碘缺乏对子代大鼠不同脑区一氧化氮含量的影响

EFFECT OF IODINE DEFICIENCY AND HYPOTHYROIDISM ON NO CONTENTS IN DEFFERENT PARTS OF BRAIN IN RATS

目的 : 研究胚胎期和新生期碘缺乏、甲状腺功能低下对大鼠不同脑区 (海马、小脑、大脑皮质 )一氧化氮 (NO)含量的影响。方法 : 复制缺碘大鼠动物模型 ,取子代第 2、3胎大鼠各2 4只分别测定大脑匀浆蛋白质和 NO含量。结果 : 胚胎期和新生期碘缺乏、甲状腺功能低下的子鼠尿碘含量、血清 T3 、T4 含量都较正常对照组明显为低 (P<0 .0 1 ) ,有明显的生长发育障碍 (P<0 .0 1 ) ,学习记忆低下 (P<0 .0 1 )。 子鼠脑 NO含量的测定表明 ,海马 NO含量较正常对照组明显降低 ,差异有显著意义 (1 1 .6 1±2 .3 1 /2 .3 6± 1 .1 8μmol/g prot,P<0 .0 5 )。小脑 NO含量也明显降低 (1 0 .77± 5 .1 6 /4 .70± 1 .95μmol/g Prot,P<0 .0 5 )。大脑皮质 NO含量与对照组比较无明显差异。结论 : 胚胎期和新生期碘缺乏、甲状腺功能低下对子鼠脑组织 NO含量有影响。大脑不同区域对碘缺乏、甲状腺功能低下所致损伤敏感程度不同 ,海马内与 NO有关的代谢异常最明显 ,这一变化可能参与了碘缺乏大鼠学习记忆低下的发病机制。

Objective: This experiment was designed to study the change of nitric oxide (NO) content in different parts of brain in rats suffering from iodine deficiency(ID) and hypothyroidism since their fetal period. Methods: Iodine deficiency animal model was made and NO content in hippocampus(HPC), cerebellum (CE) and cortex(CO) were measured by using NO test kit. Results: Urinary iodine and serum T 3?T 4 concentrations significantly decreased and learning-memory capacity was impaired in ID rats. NO content was significantly lower in HPC and CE in ID rats than in control rats.(HPC:11.61±2.31/2.3±1 18 μmol/g Prot;CE:10.77±5.16/4.70±1.95 μmol/g Prot).No difference was found in cortex. Conclusion: Iodine deficiency and hypothyroidism since fetal period could affect NO level in rat brain. Different parts of brain have different sensitivity to ID and hypothyroidism.The changes of NO content in hippocampus may contribute to the learning-memory impairment in ID rats.