Striatal grafts in a rat model of Huntington's disease: Time course comparison of MRI and histology

Survival and integration into the host brain of grafted tissue are crucial factors in neurotransplantation approaches. The present study explored the feasibility of using a clinical MR scanner to study striatal graft developm ent in a rat model of Huntington's disease. Rat fetal lateral ganglionic em inences grown as free-floating roller-tube cultures were grafted into the q uinolinic acid-lesioned striatum, and T1- and T2-weighted sequences were ac quired at 2, 7, 21, and 99 days posttransplantation. MR images were then co mpared with images of corresponding histological sections. The lesion-induc ed striatal degeneration caused a progressive ventricle enlargement, which was significantly different from controls at 21 days posttransplantation. S even days posttransplantation, T1-weighted images revealed a defined liquid -isointense signal surrounded by a hyperintense rim at the site of graft pl acement, which was found unaltered for the first 21 days posttransplantatio n, whereas a hypointense graft signal was detected at 99 days posttransplan tation. At 2 days posttransplantation, T2-weighted images showed the graft region as a hyperintense area surrounded by a rim of low signal intensity b ut at later time-points graft location could not be further verified. Measu res for graft size and ventricle size obtained from MR images highly correl ated with measures obtained from histologically processed sections (R = 0.8 , P < 0.001). In conclusion, the present study shows that fetal rat lateral ganglionic eminences grown as free-floating roller-tube cultures can be su ccessfully grafted in a rat Huntington model and that a clinical MR scanner offers a useful noninvasive tool for studying striatal graft development. (C) 1999 Academic Press.