【摘要】 目的:探讨脑发育期甲状腺功能低下大鼠脑干听觉诱发电位(BAEP)的变化。方法:孕鼠从孕17 d至仔鼠生后30 d饮质量分数0.03%甲巯咪唑的自来水诱发脑发育期甲状腺功能低下仔鼠;甲低大鼠生后1~30 d每日腹腔注射左旋甲状腺素(20μg/kg)进行替代治疗;放射免疫法测定大鼠血清FT3和FT4;计算机平均叠加技术颅表记录大鼠BAEP,连续3个月动态观察甲低大鼠波峰潜伏期(PL)、波峰间潜伏期(IPL)和波幅的变化。结果:对照组大鼠生后20 d引出清晰的BAEP,甲低组大鼠生后20 d时未能引出BAEP,生后30、50、70和90 d BAEP各波PL均明显长于对照组(P<0.01);替代组大鼠生后20 d时能引出BAEP,除生后20 dⅣ波PL明显长于对照组、生后30 dⅠ波PL明显短于对照组和生后50 dⅢ、Ⅳ、Ⅴ波PL明显长于对照组外(P<0.01或P<0.05),生后20~90 d各波PL与对照组无显著差异;甲低组大鼠生后30、50、70和90 dⅠ-Ⅲ、Ⅲ-Ⅴ、Ⅰ-ⅤIPL均明显长于对照组(P<0.01或P<0.05);替代组大鼠除生后20 dⅠ-ⅢIPL和生后50dⅠ-Ⅲ、Ⅰ-ⅤIPL明显长于对照组外(P<0.01或P<0.05),生后20~90 dⅠ-Ⅲ、Ⅲ-Ⅴ、Ⅰ-ⅤIPL同对照组无显著差异;甲低组大鼠生后30、50、70和90 d BAEP各波波幅均明显低于对照组(P<0.01或P<0.05),替代组大鼠各年龄段BAEP各波波幅同对照组无显著差异。结论:脑发育期甲状腺功能低下大鼠BAEP的发育明显延缓,及早补充甲状腺素能显著改善其脑发育障碍。更多还原

【Abstract】 Aim: To study the changes of BAEP in the rats with hypothyroidism in the period of brain development.Methods: The rats with hypothyroidism in the period of brain development were induced by 0.03% methimazole added in drinking water for their mother rats from the pregnant day 17 to the postnatal day 30 of their rat pups.Injection of L-T₄(20 μg·kg^-1·d^-1) into abdominal cavity of the hypothyroidism rats from postnatal day 1 to 30 was used for replacement treatment.Serum FT₃ and FT₄ of the rats was determined by radioimmunoassay,and BAEP was recorded with the summation-average technique of computer from the skull surface of the rats at postnatal day 20,30,50,70 and 90.The changes of the peak latency（PL）,interpeak latency（IPL） and wave amplitude of BAEP in the hypothyroidism rats had been observed continuously for 3 months.Results: BAEP had been evoked from the rats of control group at postnatal day 20.But BAEP was not evoked from the rats of hypothyroidism group at postnatal day 20,and the PL of BAEP of them were much longer than that of control ones at postnatal day 30,50,70 and 90（P<0.01）.BAEP was evoked from the rats of replacement group at postnatal day 20,there was no significant difference between the PL of BAEP of them and that of control ones at postnatal day 20,30,50,70 and 90 except that the PL of wave Ⅳ of them was obviously longer than that of control ones at postnatal day 20, the PL of waveⅠof them was significantly shorter than that of control ones at postnatal day 30,and the PL of wave Ⅲ,Ⅳ and Ⅴ of them were obviously longer than that of control ones at postnatal day 50（P<0.01 or P<0.05）.TheⅠ-Ⅲ,Ⅲ-ⅤandⅠ-ⅤIPL of BAEP in the rats of hypothyroidism group were significantly longer than that of control ones at postnatal day 30,50,70 and 90（P<0.01 or P<0.05）.There was no significant difference of theⅠ-Ⅲ,Ⅲ-ⅤandⅠ-ⅤIPL between the rats of replacement group and control ones at postnatal day 20,30,50,70 and 90 except that theⅠ-Ⅲ IPL of them at postnatal day 20,and Ⅰ-Ⅲ and Ⅰ-Ⅴ IPL of them at postnatal day 50 were much longer than that of control ones（P<0.01 or P<0.05）.The wave amplitudes of BAEP in the rats of hypothyroidism group were much smaller than that of control one at postnatal day 30,50,70 and 90（P<0.01 or P<0.05）.There was no significant difference of the amplitudes between the rats of replacement group and that of control ones at the different age stages.Conclusion: The development of BAEP was significantly retarded in the rats with hypothyroidism in the period of brain development,and this retardation of brain development could be improved significantly by the replacement of thyroxine promptly.更多还原