Glial cell line-derived neurotropic factor and postoperative cognitive impairment in young rats

在美国，每年有数百万儿童接受麻醉和手术。 表明麻醉和手术会导致发育中的大脑认知障碍。这 这一发现引起了极大的关注。能够识别可能有发展风险的儿童， 认知功能障碍，并提供干预那些选择性的儿童，有必要有 手术引起的认知功能障碍的生物标志物。我们的初步研究表明， 出生后7天（P7）大鼠的学习和记忆能力受损。手术也减少了神经胶质细胞系- 衍生的神经营养因子（GDNF）在大脑和尿液中。侧脑室注射GDNF 减轻手术引起的学习和记忆障碍。侧脑室注射 抗GDNF抗体可使对照组大鼠的学习记忆功能受损。由于神经炎症是一种 手术诱导的成人认知功能障碍的早期神经病理过程，神经发生和 树突状分支对于学习和记忆是重要的，GDNF抑制神经炎症 并增强神经发生和树突分支，我们假设手术减少了GDNF， 从而加剧神经炎症并减少神经发生和树突分支， 诱导学习和记忆障碍和尿中GDNF减少是 麻醉和手术引起的学习和记忆障碍。在这个项目中，我们将确定 是否：1）麻醉和手术减少年轻大鼠中包括GDNF在内的生长因子; 2）减少 尿中GDNF的含量预测手术后学习和记忆障碍; 3）GDNF减少 导致神经炎症加剧，神经发生和树突发育受损， 大脑P7大鼠将在七氟烷下进行右颈动脉探查或剖腹手术 麻醉将通过巴恩斯迷宫和恐惧条件反射评价学习和记忆。大脑会 收获用于生化检查和脑细胞发生和树突状细胞的测定 树枝化将定量尿液GDNF水平。受试者工作特征（ROC）曲线将 构建以评估使用尿GDNF水平作为手术诱导的肿瘤的生物标志物的价值。 学习和记忆障碍这些研究将确定可能的生物标志物， 新生大鼠学习记忆障碍。他们还将揭示GDNF对 神经炎症和手术后发育中大脑的长期大脑结构变化。

Millions of children each year undergo anesthesia and surgery in the U.S.A. Recent studies suggest that anesthesia and surgery can cause cognitive impairment in the developing brain. This finding causes significant concern. To be able to identify children that may be at risk for developing cognitive dysfunction and to provide intervention to those selective children, it is necessary to have biomarkers for surgery-induced cognitive dysfunction. Our preliminary study showed that surgery on postnatal day 7 (P7) rats impaired their learning and memory. Surgery also decreased glial cell line- derived neurotropic factor (GDNF) in the brain and urine. Intracerebroventricular injection of GDNF attenuated surgery-induced learning and memory impairment. Intracerebroventricular injection of an anti-GDNF antibody impaired the learning and memory of control rats. Since neuroinflammation is an early neuropathological process for surgery-induced cognitive dysfunction in adults, neurogenesis and dendritic arborization are important for learning and memory, and GDNF inhibits neuroinflammation and enhances neurogenesis and dendritic arborization, we hypothesize that surgery reduces GDNF, which then heightens neuroinflammation and decreases neurogenesis and dendritic arborization, to induce learning and memory impairment and that reduction of GDNF in the urine is a biomarker for anesthesia and surgery-induced learning and memory impairment. In this project, we will determine whether: 1) anesthesia and surgery reduce growth factors including GDNF in young rats; 2) decrease of GDNF in the urine predicts learning and memory impairment after surgery; and 3) GDNF decrease leads to heightened neuroinflammation and impairment of neurogenesis and dendritic development in the brain. P7 rats will be subjected to right carotid arterial exploration or laparotomy under sevoflurane anesthesia. Learning and memory will be evaluated by Barnes maze and fear conditioning. Brains will be harvested for biochemical examination and determination of brain cell genesis and dendritic arborization. Urine GDNF levels will be quantified. Receiver operating characteristic (ROC) curves will be constructed to assess the value of using urine GDNF levels as a biomarker for surgery-induced learning and memory impairment. These studies will identify possible biomarkers for surgery-induced learning and memory impairment in the neonatal rats. They will also reveal the effects of GDNF on neuroinflammation and the long-term brain structural changes in developing brain after surgery.