Consistent focal cerebral ischemia without posterior cerebral artery occlusion and its real-time monitoring in an intraluminal suture model in mice

Laboratory investigation

Restricted access

Object

In the intraluminal suture model of middle cerebral artery occlusion (MCAO) in the mouse, disturbance of blood flow from the internal carotid artery to the posterior cerebral artery (PCA) may affect the size of the infarction. In this study, PCA involvement in the model was investigated and modified for consistent MCAO without involving the PCA territory.

Methods

Thirty-seven C57Bl/6 mice were randomly divided into 4 groups according to the length of coating over the tip of the suture (1, 2, 3, or 4 mm) and subjected to transient MCAO for 2 hours. Real-time topographical cerebral blood flow was monitored over both hemispheres by laser speckle flowmetry. After 24 hours of reperfusion, the infarct territories and volumes were evaluated.

Results

The 1- and 2-mm coating groups showed all lesions in the MCA territory. In the 3- and 4-mm coating groups, 62.5% and 75% of mice, respectively, showed lesions in both the MCA and the PCA territories and other lesions in the MCA territory. Mice in the 1- and 2-mm coating groups had significantly smaller infarct volumes than the 3- and 4-mm groups. Laser speckle flowmetry was useful to distinguish whether the PCA territory would undergo infarction.

Conclusions

Small changes in the coating length of the intraluminal suture may be critical, and 1–2 mm of coating appeared to be optimal to produce consistent MCAO without involving the PCA territory. Laser speckle flowmetry could predict the territory of infarction and improve the consistency of the infarct size.

Abbreviations used in this paper: ACA = anterior cerebral artery; CBF = cerebral blood flow; CCA = common carotid artery; ECA = external carotid artery; ICA = internal carotid artery; LSF = laser speckle flowmetry; MCA = middle cerebral artery; MCAO = MCA occlusion; PCA = posterior cerebral artery; PCAO = PCA occlusion; PCoA = posterior communicating artery; ROI = region of interest; SCA = superior cerebellar artery; TTC = 2,3,5-triphenyltetrazolium chloride.

Article Information

Address correspondence to: Yosuke Akamatsu, M.D., Department of Neurosurgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan. email: redpine7219@hotmail.co.jp.

Please include this information when citing this paper: published online December 23, 2011; DOI: 10.3171/2011.11.JNS111167.

© AANS, except where prohibited by US copyright law.

Headings

Figures

  • View in gallery

    A: Photograph showing intraluminal silicone-coated 7-0 monofilament sutures. The lengths of the coating on the tips are 4 mm (upper) and 2 mm (lower) (grid width = 1 mm). B: Photograph showing the base of the brain and the circle of Willis after transcardial injection of carbon black gelatin into the cerebral arteries. The intraluminal suture with 2 mm of coating (arrows) was left in situ, occluding the left ICA and ACA to block the origins of the MCA. The PCA (arrowheads) was filled with carbon black gelatin, indicating that the origin of the PCA was not occluded and received blood flow from the ICA with this type of suture. C: Representative TTC-stained serial coronal sections (2 mm thick) showing infarction only in the MCA territory (MCAO) (upper row) and involving the MCA and PCA territories (MCAO + PCAO) (lower row). D: Graph comparing the 4 groups and infarct territory. Two and 3 mice in Groups 3 and 4, respectively, died before 24 hours of reperfusion and were not included in this analysis. In Groups 1 and 2, the lesions occurred only in the MCA territory. Five of 8 mice in Group 3 and 6 of 8 mice in Group 4 demonstrated lesions involving the MCA and PCA territories. E: Box plot. In the graph, the horizontal line indicates the median, the box indicates the lower and upper quartiles, and the whiskers indicate the range. The mean infarct volume of Group 1 (37.8 ± 6.5 mm3) was significantly smaller than that of Group 3 (63.1 ± 18.0 mm3) (p < 0.01) and Group 4 (72.1 ± 16.9 mm3) (p < 0.001). The mean infarct volume of Group 2 (43.8 ± 6.9 mm3) was significantly smaller than that of Group 3 (p < 0.05) and Group 4 (p < 0.001). Note that standard deviations of Groups 1 and 2 are smaller than those of Groups 3 and 4.

  • View in gallery

    A: Photograph obtained after removal of the scalp, showing the normal mouse brain (bilateral cerebral cortices) covered with the skull, which is thin and transparent. The arrow indicates the midline. Ant = anterior. B: Pseudocolor image showing CBF obtained from the same mouse as in panel A by LSF using the 64-level color scale depicted on the bottom (arbitrary unit). C: Photograph of the normal mouse brain (bilateral cerebral cortices) showing the representative distribution of cerebral arteries after transcardial perfusion and staining with carbon black gelatin. Territories supplied by the MCA, PCA, and ACA can be distinguished clearly. D and E: Representative pseudocolor images of CBF obtained during ischemia, showing flow reduction only in the MCA territory (D) or in both the MCA and the PCA territories (E).

  • View in gallery

    Box plots. In all graphs, the horizontal line indicates the median, the box indicates the lower and upper quartiles, and the whiskers indicate the range. A and B: Graph showing the %CBF in the MCA (A) and PCA (B) territories. The %CBF value of the ipsilateral MCA territory was approximately 60% of that of the contralateral MCA territory. The %CBF in Group 1 (56.2% ± 3.6%) was significantly higher than that of Group 4 (45.8% ± 8.8%) (p < 0.05). However, the %CBF of the PCA territory was more variable within and between groups. Group 1 (83.0% ± 11.1%) and Group 2 (78.7% ± 9.8%) demonstrated no histologically detectable infarction as evaluated by TTC staining in the ipsilateral PCA territory. In Group 3, 5 of 8 mice demonstrated infarction on TTC staining in the PCA territory, but the mean %CBF (68.8% ± 15.3%) was not significantly different from that of Group 1 or 2. In Group 4, 6 of 8 mice demonstrated infarction in the PCA territory, and the mean %CBF (57.6% ± 19.0%) was significantly different from that of Groups 1 and 2 (p < 0.01 and p < 0.05, respectively). C and D: Graph showing the %CBF of the MCA (C) and PCA (D) territories in the MCAO and MCAO + PCAO groups. The MCAO group consisted of 21 animals that demonstrated infarction only in the MCA territory on TTC staining (8 in Group 1, 8 in Group 2, 3 in Group 3, and 2 in Group 4). The MCAO + PCAO group consisted of 11 animals that demonstrated infarction in both the MCA and the PCA territories (5 in Group 3 and 6 in Group 4). The %CBF in the MCA territory was around 50% in both groups and was lower in the MCAO + PCAO group (46.8% ± 8.3%) than in the MCAO group (51.6% ± 6.8%), although the difference was not significant (p = 0.08). In contrast, the %CBF in the PCA territory remained at 81.4% ± 10.2% in the MCAO group, which was significantly higher than 54.1% ± 10.7% in the MCAO + PCAO group (p < 0.001).

  • View in gallery

    Graph showing the correlation between infarct volume and patency of the PCoA (PcomA) in Group 4. The patency of the ipsilateral PCoA was graded under microscopic observation after transcardial injection of carbon black gelatin 24 hours after reperfusion. See Evaluation of the PCoA on the Ischemic Side for an explanation of the scoring system. The infarct volume increased as the patency of the PCoA decreased from Grade 3 to Grade 0.

  • View in gallery

    Graphs showing the degree of neurological deficits assessed at 24 hours after reperfusion by the 4-point neurological severity scale. A: Groups 3 and 4 (scores of 3.1 ± 1.1 and 2.8 ± 0.7, respectively) tended to show more severe neurological deficits than Groups 1 and 2 (scores of 2.1 ± 0.8 and 2.3 ± 0.9, respectively), but the difference between the 4 groups was not statistically significant. B: The mean neurological score of combined Groups 3 and 4 (score of 2.9 ± 0.9) was significantly higher than that of combined Groups 1 and 2 (score of 2.2 ± 0.8) (p = 0.02). C: Similarly, the mean neurological scores of the MCAO + PCAO group with infarction in both the MCA and the PCA territories (3.4 ± 0.3) were significantly higher than those of the MCAO group with infarction only in the MCA territory (2.2 ± 0.2) (p = 0.002).

References

  • 1

    Ayata CDunn AKGursoy-OZdemir YHuang ZBoas DAMoskowitz MA: Laser speckle flowmetry for the study of cerebrovascular physiology in normal and ischemic mouse cortex. J Cereb Blood Flow Metab 24:7447552004

  • 2

    Barber PAHoyte LColbourne FBuchan AM: Temperature-regulated model of focal ischemia in the mouse: a study with histopathological and behavioral outcomes. Stroke 35:172017252004

  • 3

    Belayev LBusto RZhao WFernandez GGinsberg MD: Middle cerebral artery occlusion in the mouse by intraluminal suture coated with poly-L-lysine: neurological and histological validation. Brain Res 833:1811901999

  • 4

    Chen YIto ATakai KSaito N: Blocking pterygopalatine arterial blood flow decreases infarct volume variability in a mouse model of intraluminal suture middle cerebral artery occlusion. J Neurosci Methods 174:18242008

  • 5

    Clark WMLessov NSDixon MPEckenstein F: Monofilament intraluminal middle cerebral artery occlusion in the mouse. Neurol Res 19:6416481997

  • 6

    Connolly ES JrWinfree CJStern DMSolomon RAPinsky DJ: Procedural and strain-related variables significantly affect outcome in a murine model of focal cerebral ischemia. Neurosurgery 38:5235321996

  • 7

    Forrester KRStewart CTulip JLeonard CBray RC: Comparison of laser speckle and laser Doppler perfusion imaging: measurement in human skin and rabbit articular tissue. Med Biol Eng Comput 40:6876972002

  • 8

    Fujii MHara HMeng WVonsattel JPHuang ZMoskowitz MA: Strain-related differences in susceptibility to transient forebrain ischemia in SV-129 and C57black/6 mice. Stroke 28:180518111997

  • 9

    Kidoguchi KTamaki MMizobe TKoyama JKondoh TKohmura E: In vivo X-ray angiography in the mouse brain using synchrotron radiation. Stroke 37:185618612006

  • 10

    Kitagawa KMatsumoto MYang GMabuchi TYagita YHori M: Cerebral ischemia after bilateral carotid artery occlusion and intraluminal suture occlusion in mice: evaluation of the patency of the posterior communicating artery. J Cereb Blood Flow Metab 18:5705791998

  • 11

    Koizumi JYoshida YNakazawa TOoneda G: Experimental studies of ischemic brain edema, I: a new experimental model of cerebral embolism in rats in which recirculation can be introduced in the ischemic area. Jpn J Stroke 8:181986

  • 12

    Leach MJSwan JHEisenthal DDopson MNobbs M: BW619C89, a glutamate release inhibitor, protects against focal cerebral ischemic damage. Stroke 24:106310671993

  • 13

    Liu SLiu WDing WMiyake MRosenberg GALiu KJ: Electron paramagnetic resonance-guided normobaric hyperoxia treatment protects the brain by maintaining penumbral oxygenation in a rat model of transient focal cerebral ischemia. J Cereb Blood Flow Metab 26:127412842006

  • 14

    Longa EZWeinstein PRCarlson SCummins R: Reversible middle cerebral artery occlusion without craniectomy in rats. Stroke 20:84911989

  • 15

    Maeda KHata RHossmann KA: Differences in the cerebrovascular anatomy of C57black/6 and SV129 mice. Neuroreport 9:131713191998

  • 16

    Majid AHe YYGidday JMKaplan SSGonzales ERPark TS: Differences in vulnerability to permanent focal cerebral ischemia among 3 common mouse strains. Stroke 31:270727142000

  • 17

    Murakami KKondo TKawase MChan PH: The development of a new mouse model of global ischemia: focus on the relationships between ischemia duration, anesthesia, cerebral vasculature, and neuronal injury following global ischemia in mice. Brain Res 780:3043101998

  • 18

    Schmid-Elsaesser RZausinger SHungerhuber EBaethmann AReulen HJ: A critical reevaluation of the intraluminal thread model of focal cerebral ischemia: evidence of inadvertent premature reperfusion and subarachnoid hemorrhage in rats by laser-Doppler flowmetry. Stroke 29:216221701998

  • 19

    Tsuchiya DHong SKayama TPanter SSWeinstein PR: Effect of suture size and carotid clip application upon blood flow and infarct volume after permanent and temporary middle cerebral artery occlusion in mice. Brain Res 970:1311392003

  • 20

    Türeyen KVemuganti RSailor KADempsey RJ: Ideal suture diameter is critical for consistent middle cerebral artery occlusion in mice. Neurosurgery 56:1 Suppl1962002005

  • 21

    Yang GKitagawa KMatsushita KMabuchi TYagita YYanagihara T: C57BL/6 strain is most susceptible to cerebral ischemia following bilateral common carotid occlusion among seven mouse strains: selective neuronal death in the murine transient forebrain ischemia. Brain Res 752:2092181997

TrendMD

Metrics

Metrics

All Time Past Year Past 30 Days
Abstract Views 138 138 11
Full Text Views 185 185 5
PDF Downloads 139 139 4
EPUB Downloads 0 0 0

PubMed

Google Scholar