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Microsurgical intraluminal middle cerebral artery occlusion model in rodents
1National Center of Scientific Research, CNRS, UPR 9023, Montpellier, France. ardehali_mr@yahoo.fr
Objectives:
Focal brain ischemia induced in rodents by occlusion of the middle cerebral artery (MCA) is a widely used paradigm of human brain infarct. The objective of this study is to compare the effectiveness and reproducibility of MCA filament occlusion model in rats and mice.
Materials And Methods:
A total of 140 rodents (69 rats and 71 mice) were operated. Ninety-five animals were subjected to MCA occlusion; the surgical procedure consisted of introducing an uncoated surgical nylon monofilament into the cervical common carotid artery (CCA) and advancing it intracranially to permanently block blood flow into the right MCA. Forty-five sham-occluded rodents underwent CCA ligation. Surgical success, autopsy confirmed success and mortality rate were evaluated. Effective MCA occlusion was confirmed by the evidence of motor neurological deficit, by histopathology, immunohistochemistry (IHC) and reverse transcriptase-polymerase chain reaction (RT-PCR). IHC was performed in a randomly selected number of animals to detect the protein product of monocyte chemoattractant protein-1. The brain tissue in mice was examined by RT-PCR for the expression of macrophage inflammatory protein-1 alpha mRNA.
Results:
Surgical success rate was 89% in the rats, significantly lower than that in the mice (100%, P < 0.05). Autopsy confirmed success rate in the rats, 60%, was also significantly different from that in the mice (92.5%, P < 0.001). The operative mortality rate was 4.3% in the rats and 15% in the mice.
Conclusion:
The present study demonstrates that the microsurgical filament occlusion of the MCA can be more successfully performed in mice. The lower rate of success in rats seems to be as a result of the architecture of the carotid canal in this animal. No previous reports, using a considerable number of animals, have compared the feasibility of intraluminal model in the rat with that in the mouse.
Insights
The middle cerebral artery (MCA) filament occlusion model for inducing brain ischemia is more effective and reproducible in mice than in rats. This study highlights mice as a superior model for stroke research due to higher surgical success rates.
Area of Science:
- Neuroscience
- Stroke Research
- Animal Models
Background:
- Focal brain ischemia models are crucial for studying human stroke.
- The middle cerebral artery (MCA) occlusion is a common method to induce focal brain ischemia in rodents.
- Comparing the efficacy of MCA occlusion models between rats and mice is essential for optimizing preclinical stroke research.
Purpose of the Study:
- To compare the effectiveness and reproducibility of the MCA filament occlusion model in rats and mice.
- To evaluate surgical success rates, autopsy-confirmed success, and mortality rates for MCA occlusion in both species.
- To provide insights into the feasibility of using rodent models for stroke research.
Main Methods:
- A total of 140 rodents (69 rats, 71 mice) underwent MCA filament occlusion or sham procedures.
- Surgical success was assessed by successful MCA blockage and confirmed by neurological deficits, histopathology, IHC, and RT-PCR.
- Autopsy confirmation, mortality rates, and specific molecular markers (MCP-1, MIP-1 alpha) were evaluated.
Main Results:
- Surgical success rate was significantly higher in mice (100%) compared to rats (89%).
- Autopsy-confirmed success rates were also significantly higher in mice (92.5%) versus rats (60%).
- Operative mortality was lower in rats (4.3%) than in mice (15%).
Conclusions:
- Microsurgical filament occlusion of the MCA is more successfully performed in mice.
- The lower success rate in rats may be attributed to the carotid canal's anatomy.
- This study provides a comparative analysis of MCA intraluminal occlusion feasibility in rats and mice using a substantial number of animals.