RESUMO
The main pathological hallmark of Alzheimer's disease is the deposition of amyloid-beta (Aß) peptides in the brain. Aß has been widely used to mimic several aspects of Alzheimer's disease. However, several characteristics of amyloid-induced Alzheimer's disease pathology are not well established, especially in mice. The present study aimed to develop a new Alzheimer's disease model by investigating how Aß can be effectively aggregated using prokaryotes and eukaryotes. To express the Aß42 complex in HEK293 cells, we cloned the Aß42 region in a tandem repeat and incorporated the resulting construct into a eukaryotic expression vector. Following transfection into HEK293 cells via lipofection, cell viability assay and western blotting analysis revealed that exogenous Aß42 can induce cell death and apoptosis. In addition, recombinant His-tagged Aß42 was successfully expressed in Escherichia coli BL21 (DE3) and not only readily formed Aß complexes, but also inhibited the proliferation of SH-SY5Y cells and E. coli. For in vivo testing, recombinant His-tagged Aß42 solution (3 µg/µl in 1× PBS containing 1 mM Ni²âº) was injected stereotaxically into the left and right lateral ventricles of the brains of C57BL/6J mice (n = 8). Control mice were injected with 1× PBS containing 1 mM Ni²âº following the same procedure. Ten days after the sample injection, the Morris water maze test confirmed that exogenous Aß caused an increase in memory loss. These findings demonstrated that Ni²âº is capable of complexing the 50-kDa amyloid and that intracerebroventricular injection of Aß42 can lead to cognitive impairment, thereby providing improved Alzheimer's disease models.
