Abstract
Objective:
In this study, we investigated the dynamic distribution processes of Mn2+ in rat brain using magnetic resonance imaging (MRI) after an intra-arterial (IA) injection of MnCl2 and following the breaking of the blood–brain barrier (BBB).
Methods:
Adult male Sprague-Dawley (SD) rats were employed in the study. After the rats were anesthetized with urethane, 25% mannitol was administrated into the right internal carotid artery (ICA) in order to disrupt the BBB, 50 mmol/l (10 mg/kg) of MnCl2 was then injected into ICA prior to the MRI assay. The MRI was performed at 7 T for a continuous 2 hours following the administration of MnCl2. Image reconstruction and analysis were performed using the Statistical Parametric Mapping (SPM) software.
Results:
As time progressed, the Mn2+ enhanced signal intensity showed a gradual increase with a maximum increase at 10 minutes following MnCl2 administration, and began to decline after 10 minutes. From 30 minutes to 2 hours, the signal-enhanced region became more homogeneous, and the signal-enhanced range spread to the contralateral area up to 2 hours after MnCl2 administration.
Conclusion:
These results will help future research to select an appropriate time point to perform functional MRI for different types of activity-induced manganese (AIM) MRI research studies. These findings will allow researchers to discriminate intended, stimulation-specific enhanced signal from unintended, nonspecific enhanced signals.
Acknowledgements
This study was funded by the National Science Fund of China (No. 81171179,81272439, 31300921), the Funds for Key Sci-Tech Research Projects of Guangdong (No.2008A030201019) and Guangzhou (No. 09B52120112-2009J1-C418-2, No. 2008A1-E4011-6).