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Updated: Jun 5, 2026
A Magnetic Resonance Imaging Protocol for Stroke Onset Time Estimation in Permanent Cerebral Ischemia
Published on: September 16, 2017
[Experimental study of hippocampal neuronic lesion in ischemic rat by magnetic resonance spectroscopy]
Hai-Yan Lou1, Min-Ming Zhang, Jing-Feng Zhang
1Department of Radiology, The First Affiliated Hospital, College of Medicine, Zhejiang Uninersity, Hangzhou 310003, China.
Aim:
To evaluate N-acetylaspartate reflecting the neuronal lesion in middle cerebral artery occlusion and reperfusion rat by magnetic resonance spectroscopy (MRS).
Methods:
Sixteen adult Wistar rats with MCAO reperfusion and ten pseudooperation rats were performed MRS in vivo at the sixth weeks, then pathologic examination of HE staining and immunohistochemical staining were made. We compared hippocampus modality, cell density and immunohistochemical results with N-acetylaspartate, creatine changes and ration of NAA/Cr.
Results:
The values of NAA, Cr and NAA/Cr of ipsilateral hippocampus lesion in MCAO reperfusion rats (2.05 +/- 0.33, 2.42 +/- 0.41 and 0.86 +/- 0.10) were visiblly decreased than contralateral hippocampus (3.45 +/- 0.58, 3.10 +/- 0.93, 1.18 +/- 0.32) and control group (3.42 +/- 0.43, 3.57 +/- 0.47, 0.98 +/- 0.14). But the level of decreased NAA is not corresponding to the degree of neuronal death in ipsilateral region of hippocampus in histochemistry.
Conclusion:
MRS has perfect explanation of cell metabolic changes in CA1 region. Decrease of NAA represented neuron delayed injury. But the decreased level of NAA is not perfectly corresponded to the degree of neuron lost. This change has closed correlation with reactive astrocytes proliferation.
Insights
Magnetic resonance spectroscopy (MRS) revealed decreased N-acetylaspartate (NAA) in rats after middle cerebral artery occlusion and reperfusion, indicating delayed neuronal injury. However, NAA levels did not perfectly correlate with neuronal loss, suggesting involvement of reactive astrocytes.
Area of Science:
- Neuroscience
- Biochemistry
- Medical Imaging
Context:
- Middle cerebral artery occlusion and reperfusion (MCAO) is a common cause of ischemic stroke.
- Neuronal damage and loss are key pathological features of stroke.
- Magnetic resonance spectroscopy (MRS) is a non-invasive technique to assess brain metabolites.
Purpose:
- To evaluate N-acetylaspartate (NAA) as a marker of neuronal injury in a rat model of MCAO and reperfusion using MRS.
- To correlate MRS findings with histopathological examinations.
Summary:
- MRS revealed significantly decreased levels of N-acetylaspartate (NAA) and creatine (Cr), as well as the NAA/Cr ratio, in the ipsilateral hippocampus of MCAO reperfusion rats compared to the contralateral side and control groups.
- Histopathological analysis showed that the decrease in NAA did not precisely correspond to the extent of neuronal death in the affected hippocampus.
- The observed changes in NAA levels correlated with reactive astrocyte proliferation.
Impact:
- MRS can detect metabolic changes indicative of delayed neuronal injury following MCAO.
- NAA levels, while reflecting neuronal damage, may not be a sole indicator of neuronal loss severity.
- Findings suggest a role for reactive astrocytes in the observed metabolic alterations post-stroke.
