title: Manganese-enhanced MRI detection of neurodegeneration in neonatal hypoxic-ischemic cerebral injury.
abstract: In this study, we investigated the Mn-enhanced MRI (MEMRI) for detecting neurodegenerative processes in neonatal hypoxic-ischemic (H-I) cerebral injury. Seven-day-old rats were induced with H-I injury, and scanned for T1-weighted image (T1WI) and T2-weighted image (T2WI) with and without systemic MnCl2 administration. Serial histological analysis was performed for Mn-superoxide dismutase (Mn-SOD) and glutamine synthetase (GS), which are Mn-binding enzymes against the oxidative stress and glutamate excitotoxicity in neurodegeneration. In the acute phase (first 2 days), the ipsilateral lesion exhibited no Mn enhancement in T1WIs, with histology showing no Mn-SOD and GS production. In the mid-phase (from day 3), Mn enhancement was found in the cortex, basal ganglia, and hippocampus, correlating with local Mn-SOD and GS increase. In the late phase, the enhancement became more localized to the pericyst basal ganglia and cortex, and then gradually diminished. In T2WIs, a signal decrease was observed from day 3 in the corresponding regions. Hypointense voids gradually formed in the late phase, correlating with the local iron accumulation. H-I rats without Mn2+ administration exhibited similar but weak changes in T1WIs and T2WIs from days 14 and 7, respectively. These results indicate that Mn2+ may be a useful in vivo probe for monitoring Mn-SOD and GS enzymatic activities.
authors.affiliation: Laboratory of Biomedical Imaging and Signal Processing, Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong.
authors.forename: Jian
authors.initials: J
authors.lastname: Yang
authors.forename: Pek-Lan
authors.initials: PL
authors.lastname: Khong
authors.forename: Yanxin
authors.initials: Y
authors.lastname: Wang
authors.forename: Andrew Chi-Yuen
authors.initials: AC
authors.lastname: Chu
authors.forename: Shu-Leong
authors.initials: SL
authors.lastname: Ho
authors.forename: Pik-To
authors.initials: PT
authors.lastname: Cheung
authors.forename: Ed X
authors.initials: EX
authors.lastname: Wu
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002712:Chlorides; D003287:Contrast Media; D005974:Glutamate-Ammonia Ligase / Q000378:metabolism; D020925:Hypoxia-Ischemia, Brain / Q000201:enzymology / Q000378:metabolism / Q000473:pathology*; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D017895:Manganese Compounds; D018384:Oxidative Stress; D051381:Rats; D017207:Rats, Sprague-Dawley; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D002712:Chlorides; D003287:Contrast Media; D017895:Manganese Compounds; D013482:Superoxide Dismutase; D005974:Glutamate-Ammonia Ligase; C025340:manganese chloride