In vivo magnetic resonance imaging of embryonic neural grafts in a rat model of striatonigral degeneration (multiple system atrophy)

The effects of embryonic neural transplantation in experimental models of n eurodegenerative disorders are commonly assessed by behavioral tests and po stmortem neurochemical or anatomical analysis. The purpose of the present s tudy was to evaluate embryonic neuronal grafts in a novel rat model of mult iple system atrophy (MSA) with the help of in vivo magnetic resonance imagi ng (MRI) and to correlate imaging with histological parameters. Striatonigr al double lesions were created in male Wistar rats by unilateral intrastria tal injection of 3-nitropropionic acid (3-NP). Seven weeks following lesion surgery animals were divided into four transplantation groups receiving ei ther pure mesencephalic, pure striatal, mesencephalic-striatal cografts, or sham grafts. In vivo structural imaging was performed 21 weeks after trans plantation using a whole body 1.5 Tesla MR scanner. The imaging protocol co mprised Ta-weighted TSE and T1-weighted TIR sequences. Immunohistochemistry using DARPP-32 as striatal marker and tyrosinhydroxylase as marker for nig ral neurons was performed for correlation analysis of imaging and histologi cal parameters. The sensitivity of graft detection by in vivo MRI was 100%. The graft tissue was clearly demarcated from the remaining striatal tissue in both T2- and T1-weighted sequences. Morphometrically, cross-sectional a reas of the grafts and spared intact striatum as defined by immunohistochem istry correlated significantly with measurements obtained by in vivo MRI. I n conclusion, we were able to evaluate in vivo both lesion-induced damage a nd graft size in a 3-NP rat model of MSA using a conventional whole body 1. 5 Tesla MRI scanner. Additionally, we obtained an excellent correlation bet ween MRI and histological measurements, (C) 2000 Academic Press.