maze test and the step-down test; ELISA method was carried out to measure the function of the cholinergic system of mice brains. Aβ1-42 and 4G8 deposits were detected using immunohistochemistry; then the Nissl and Luxol Fast Blue staining were conducted to investigate the Nissl body and myelin sheath of neurons in mice brains. Finally, the Western-blot method was carried out to detect the PI3K-AKT-CREB/GSK3 pathway, synapse-associated protein and APP processing in mice brains.Results:(1) At the same dosage(300μg/kg), TAT-ha FGF14-154 had a significant advantage in terms of entering the brains compared with ha FGF14-154 via both intranasal administration(I.N) and intravenous administration(I.V).(2) After five weeks of intranasal administration of TAT-ha FGF14-154 on APP/PS1 and SAMP8 mice, the learning and memory abilities of mice from TAT-ha FGF14-154 treatment group were significantly improved in the behavioral test and the function of the cholinergic system was also ameliorated; TAT-ha FGF14-154 activates the PI3K-AKT-CREB pathway to upregulate the synapse-associated protein(Synaptophysin, GAP43, PSD95), as well asactivating the PI3K-AKT-GSK3 pathway to reduce the Aβ1-42 and 4G8 deposits by upregulating ADAM10, IDE, NEP and downregulating BACE.Conclusion:(1) Intranasal administration of TAT-ha FGF14-154 exerts more significant therapeutic effects compared with intravenous administration; combination use of TAT and the intranasal administration well solved the bottleneck problem of macromolecule protein in treatment of the central nervous system diseases.(2) Nasal delivery of TAT-haFGF14-154 improves memory impairments and protects against neurodegeneration in the APP/PS1 and SAMP8 mouse model of Alzheimer’s disease.(3) The mechanism is probably related to the regulation of cholinergic system and the PI3K-AKT-CREB/GSK3 pathway. |
