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Updated: Apr 8, 2026
Author Spotlight: Establishing a Reliable Distal MCA Occlusion Model in Mice for Stroke Research
Published on: December 15, 2023
MRI heralds secondary nigral lesion after brain ischemia in mice: a secondary time window for neuroprotection
Vincent Prinz1,2,3, Anna-Maria Hetzer1,2, Susanne Müller2
1Klinik und Poliklinik für Neurologie, Charité-Universitätsmedizin Berlin, Berlin, Germany.
Abstract:
Cerebral ischemia in the territory of the middle cerebral artery (MCA) can induce delayed neuronal cell death in the ipsilateral substantia nigra (SN) remote from the primary ischemic lesion. This exofocal postischemic neuronal degeneration (EPND) may worsen stroke outcomes. However, the mechanisms leading to EPND are poorly understood. Here, we studied the time course of EPND via sequential magnetic resonance imaging (MRI) and immunohistochemistry for up to 28 days after 30 minutes' occlusion of the MCA (MCAo) and reperfusion in the mouse. Furthermore, the effects of delayed treatment with FK506 and MK-801 on the development of EPND were investigated. Secondary neuronal degeneration in the SN occurred within the first week after MCAo and was characterized by a marked neuronal cell loss on histology. Sequential neuroimaging examinations revealed transient MRI changes, which were detectable as early as day 4 after MCAo and thus heralding histologic evidence of EPND. Treatment with MK-801, an established anti-excitotoxic agent, conferred protection against EPND even when initiated days after the initial ischemic event, which was not evident with FK506. Our findings define a secondary time window for delayed neuroprotection after stroke, which may provide a promising target for the development of novel therapies.
Insights
Delayed neuronal cell death after stroke, known as exofocal postischemic neuronal degeneration (EPND), can be targeted for treatment. MK-801 demonstrated neuroprotection against EPND, suggesting a therapeutic window for stroke recovery.
Area of Science:
- Neuroscience
- Ischemic Stroke Research
- Neurodegeneration
Background:
- Cerebral ischemia, particularly middle cerebral artery occlusion (MCAo), can cause delayed neuronal cell death in the substantia nigra (SN).
- This exofocal postischemic neuronal degeneration (EPND) remote from the primary lesion can worsen stroke outcomes.
- The underlying mechanisms of EPND remain largely unknown.
Purpose of the Study:
- To investigate the temporal profile of EPND following MCAo in a mouse model.
- To evaluate the efficacy of delayed treatment with FK506 and MK-801 on EPND.
- To identify potential therapeutic time windows for neuroprotection after stroke.
Main Methods:
- Sequential magnetic resonance imaging (MRI) and immunohistochemistry were employed for up to 28 days post-MCAo.
- Mice underwent 30 minutes of MCAo followed by reperfusion.
- Delayed administration of FK506 and MK-801 was assessed for neuroprotective effects.
Main Results:
- Significant neuronal cell loss in the SN was observed within the first week after MCAo.
- MRI detected transient changes as early as day 4, preceding histological evidence of EPND.
- MK-801 treatment, initiated days after MCAo, provided significant protection against EPND, unlike FK506.
Conclusions:
- EPND develops within the first week following MCAo and is detectable by MRI.
- A delayed therapeutic window for neuroprotection against EPND exists.
- MK-801 shows promise for treating EPND, highlighting a potential therapeutic strategy for stroke recovery.
