目的：　研究甲状腺激素对新生鼠小脑神经生长相关蛋白质 (GAP 43)表达的影响。方法：　选用他巴唑复制的甲状腺机能减退大鼠模型,用免疫组织化学方法结合图像分析对正常及甲状腺机能减退新生鼠小脑皮质的GAP 43动态变化进行研究。结果：　生后 15d及 30d甲状腺机能减退新生鼠的体重 (14.0 0± 3.0 3) g,(2 9.88± 8.92 ) g、脑重 (0 .82 5± 0 .0 78) g,(1.15 0± 0 .110) g均较正常同龄新生鼠低 (33.0 0± 4.12 ) g,(80 .0 0± 14.2 8) g ;(1.0 98± 0.040)g,(1.430±0.114) g(P<0.001) ;生后15d甲状腺机能减退新生鼠的血清甲状腺激素水平T3 (0.26±0.28)nmol/L,T4 (10.00±4.80)nmol/L也较正常同龄鼠降低T3 (1.052±0.143)nmol/L,T4 (93.85±7.92)nmol/L(P<0.001);正常及甲状腺机能减退新生鼠小脑皮质GAP 43分布趋势相似,均表现为分子层染色最重,神经元胞体不染色;图像分析显示甲状腺机能减退新生鼠小脑皮质分子层GAP 43灰度值在生后15d(171.35± 0.69)明显高于正常组 (160.83±4.69) (P<0.001);其灰度值在生后30d(149.60±3.94)则低于正常对照组 (159.42±6.66) (P<0.01)。结论：　在脑发育过程中,甲状腺激素可直接或间接影响小脑皮质GAP 4

OBJECTIVE: To study the effect of thyroid hormones on expression of GAP 43 in cerebellum of neonatal rats. METHODS Immunocytochemical method and image analysis were used to observe changes of GAP 43 in cerebellum of both normal and hypothyroid neonatal rats. RESULTS: The body weight (14.00 ± 3.03 g, 29.88 ± 8.92 g), brain weight (0.825 ± 0.078) g, (1.150 ± 0.110) g and thyroid hormones levels T 3: (0.26 ± 0.28) nmol/L, T 4: (10.00 ± 4.80) nmol/L of 15 or 30 day hypothyroid rats were significantly weaker than that of age matched euthyroid rats (33.00 ± 4.12) g, (80.00 ± 14.28) g; (1.098 ± 0.040) g, (1.430 ± 0.114) g; T 3: (1.052 ± 0.143) nmol/L, T 4:( 93.85 ± 7.92) nmol/L (P<0.001). The distribution tendency of GAP 43 in cerebellun was similarly in experimental pups as compared to age matched controls. In hypothyroid pups, the distribution tendency of GAP 43 in cerebellum was similar to that of age matched controls. The analysis of image shows that the grey values of GAP 43 was higher in hypothyroidism than that of normal pups at postnatal 15th days (171.35 ± 0.69 vs 160.83 ± 4.69, P< 0.001 ), but lower at pastnatal 30th days (149.60 ± 3.94 vs 159.42 ± 6.66, P< 0.01). CONCLUSIONS: Thyroid hormones affect expression of GAP 43 directly or indirectly. By regulating GAP 43, thyroid hormones have an effect on G 0 protein signal transduction system and may lead to brain developmental retardation.