Mechanisms underlying intravenous transplantation of human amniotic mesenchymal stem cells for Alzheimer's disease in transgenic APP super(+) mice

BACKGROUND: APP gene is closely associated with the onset of Alzheimer' disease. Intravenous transplantation of human amniotic mesenchymal stem cell (AMSCs) can promote the learning and memory improvement in transgenic APP super(+) mice with Alzheimer' disease. OBJECTIVE: To study whether the AMSCs can transfer into the brain tissue of Alzheimer's disease mice, and differentiate into the neural cell, then cure the disease after the human AMSC transplantation via tail venous injection. METHODS: Human AMSCs were isolated in vitro sterilely. At the third passage, 0.5 mL single cell suspension at 1x10 super(9)/L was obtained and transplanted by tail venous pathway in transplantation group mice, Mice in the control group were injected with an equal volume of saline. APP-gene mice in the normal group were left intact. 5'-bromo-2-deoxyuridine (BrdU) labeled third-generation AMSCs expression was detected in mice brain tissue by immunohistochemical method. Glial fibrillary acidic protein (GFAP), Nestin and neuron specific enolase (NSE) expression was measured in the brain tissue of mice from each group. RESULTS AND CONCLUSION: Under an optical microscope, a majority of nuclei in the brain tissue of mice from transplantation group were stained blue, but some nuclei were stained brown, positive for BrdU. Compared with control group, the expression of GFAP in the brain tissue of transplanted mice was increased about 4 times, even more than in the normal group (P < 0.05). The expression of Nestin in the brain tissue of transplanted mice was increased about 10%, but still lower than the normal group nearly 20% (P < 0.05). NSE expression was decreased by 1/3, but still higher compared with the normal group (P < 0.05). Above-mentioned results have shown that human AMSC transplantation for treating Alzheimer's disease takes place by AMSCs homing to APP super(+) mouse brain tissue and differentiating into neural cells.