长期注射叠氮钠对大鼠学习记忆和海马内褪黑素受体表达的作用

Effects of sodium azide injected chronically on the learning and memory and the expression of melatonin receptors in the hippocampus of rats

目的 观察长期皮下注射叠氮钠所致的AD大鼠氧化应激模型学习记忆和海马内褪黑素受体表达的变化。方法 采用Morris水迷宫检测大鼠的学习记忆。原位杂交技术检测大鼠海马内褪黑素受体Mel 1a和Mel 1b的表达。结果 皮下间断注射NaN3后 1～ 4周 ,大鼠Morris水迷宫测试潜伏期延长 ,以注射叠氮钠 4周组大鼠的潜伏期升高最为明显。大鼠海马Mel 1a受体表达在注射叠氮钠后 1周上调 ,在 2周和 3周组仍过度表达 ,在 4周组达峰值。而Mel 1b受体表达无明显变化。结论 大鼠长期皮下注射叠氮钠导致学习记忆障碍 ,可作为AD模型。AD大鼠海马内褪黑素受体Mel 1a的过表达可能是对MT水平下降和氧化应激的代偿反应。

Objective To observe the effects of sodium azide injected chronically on the learning and memory and the expression of melatonin receptors in the hippocampus of Alzheimer disease oxidative stress rats. Methods The learning and memory of rats were tested by Morris water maze. The expressions of melatonin receptors Mel 1a and Mel 1b were detected by in situ hybridization. Results The escape latency of the rats increased significantly after chronically subcutaneousy injection of sodium azide and significantly increase was found in group of 4 weeks of injection. The melatonin receptor Mel 1a was overexpressed 1 week after injection of sodium azide, remaining at high level 2 and 3 weeks later and peaking 4 weeks later. No significant change of the expression of Mel 1b was found. Conclusion Learning and memory retention disorders of the rats due to chronically subcutaneous injection of sodium azide can be used as AD model. The overexpression of Mel 1a melatonin receptor in the hippocampus of AD rats may probably be the compensation response to the decrease of melatonin level and oxidative stress.