Effects of human amnion membrane mesenchymal stem cell transplantation on behavior and beta-amyloid protein changes in transgenic mice with Alzheimer's desease

Background: APP gene is closely associated with the onset of Alzheimer's disease. β-amyloid is the main ingredient of senile plaque in the brain of Alzheimer's disese patients. Gene mutation and environment can destroy the dynamic balance of β -amyloid, resulting in the occurrence and development of Alzheimer's disease. Objective: To study the effects of human ammotic membrane derived mesenchymal stem cell transplantation via tail venous injection on the capacity of learning, memory and 2b -amyloid changes in Alzheimer's transgenic mice. Design Time and Setting: The randomized controlled experiment was performed at the Department of Microbiology and Immunology, Zhengzhou University and Henan Institute of Traditional Chinese Medicine from May to October 2008. Materials: The ammon membrance was harvested from healthy puerperants were supplied by Department of Obstetrics, First Affiliated Hospital, Zhengzhou University. A total of 29 APP trangenic mice and 9 APP-trangenic mice, identified by polymerase chain reaction served as normal group. A total of APP+ trangenic mice were equally and randomly assigned into cell transplantation group and control group. Methods: Human amnion membrane derived mesenchymal stem cells were sterilely isolated and cultured. The third passages of cells (1x10⁹/L) (0.5 mL) were transplanted by tail venous pathway to mice. Mice in the control group were injected with an equal volume of saline, whereas mice in the normal group were left intact. Main Outcome Measures: Morris water maze method was adopted to detect the escaping latency, crossing platform times and platform quadrant. Congo red staining was utilized to observe β -amyloid expression in mouse brain tissues. Results: Before transplantation, in location navigation tests, there were significant differences in escaping latency in the cell transplantation group and control group compared with the normal group (P < 0.05). At 2 weeks following transplantation, the escaping latency was similar in the cell transplantation group and the normal group (P > 0.05), which was significantly shorter than in the control group (P < 0.05). In the exploration experiment, no significant difference was detected in crossing platform times and platform quadrant before and after transplantation (P > 0.05). At 1 month following transplantation, no or few β -amyloid expression was found in the normal group. β -amyloid expression was significantly less in the cell transplantation group than in the control group. Conclusion: Human amniotic membrane mesenchymal stem cell transplantation through the tail vein could promote the learning and memory ability in space and reduce β -amyloid expression in the brain in Alzheimer's disease mice.