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Two-vessel Occlusion Mouse Model of Cerebral Ischemia-reperfusion
Published on: March 1, 2019
Cerebral Ischemia Changed the Effect of Metabosensitive Muscle Afferents on Somatic Reflex Without Affecting Thalamic
Caroline Pin-Barre1, Christophe Pellegrino2, Frédéric Laurin3
1Aix Marseille Univ, CNRS, ISM, Marseille, France.
Abstract:
The purpose of the present study was to examine the contribution of group III and IV metabosensitive afferents at spinal and supraspinal levels in rats subjected to middle cerebral artery occlusion (MCAO) with reperfusion during the acute phase. Animals were randomized in Control (n = 23), SHAM (n = 18), MCAO-D1 (n = 10), and MCAO-D7 (n = 20) groups. Rats performed the Electrical Von Frey and the Adhesive removal tests before the surgery and at day 1 (D1), D3, and D7 after MCAO. Animals were subjected to electrophysiological recordings including the responses of group III/IV metabosensitive afferents to combinations of chemical activators and the triceps brachii somatic reflex activity at D1 or D7. The response of ventral posterolateral (VPL) thalamic nuclei was also recorded after group III/IV afferent activation. Histological measurements were performed to assess the infarct size and to confirm the location of the recording electrodes into the VPL. Behavioral results indicated that MCAO induced disorders of both mechanical sensibility and motor coordination of paretic forepaw during 7 days. Moreover, injured animals exhibited an absence of somatic reflex inhibition from the group III/IV afferents at D1, without affecting the response of both these afferents and the VPL. Finally, the regulation of the central motor drive by group III/IV afferents was modified at spinal level during the acute phase of cerebral ischemia and it might contribute to the observed behavioral disturbances.
Insights
Group III and IV metabosensitive afferents are crucial for motor control after stroke. Their altered spinal regulation contributes to behavioral deficits following middle cerebral artery occlusion (MCAO) in rats.
Area of Science:
- Neuroscience
- Physiology
- Stroke Research
Background:
- Middle cerebral artery occlusion (MCAO) in rats is a model for ischemic stroke.
- Group III and IV metabosensitive afferents play a role in sensory and motor functions.
- The contribution of these afferents at spinal and supraspinal levels during acute stroke is not fully understood.
Purpose of the Study:
- To investigate the role of group III and IV metabosensitive afferents in rats after MCAO.
- To examine their contribution at both spinal and supraspinal levels during the acute phase of cerebral ischemia.
Main Methods:
- Rats underwent MCAO and were divided into control, SHAM, and MCAO groups at different time points (D1, D7).
- Behavioral tests (Electrical Von Frey, Adhesive removal) assessed mechanical sensibility and motor coordination.
- Electrophysiological recordings evaluated afferent responses, somatic reflex activity, and ventral posterolateral (VPL) thalamic nuclei responses.
- Histological analysis determined infarct size and electrode placement.
Main Results:
- MCAO induced deficits in mechanical sensibility and motor coordination of the paretic forepaw for 7 days.
- Somatic reflex inhibition by group III/IV afferents was absent at D1 post-MCAO.
- Afferent and VPL responses remained unaffected, but central motor drive regulation by these afferents was altered at the spinal level.
Conclusions:
- Group III/IV afferent function is modified at the spinal level during acute cerebral ischemia.
- This altered spinal regulation may contribute to the observed behavioral disturbances after MCAO.
- Further research is needed to elucidate the precise mechanisms involved.
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