Objective:To observe the learning and memory ability of young rat from pregnant rat of hypothyroidism and expression of hippocampal reelin protein.Methods:The pregnant mice with successful mating were randomly divided into control group,hypothyroidism group and treatment group,with 15 rats in each group.On the sixth day of pregnancy (GD6) ～ GD14,pregnant rats of hypothyroidism group and treatment group were treated with tap water of 20 mg/L propylthiouracil (PTU) to establish hypothyroidism model in pregnancy until the baby mouse was born.The treatment group was subcutaneously injected with levothyroxine 0.02 μg/g at GD15.All rats were fed normally for seventh days (PN7) after birth,and 30 rats were kept in each group.The weight of all GD6,GD15 pregnant rats and PN0 weight of offspring rats were measured,and the serum of total thyroxine (TT4) and the value of thyroid stimulating hormone (TSH) were measured in 5 pregnant rats of each group at GD15.15 PN7 rats of each group were selected for Morris water maze positioning navigation and space exploration experiment to test the learning and memory ability of offspring rats,and the expression of Reelin protein in hippocampus was detected by immunohistochemistry in 15 rats of each group.Results:Pregnant mice TT4 of hypothyroidism group and the treatment group was significantly lower than the control group,and TSH was significantly higher than the control group,suggesting hypothyroidism successfully modeling during pregnancy.At GD15,the weight of pregnant rats in the hypothyroidism group and treatment group was significantly lower than that in the control group (P ＜ 0.05),and the weight of the young rats in the hypothyroidism group and treatment group was significantly lower than that in the control group at PN0 (P ＜ 0.05).On the same day,the latency of hypothyroidism group was significantly longer than that of the treatment group in positioning navigation experiment of offspring rats (P ＜ 0.05),and the number of crossing the platform in hypothyroidism group was significantly less than that of the treatment group (P ＜ 0.05).The expression of Reelin protein in PN7 rats of hypothyroidism group was significantly lower than that of control group and treatment group,and the difference was statistically significant (P ＜ 0.05).Conclusion:Hypothyroidism during pregnancy affects the learning and memory ability of offspring,and its mechanism may be associated with hypothyroidism during pregnancy and reduce the expression of Reelin protein in hippocampus of offspring rats.%目的:观察甲状腺功能减退(甲减)孕鼠的仔鼠学习记忆能力及海马Reelin蛋白表达.方法:选取交配成功孕鼠随机分为对照组、甲减组、治疗组,各15只;甲减组和治疗组孕鼠于妊娠第6天(GD6)～GD14时给予含有20 mg/L丙基硫氧嘧啶(PTU)的自来水建立妊娠期甲减模型至仔鼠出生;治疗组在GD15时,皮下注射注射左旋甲状腺激素0.02μg/g;对照组孕鼠喂养正常食物和自来水;所有仔鼠出生后正常喂养至第7天(PN7),每组保留仔鼠30只;分别测量所有GD6、GD15孕鼠体质量和仔鼠PN0体质量,GD15时每组取5只孕鼠测定血清总甲状腺素(TT4)和促甲状腺激素(TSH)值;每组选取15只PN7仔鼠进行Morris水迷宫定位航行和空间探索实验测试仔鼠学习记忆能力,每组15只仔鼠采用免疫组化方法检测海马组织Reelin蛋白的表达情况.结果:甲减组、治疗组孕鼠TT4明显低于对照组,TSH明显高于对照组,提示妊娠期甲减造模成功;GD15时甲减组、治疗组孕鼠体质量明显低于对照组(P＜0.05),PN0时甲减组、治疗组仔鼠体质量明显低于对照组(P＜0.05);仔鼠定位航行实验,同一天甲减组潜伏期明显长于治疗组(P＜0.05),甲减组穿越站台次数明显少于治疗组(P＜0.05);甲减组PN7仔鼠Reelin蛋白表达明显低于对照组和治疗组,差异有统计学意义(P＜0.05).结论:妊娠期甲减影响子代学习记忆能力,其机制可能与妊娠期甲减可降低仔鼠海马Reelin蛋白表达.
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