Objective To observe the impact of various suture insertion depths on the survival rate and brain changes of intraluminal suture middle cerebral artery occlusion (MCAO) models using MRI. Methods Forty adult SD rats were randomly divided into 4 groups (each n=10), and intraluminal MCAO modeling was performed respectively with the suture insertion depth of 1. 8 cm, 2. 0 cm, 2. 2 cm and maximum (until no longer advanceable, about 2. 4-2. 5 cm). Brain MR imaging and TTC staining were performed, and the infarct volume and lesion distribution on MRI were assessed 48 h later, and the survival rate was recorded after 24 h and 48 h. Results When the suture insertion depth was 1. 8 cm, 2. 0 cm, 2. 2 cm and maximum, the infarct volume measured on MRI 48 h later was (8. 25 ± 3. 24)%, (16. 18 ± 3. 41)%, (21. 18 ± 3.61)% and (33. 87±3. 45) % , and the variation coefficient was 0.39, 0.21, 0.17 and 0.10, and the survival rate was 100% (10/10), 80.00% (8/10), 50.00% (5/10) and 30. 00% (3/10), respectively. In intramural model with the suture insertion depth 1. 8 cm, the modeling success rate was low, and the infarct volume was small 48 h later. In intramural model with the suture insertion depth 2. 0 and 2. 2 cm, the resulted infarct volume was larger, but the survival rate decreased with insertion depth 2. 2 cm (P<0. 05). In intramural model with maximum suture insertion depth, the resulted infarct volume was the largest and the survival rate was the lowest. The infarct location was not significantly different among different suture insertion depths (P>0. 05). Conclusion With the increase of suture insertion depth in MCAO mo-del, the resulted infarct volume will increase and animal survival rate will decrease. The infarction has a tendency of cortical involvement. The suture insertion depth of 2. 0 cm is suitable for establishing stable MCAO experimental models with high survival rate in adult rats.%目的 观察不同插线深度对线栓法成年大鼠大脑中动脉阻断(MCAO)模型的脑MRI及存活率的影响.方法 依据模型栓线插入深度,将40只成年SD大鼠分为4组,每组10只,分别插入栓线1.8 cm、2.0 cm、2.2 cm及最大深度(插入至遇到较大阻力,约2.4～2.5 cm)制作模型；48 h后行脑部MRI及TTC染色,测量MRI上的梗死体积及梗死部位分布,观察不同栓线深度模型24 h及48 h的存活率.结果 插入栓线1.8 cm、2.0 cm、2.2 cm及最大时,48 h后MRI显示脑梗死体积分别为(8.25±3.24)％、(16.18±3.41)％、(21.18±3.61)％和(33.87±3.45)％,其变异系数分别为0.39、0.21、0.17、0.10;48 h动物存活率分别为100％(10/10)、80.00％(8/10)、50.00％(5/10)及30.00％(3/10).栓线深度为1.8 cm时,造模后48 h,脑梗死体积相对较小,造模成功率较低；栓线深度为2.0 cm及2.2 cm时,脑梗死体积较大；但栓线深度为2.2 cn时动物存活率下降(P＜0.05)；栓线深度最大时,脑梗死体积最大,但存活率最低.不同栓线深度的脑梗死部位分布差异无统计学意义(P＞0.05).结论 线栓法MCAO模型中,栓线插入越深,脑梗死体积越大,动物存活率越低,越易累及皮层.深度2.0 cm更适用于建立梗死灶较稳定且动物存活率较高的实验性大鼠缺血脑损伤模型.
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