Hospital Israelita Albert Einstein, São Paulo, Brazil.
Santa Casa Misericórdia de São Paulo, São Paulo, Brazil.
PLoS One. 2018 Jul 5;13(7):e0200135. doi: 10.1371/journal.pone.0200135. eCollection 2018.
The thermocoagulation model, which consists of focal cerebral ischemia with craniectomy, is helpful in studying permanent ischemic brain lesions and has good reproducibility and low mortality. This study analyzed the best conditions for inducing a focal ischemic lesion by thermocoagulation. We investigated parameters such as temperature and thermal dissipation in the brain tissue during induction and analyzed real-time blood perfusion, histological changes, magnetic resonance imaging (MRI), and motor behavior in a permanent ischemic stroke model. We used three-month-old male Wistar rats, weighing 300-350 g. In the first experiment, the animals were divided into four groups (n = 5 each): one sham surgery group and three ischemic lesion groups having thermocoagulation induction (TCI) temperatures of 200°C, 300°C, and 400°C, respectively, with blood perfusion (basal and 30 min after TCI) and 2,3,5-Triphenyl-tetrazolium chloride (TTC) evaluation at 2 h after TCI. In the second experiment, five groups (n = 5 each) were analyzed by MRI (basal and 24 h after TCI) and behavioral tests (basal and seven days after TCI) with the control group added for the surgical effects. The MRI and TTC analyses revealed that ischemic brain lesions expressively evolved, especially at TCI temperatures of 300°C and 400°C, and significant motor deficits were observed as the animals showed a decrease frequency of movement and an asymmetric pattern. We conclude that a TCI temperature of 400°C causes permanent ischemic stroke and motor deficit.
热凝模型包括开颅去骨的局灶性脑缺血，有助于研究永久性缺血性脑损伤，具有良好的重现性和低死亡率。本研究分析了通过热凝诱导局灶性缺血性损伤的最佳条件。我们研究了诱导过程中脑组织中的温度和热耗散等参数，并分析了永久性缺血性中风模型中的实时血流灌注、组织学变化、磁共振成像（MRI）和运动行为。我们使用了 3 个月大、体重 300-350 克的雄性 Wistar 大鼠。在第一个实验中，动物分为四组（每组 5 只）：一组假手术组和三组分别接受 200°C、300°C 和 400°C 热凝诱导的缺血性损伤组，分别在热凝诱导前（基础状态）和诱导后 30 分钟（TCI 后）以及 TCI 后 2 小时（TCI 后）进行血流灌注和 2,3,5-三苯基氯化四氮唑（TTC）评估。在第二个实验中，通过 MRI（TCI 前后基础状态和 24 小时）和行为测试（TCI 前后基础状态和 7 天）分析了五组（每组 5 只），增加了对照组以评估手术效果。MRI 和 TTC 分析表明，缺血性脑损伤明显发展，尤其是在 TCI 温度为 300°C 和 400°C 时，动物表现出运动频率降低和不对称模式，表明存在明显的运动缺陷。我们得出结论，TCI 温度为 400°C 会导致永久性缺血性中风和运动缺陷。
