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Behavioral changes after focal cerebral ischemia by left middle cerebral artery occlusion in rats
M Yamamoto1, A Tamura, T Kirino
1Department of Pharmacology, Yamanouchi Pharmaceutical Co. Ltd., Tokyo, Japan.
Abstract:
Behavioral changes after occlusion of the left middle cerebral artery (MCA) in rats were investigated for 16 weeks. Impairment of motor coordination and incidence of neurological deficits including hemiplegia and abnormal posture were present for the first 2 and 4 weeks after MCA occlusion, respectively. Learning behavior in one-trial passive avoidance task was disturbed for the entire 16-week period when rats were trained at days 3 after MCA occlusion. Reacquisition was also impaired when rats were retrained on 8 weeks after MCA occlusion. Except for synchronized EEG at days 2 after MCA occlusion, significant changes in spontaneous movement and EEG were not observed in the MCA-occluded group. These results suggest that this rat model of MCA-occlusion is useful for quantitatively measuring functional changes in chronic phase of focal cerebral ischemia.
Insights
This study shows that middle cerebral artery (MCA) occlusion in rats causes lasting motor and learning deficits for up to 16 weeks. This rat model effectively captures chronic functional changes in focal cerebral ischemia.
Area of Science:
- Neuroscience
- Cerebrovascular Research
- Animal Models
Background:
- Focal cerebral ischemia, often caused by middle cerebral artery (MCA) occlusion, leads to significant neurological deficits.
- Understanding the long-term behavioral consequences is crucial for developing effective therapeutic strategies.
- Rodent models are essential for studying the pathophysiology and recovery from ischemic stroke.
Purpose of the Study:
- To investigate the chronic behavioral alterations following left middle cerebral artery (MCA) occlusion in a rat model.
- To quantitatively assess motor coordination, neurological deficits, and learning/memory impairments over a 16-week period.
- To evaluate the utility of this MCA occlusion model for studying the chronic phase of focal cerebral ischemia.
Main Methods:
- Induction of left middle cerebral artery (MCA) occlusion in adult male rats.
- Behavioral testing including motor coordination, neurological deficit scoring, and a one-trial passive avoidance task.
- Electrophysiological recordings (EEG) and assessment of spontaneous movement at various time points post-occlusion.
Main Results:
- Rats exhibited impaired motor coordination and neurological deficits (hemiplegia, abnormal posture) for the initial 2-4 weeks post-MCA occlusion.
- Learning and memory, assessed via passive avoidance, were significantly disturbed throughout the entire 16-week study period, including impaired reacquisition.
- No significant changes in spontaneous movement or EEG were observed, except for synchronized EEG at 2 days post-MCA occlusion.
Conclusions:
- The MCA occlusion rat model demonstrates persistent functional deficits relevant to chronic focal cerebral ischemia.
- This model is suitable for quantitative assessment of long-term behavioral and cognitive impairments after ischemic stroke.
- Findings highlight the prolonged impact of MCA occlusion on motor function and learning, underscoring the need for chronic phase research.