【摘要】 目的有研究表明甲状腺功能减退大鼠学习、记忆功能的损伤与神经元局部三碘甲状腺原氨酸(triiodothyronine,T3)缺乏有关。该研究探讨左旋三碘甲状腺原氨酸(L-T3)对新生小鼠兴奋毒性脑损伤后学习、记忆行为的影响。方法5日龄ICR种小鼠71只,用鹅膏蕈氨酸(ibotenicacid,IA)建立兴奋毒性脑损伤模型,随机分为磷酸盐缓冲液(PBS)组(n=14,脑内及腹腔注射PBS10mL/kg)、IA组(n=14,脑内注射IA+腹腔注射PBS10mL/kg)、低剂量T3组(n=14,脑内注射IA+腹腔注射L-T30.2μg/kg)、中剂量T3组(n=15,脑内注射IA+腹腔注射L-T30.5μg/kg)、高剂量T3组(n=14,脑内注射IA+腹腔注射L-T31μg/kg)。腹腔注射时间为小鼠脑内注射后1、24、48、72、96h。小鼠于生后第33、34天进行Y-迷宫分辨学习实验。结果PBS组、IA组、低、中、高剂量L-T3组小鼠学会所需次数分别为15.0±4.7、21.3±6.3、20.5±6.0、21.0±6.5、15.8±4.5,高剂量L-T3组小鼠"学会"所需次数明显低于IA组和中、低剂量L-T3组(P<0.05);记忆正确率分别为(90.7±7.3)%、(79.3±10.0)%、(77.9±14.2)%、(80.7±12.2)%、(91.4±9.5)%,高剂量L-T3组小鼠记忆正确率明显高于IA组和中、低剂量L-T3(P<0.05)。结论高剂量L-T3(1μg/kg)能促进兴奋毒性脑损伤小鼠的学习记忆行为。更多还原

【Abstract】 Objective Some research has shown that learning and memory function impairments in rats with hypothyroidism are associated with triiodothyronine (T3) deficiency in neurons.This study aimed to investigate the effects of L-T3 administration on learning and memory behaviors in neonatal mice with excitotoxic brain damage.Methods Seventy-one 5-day-old ICR neonatal mice were randomly assigned to five groups:controls that received intracerebral and intraperitoneal injections of phosphate buffered saline (PBS) (n=14);a group that received intracerebral injections of ibotenic acid (IA) and intraperitoneal injection of PBS (n=14);3 groups that received intracerebral injections of IA and intraperitoneal injection of L-T3 at 0.2,0.5,and 1 μg/kg,respectively (n=14-15).Intraperitoneal injections were done 1,24,48,72 and 96 hrs after intracerebral injections.Learning and memory functions were evaluated by the Y-maze discrimination learning test on postnatal days 33-34.Results The learning and memory functions in the highest L-T3 dose group were significantly better than those in the IA,and the lower L-T3 dose groups,presenting with decreased number of trials to criterion [15.8±4.5 vs 21.3±6.3 (IA group),20.5±6.0 (0.2 μg/kg L-T3 group) or 21.0±6.5 (0.5 μg/kg L-T3 group);P<0.05],and achieving a higher correct percentage [91.4±9.5% vs 79.3±10.0% (IA group),77.9±14.2% (0.2 μg/kg L-T3 group) or 80.7±12.2% (0.5 μg/kg L-T3 group);P<0.05].Conclusions High-dose L-T3 (1 μg/kg) may improve learning and memory functions in mice following excitotoxic brain damage.更多还原