Comparative in vivo and pathological analysis of the blood-brain barrier in mouse telencephalic transplants.

The post-transplantation status of the blood-brain barrier (BBB) is still a matter of debate. In an attempt to define BBB properties after neural transplantation in mice of a defined genetic background, we have used two exogenous markers (horseradish peroxidase and Evans blue), one endogenous marker (immunoglobulins), and in vivo contrast enhanced magnetic resonance imaging (MRI) and compared the results obtained with the different methods. With all four techniques employed, we found the BBB to be reconstituted in 67% of the grafts 3 weeks after grafting, and in more than 90% of all grafts 50 days after grafting. Horseradish peroxidase and contrast enhanced MRI were the most sensitive techniques, the latter offering the unique advantage of repetitive scanning of individual grafts. Our findings provide important information for transplantation studies in mouse models for neurodegenerative diseases.