A stable focal cerebral ischemia injury model in adult mice: assessment using 7T MR imaging.

BACKGROUND AND PURPOSE A stable stroke experimental model is highly desirable for performing longitudinal studies using MR imaging. The purpose of this study is to establish a stable focal cerebral ischemia model with a high survival rate in adult mice. MATERIALS AND METHODS One hundred twenty adult mice were randomly divided into 10 groups of 12 each to respectively undergo intraluminal suture occlusion, with suture insertion depths from 0.8 cm to maximum; thromboembolic occlusion; and hypoxic-ischemic injury with hypoxia exposure times from 30-120 minutes. Coronal brain T2-weighted images were obtained on a 7T scanner. The induced infarct volume and location were assessed and correlated with histologic TTC staining. One-day and 7-day survival rates were recorded. RESULTS The infarct location was highly variable in the thromboembolic model, while it showed a cortex predominance in the intraluminal model with the suture insertion depth ≥1.4 cm, and the HI model with hypoxia exposure times ≥60 minutes (P = .001). The infarct volume in the intraluminal model with suture depths ≥1.4 cm (29.7 ± 3.3%, 35.4 ± 4.3%) and the HI model with the hypoxia exposure times ≥90 minutes (26.3 ± 4.1%, 33.4 ± 2.8%) were larger than other groups (9.7 ± 3.3%-20.9 ± 9.3%; P < .05). The HI group (72.5%) had higher 7-day survival rate than the intraluminal suture occlusion (28%) and thromboembolic occlusion groups (20%; P = .001). CONCLUSIONS The HI injury model with a reproducible ishemia and high survival rate can be used for a longitudinal study of brain ischemia in adult mice.