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Precise Characterization of the Penumbra Revealed by MRI: A Modified Photothrombotic Stroke Model Study.

Qian C, Li PC, Jiao Y, Yao HH, Chen YC, Yang J, Ding J, Yang XY, Teng GJ - PLoS ONE (2016)

Bottom Line: One hour after occlusion, the low perfusion areas on the perfusion-weighted imaging interlaced with the hypointense areas on the apparent diffusion coefficient map, demonstrating that the penumbra was located both surrounding and inside the lesions.This phenomenon was subsequently confirmed by the c-fos and heart shock protein 90 staining.At early stages, the lesions were clearly identified on the apparent diffusion coefficient map; the volumes of the lesions on the diffusion-weighted imaging and T2-weighted imaging did not reach a maximum until 12 hours.

View Article: PubMed Central - PubMed

Affiliation: Jiangsu Key Laboratory of Molecular and Functional Imaging, Department of Radiology, Zhongda Hospital, Medical School, Southeast University, Nanjing, China.

ABSTRACT

Aims: To precisely characterize the penumbra by MRI based on a modified photothrombotic stroke mouse model.

Methods: The proximal middle cerebral artery was occluded by a convenient laser system in conjunction with an intravenous injection of Rose Bengal in mice. And the suture MCAO model was performed in seven mice as a comparison of the reproducibility. One hour after occlusion, the penumbra was defined in six random photothrombotic stroke mice by mismatch between perfusion-weighted imaging and the apparent diffusion coefficient map on a home-made workstation. After imaging, three random mice of them were chosen to perform the reperfusion surgery. And the other three mice were sacrificed to stain for several potential penumbra markers, such as c-fos and heart shock protein 90. In the remaining mice, the evolution of the lesions was detected on the apparent diffusion coefficient map, diffusion-weighted imaging and T2-weighted imaging at 1, 3, 6, 12 and 24 hours. After evaluating the neurological deficit scores, the brains were sectioned and stained by triphenyltetrazolium chloride and Nissl.

Results: The mice subjected to photothrombosis showed significant behavioral deficits. One hour after occlusion, the low perfusion areas on the perfusion-weighted imaging interlaced with the hypointense areas on the apparent diffusion coefficient map, demonstrating that the penumbra was located both surrounding and inside the lesions. This phenomenon was subsequently confirmed by the c-fos and heart shock protein 90 staining. The final T2-weighted images of the mice subjected to the reperfusion surgery were also consistent with the penumbra images at one hour. At early stages, the lesions were clearly identified on the apparent diffusion coefficient map; the volumes of the lesions on the diffusion-weighted imaging and T2-weighted imaging did not reach a maximum until 12 hours. The coefficient of variation (CV) of the final lesions in the photothrombotic stroke mice was 21.7% (0.08 of 0.37) on T2-weighted imaging and 27.8% (0.10 of 0.35) on triphenyltetrazolium chloride, representing a high reproducibility (n = 7). While the CV of the lesions in the MCAO stroke mice was only 70% (0.24 of 0.34, n = 4).

Conclusions: This study has provided a precise imaging definition of the penumbra based on a reproducible photothrombotic stroke mouse model.

No MeSH data available.


Related in: MedlinePlus

The reproducibility of infarct volume.A) The lesions at 24 hours after occlusion were showed on T2WI (left side) and TTC slices (right side). B) The relative lesion volumes on the TTC-stained slices showed no difference from those on T2WI (p>0.05). For Nissl staining, representative images contrasted the ipsilateral (C) and contralateral zone (D). The white arrows indicated that the nucleus of neurons appears with karyolysis and pyknosis in the lesion.
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pone.0153756.g003: The reproducibility of infarct volume.A) The lesions at 24 hours after occlusion were showed on T2WI (left side) and TTC slices (right side). B) The relative lesion volumes on the TTC-stained slices showed no difference from those on T2WI (p>0.05). For Nissl staining, representative images contrasted the ipsilateral (C) and contralateral zone (D). The white arrows indicated that the nucleus of neurons appears with karyolysis and pyknosis in the lesion.

Mentions: To evaluate the reproducibility of the stroke models, TTC-staining and T2WI were introduced to examine the final relative lesion volumes. The rVL in the photothrombotic stroke group in the TTC-stained slices showed no significant difference with that on T2WI at 24 hours (0.35±0.10 vs 0.37±0.08; p> 0.05) (Fig 3A and 3B). The CV of infarct volumes was 21.7% (0.08 of 0.37) on T2WI and 27.8% (0.10 of 0.35) on TTC, suggesting a high reproducibility of this model. The rVL in the MCAO group on T2WI at 24 hours was 0.34±0.24, and the CV of infarct volumes was 70% (0.24 of 0.34) (S1 Fig). Nissl-staining was further used to examine the neurons. The nuclei of neurons in the lesions appeared karyolytic and pyknotic, indicating a regional loss of pigmentation and tissue structure (Fig 3C). Histological abnormalities were not detected microscopically around the lesions or in the contralateral hemisphere (Fig 3D).


Precise Characterization of the Penumbra Revealed by MRI: A Modified Photothrombotic Stroke Model Study.

Qian C, Li PC, Jiao Y, Yao HH, Chen YC, Yang J, Ding J, Yang XY, Teng GJ - PLoS ONE (2016)

The reproducibility of infarct volume.A) The lesions at 24 hours after occlusion were showed on T2WI (left side) and TTC slices (right side). B) The relative lesion volumes on the TTC-stained slices showed no difference from those on T2WI (p>0.05). For Nissl staining, representative images contrasted the ipsilateral (C) and contralateral zone (D). The white arrows indicated that the nucleus of neurons appears with karyolysis and pyknosis in the lesion.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4836676&req=5

pone.0153756.g003: The reproducibility of infarct volume.A) The lesions at 24 hours after occlusion were showed on T2WI (left side) and TTC slices (right side). B) The relative lesion volumes on the TTC-stained slices showed no difference from those on T2WI (p>0.05). For Nissl staining, representative images contrasted the ipsilateral (C) and contralateral zone (D). The white arrows indicated that the nucleus of neurons appears with karyolysis and pyknosis in the lesion.
Mentions: To evaluate the reproducibility of the stroke models, TTC-staining and T2WI were introduced to examine the final relative lesion volumes. The rVL in the photothrombotic stroke group in the TTC-stained slices showed no significant difference with that on T2WI at 24 hours (0.35±0.10 vs 0.37±0.08; p> 0.05) (Fig 3A and 3B). The CV of infarct volumes was 21.7% (0.08 of 0.37) on T2WI and 27.8% (0.10 of 0.35) on TTC, suggesting a high reproducibility of this model. The rVL in the MCAO group on T2WI at 24 hours was 0.34±0.24, and the CV of infarct volumes was 70% (0.24 of 0.34) (S1 Fig). Nissl-staining was further used to examine the neurons. The nuclei of neurons in the lesions appeared karyolytic and pyknotic, indicating a regional loss of pigmentation and tissue structure (Fig 3C). Histological abnormalities were not detected microscopically around the lesions or in the contralateral hemisphere (Fig 3D).

Bottom Line: One hour after occlusion, the low perfusion areas on the perfusion-weighted imaging interlaced with the hypointense areas on the apparent diffusion coefficient map, demonstrating that the penumbra was located both surrounding and inside the lesions.This phenomenon was subsequently confirmed by the c-fos and heart shock protein 90 staining.At early stages, the lesions were clearly identified on the apparent diffusion coefficient map; the volumes of the lesions on the diffusion-weighted imaging and T2-weighted imaging did not reach a maximum until 12 hours.

View Article: PubMed Central - PubMed

Affiliation: Jiangsu Key Laboratory of Molecular and Functional Imaging, Department of Radiology, Zhongda Hospital, Medical School, Southeast University, Nanjing, China.

ABSTRACT

Aims: To precisely characterize the penumbra by MRI based on a modified photothrombotic stroke mouse model.

Methods: The proximal middle cerebral artery was occluded by a convenient laser system in conjunction with an intravenous injection of Rose Bengal in mice. And the suture MCAO model was performed in seven mice as a comparison of the reproducibility. One hour after occlusion, the penumbra was defined in six random photothrombotic stroke mice by mismatch between perfusion-weighted imaging and the apparent diffusion coefficient map on a home-made workstation. After imaging, three random mice of them were chosen to perform the reperfusion surgery. And the other three mice were sacrificed to stain for several potential penumbra markers, such as c-fos and heart shock protein 90. In the remaining mice, the evolution of the lesions was detected on the apparent diffusion coefficient map, diffusion-weighted imaging and T2-weighted imaging at 1, 3, 6, 12 and 24 hours. After evaluating the neurological deficit scores, the brains were sectioned and stained by triphenyltetrazolium chloride and Nissl.

Results: The mice subjected to photothrombosis showed significant behavioral deficits. One hour after occlusion, the low perfusion areas on the perfusion-weighted imaging interlaced with the hypointense areas on the apparent diffusion coefficient map, demonstrating that the penumbra was located both surrounding and inside the lesions. This phenomenon was subsequently confirmed by the c-fos and heart shock protein 90 staining. The final T2-weighted images of the mice subjected to the reperfusion surgery were also consistent with the penumbra images at one hour. At early stages, the lesions were clearly identified on the apparent diffusion coefficient map; the volumes of the lesions on the diffusion-weighted imaging and T2-weighted imaging did not reach a maximum until 12 hours. The coefficient of variation (CV) of the final lesions in the photothrombotic stroke mice was 21.7% (0.08 of 0.37) on T2-weighted imaging and 27.8% (0.10 of 0.35) on triphenyltetrazolium chloride, representing a high reproducibility (n = 7). While the CV of the lesions in the MCAO stroke mice was only 70% (0.24 of 0.34, n = 4).

Conclusions: This study has provided a precise imaging definition of the penumbra based on a reproducible photothrombotic stroke mouse model.

No MeSH data available.


Related in: MedlinePlus