Learning Deficits Accompanied by Microglial Proliferation After the Long-Term Post-Injection of Alzheimer’s Disease Brain Extract in Mouse Brains

Background: Human tauopathy brain injections into the mouse induce development of tau aggregates, which spread to functionally connected regions; however, features this neurotoxicity remain unclear. One reason may be short observational periods because previous studies mostly used mutated-tau transgenic mice and needed complete study before these developed neurofibrillary tangles. Objective: To examine whether long-term incubation Alzheimer’s disease (AD) in cause functional decline. Methods: We herein Tg601 mice, overexpress wild-type human tau, non-transgenic littermates (NTg) injected an insoluble fraction AD unilateral hippocampus. Results: After a (17–19 months) post-injection, exhibited learning deficits detected by Barnes maze test. Aggregated pathology bilateral hippocampus was more prominent than NTg mice. No significant changes were observed number Neu-N positive cells or astrocytes hippocampus, whereas that Iba-I-positive microglia increased after injection. Conclusion: These results potentially implicate propagation decline indicate non-mutated reflect pathological conditions.