Conclusion
UTMD assisted dual delivery of Aβ antibody and NSCs crossing the BBB into AD mice brain could help to clear Aβ plaques, increase the expression of BDNF, and restore the impaired neural function. This finding may offer potential insight into treatment of AD.
Methods
Twenty-seven APP/PS1 double transgenic mice (Tg mice) and 33 wild-type mice were used. Wild-type mice were insonated by diagnostic ultrasound with microbubbles (MB) for 5 min to observe the blood brain barrier (BBB) opening. The survival situation of engrafted NSCs crossing the opened BBB mediated by UTMD in Tg mice was evaluated by in vivo imaging system. We further explored the combination therapy effects of UTMD mediated Aβ antibody and NSCs dual delivery. Tg mice in each group were exposed to diagnostic ultrasound for 5 min once a week for four times, with MB, MBAβ , and/or NSCs administration according to groups. Cognition and memory functions were explored by Morris water maze test, Aβ plaques deposition was evaluated by immunohistochemical, and brain-derived neurotrophic factor (BDNF) and synaptophysin (SYN) expression were detected by western blot and immunofluorescence.
Results
BBB was opened mediated by diagnostic ultrasound with MB, and the duration of opening was about 10 h. The transplanted NSCs survived in Tg mice for no more than 72 h. Compared with control group, the Tg mice in combined delivery of NSCs and Aβ antibody by UTMD group improved memory function and spatial learning with shorter latency to find the platform, longer distance traveled, and longer time spent in targeted quadrant, and more crossing times (p < 0.05). Besides, the combination delivery group promoted the clearance of Aβ plaques compared with control group both in hippocampus (p < 0.01) and cortex (p < 0.05). Moreover, the expression of BDNF in combination delivery group was significantly higher than that in control group and ultrasound-mediated MB group (p < 0.05). No significant change of SYN was observed in each group.