IN-VIVO 3-DIMENSIONAL MR MICROSCOPY OF MICE WITH CHRONIC RELAPSING EXPERIMENTAL AUTOIMMUNE ENCEPHALOMYELITIS AFTER TREATMENT WITH INSULIN-LIKE GROWTH-FACTOR-I

PURPOSE: The purpose of this study was to determine the ability of thr ee-dimensional in vivo MR microscopy to depict the treatment effects o f insulin-like growth factor-I (IGF-I) in SJL mice with chronic relaps ing experimental autoimmune encephalomyelitis (crEAE). METHODS: The ex periments were performed at 4.7-T on 10 crEAE mice and on one set of c ontrol animals. Five crEAE mice were treated with IGF-I and five were treated with a placebo. RESULTS: In the crEAE mice treated with the pl acebo, in vivo MR microscopy showed areas of abnormal signal throughou t the cerebrum, brain stem, and cerebellum. These findings were not pr esent in either the IGF-I-treated mice or the normal control animals. The diffuse alterations in signal intensity in the placebo-treated crE AE mice were not identified on histologic sections of the same areas. CONCLUSION: Differences between the IGF-I-and placebo-treated groups m ay reflect changes in stabilization or permeability of cell membranes and/or of the blood-brain barrier, although other alternative contrast mechanisms could be playing a role. In vivo MR microscopy depicted ch anges resulting from treatment of crEAE with IGF-I.