Related Experiment Videos
The macrosphere model: evaluation of a new stroke model for permanent middle cerebral artery occlusion in rats
Tibo Gerriets1, Fuhai Li, Matthew D Silva
1Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01655, USA. gerriets@hotmail.com
Background And Purpose:
The suture middle cerebral artery occlusion (MCAO) model is widely used for the simulation of focal cerebral ischemia in rats. This technique causes hypothalamic injury resulting in hyperthermia, which can worsen outcome and obscure neuroprotective effects. Herein, we introduce a new MCAO model that avoids these disadvantages.
Methods:
Permanent MCAO was performed by intraarterial embolization using six TiO(2) macrospheres (0.3-0.4 mm in diameter) or by the suture occlusion technique. Body temperature was monitored, functional and histologic outcome was assessed after 24 h. Additional 16 rats were subjected to macrosphere or suture MCAO. Lesion progression was evaluated using magnetic resonance imaging (MRI).
Results:
The animals subjected to suture MCAO developed hyperthermia (>39 degrees C), while the temperature remained normal in the macrosphere MCAO group. Infarct size, functional outcome and model failure rate were not significantly different between the groups. Lesion size on MRI increased within the first 90 min and remained unchanged thereafter in both groups.
Conclusions:
The macrosphere MCAO model provides reproducible focal cerebral ischemia, similar to the established suture technique, but avoids hypothalamic damage and hyperthermia. This model, therefore, may be more appropriate for the preclinical evaluation of neuroprotective therapies and can also be used for stroke studies under difficult conditions, e.g., in awake animals or inside the MRI scanner.
Insights
A new macrosphere middle cerebral artery occlusion (MCAO) model in rats avoids hyperthermia seen in suture MCAO. This improved model offers reproducible focal cerebral ischemia for neuroprotection studies.
Area of Science:
- Neuroscience
- Cerebrovascular Research
- Animal Models
Background:
- The suture middle cerebral artery occlusion (MCAO) model is standard for studying focal cerebral ischemia in rats.
- This method often causes hypothalamic injury, leading to hyperthermia, which complicates outcome assessment and obscures neuroprotective effects.
Purpose of the Study:
- Introduce and evaluate a novel MCAO model using macrospheres to circumvent the disadvantages of the suture technique.
- Assess the suitability of the macrosphere MCAO model for preclinical neuroprotection research.
Main Methods:
- Permanent MCAO was induced using intraarterial embolization with TiO(2) macrospheres or the traditional suture technique.
- Body temperature, functional outcomes, and histological results were monitored and assessed 24 hours post-MCAO.
- Lesion progression was tracked using magnetic resonance imaging (MRI) in a subset of animals.
Main Results:
- Macrosphere MCAO maintained normal body temperature, unlike the suture MCAO group which developed hyperthermia (>39°C).
- Infarct size, functional deficits, and model failure rates were comparable between the macrosphere and suture MCAO groups.
- MRI revealed lesion development within 90 minutes for both models, with no significant further progression.
Conclusions:
- The macrosphere MCAO model reliably induces focal cerebral ischemia without causing hyperthermia, offering an advantage over the suture method.
- This technique is a valuable alternative for preclinical evaluation of neuroprotective therapies and for stroke research in challenging conditions, such as in awake or MRI-imaged animals.