Background: Mesenchymal stem cell transplantation is demonstrated to improve neurological
performance in neurodegenerative diseases including Alzheimer’s disease.
Objective: The objective of this study is to understand the underlying mechanism of such improvement.
Methods: Amyloid β (Aβ) peptide was infused into the lateral ventricle of adult Wister rats using the
osmotic pump. After 15 days of continuous infusion, a mesenchymal stem cell line (B10) was transplanted
in the lateral ventricle. Learning-related behavior was evaluated by 2-way shuttle avoidance test.
Fifteen days after B10 transplantation, pathological and expressional changes were evaluated.
Results: Compared to sham group, learning-related behavior was significantly decreased in Aβ-infused
non-transplanted group, but not in B10-transplanted group. Nissl staining results demonstrated that the
number of hippocampal pyramidal neurons in CA1 area in B10-transplanted group was similar to the
sham group, whereas that was decreased in Aβ-infused non-transplanted group. Aβ mainly deposited in
the vessels of the brains of Aβ-infused non-transplanted rats, which was decreased by B10 transplantation.
Moreover, B10 transplantation increased vessel density as well as endoglin positive cells. The
number of astrocyte and microglia was decreased in Aβ-infused non-transplanted group, which was returned
to the level of sham animals by B10 transplantation. Real-time PCR and immunostaining results
showed that B10 transplantation significantly increased IL-1β mRNA and protein expression.
Conclusion: Thus, our result showed that MSC transplantation effectively decreased Aβ deposition in
the cerebral vessel and increased angiogenesis, which could be a possible cause of improved neurological
performance in Aβ-infused AD model rats.