关键词: 左旋甲状腺素, 亚临床甲减, 仔鼠

Abstract: Objective To investigate the optimal timing of L-thyroxine ( L-T4 ) treatment for subclinical hypothyroidism ( SCH ) in rats during pregnancy. Method One hundred and fifty SPF Wistar female rats were randomly divided into 6 groups in accordance with the random number table, each with 25 cases, namely, control group, SCH group, hypothyroidism ( CH) group, group A, group B and group C. Enzyme-linked immunosorbent assay was used to determine the levels of serum thyroid-stimulating hormone ( TSH ) and total thyroxine ( TT4) in pregnant rats. The Morris water maze test was used to detect the learning and memory ability of rats offspring. Then the optimal timing of the treatment was analyzed. Result At P3 , P7 and P40, the weight of offspring of CH group was lower than that of the control group ( P<0.05). At P3 , the weight of offspring was higher in the SCH group than in the CH group ( P<0. 05 ) . At P7, the weight of offspring of CH group was lower than that of the group A and group B ( P<0. 05 ) . And the weight of offspring of CH group was lower than that of the group B and group C at P40 ( P<0. 05 ) . Compared with other groups, the control group had a significant decrease in the escape latency, which is steady and progressive. The distribution of the cortical and hippocampal nerve cells were disordered with unclear boundaries. Conclusion The established model rats reveal that the offspring of the SCH rats have abnormal weight and weakened learning and memory ability, while the conditions can be ameliorated by the L-T4 treatment before E13.

Key words: L-thyroxine , SCH , rats offspring