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目的分析3,3’,5-三碘甲腺原氨酸(T3)对体外培养的大鼠大脑皮层神经元G蛋白Go的α亚单位(Goα)基因表达的影响。方法取孕19 d的胚胎大鼠大脑皮层神经元,于含15％胎牛血清的DMEM培养基中培养。7 d后神经元分为5组,分别置于不同的培养基:DMEM+15％胎牛血清(A组); DMEM+15％去甲状腺激素的胎牛血清(B组);含0．5 nmol／L T3的DMEM+15％去甲状腺激素的胎牛血清(C组);含5 nmol／L T3的DMEM+15％去甲状腺激素的胎牛血清(D组);含50 nmol／L T3的DMEM+ 15％去甲状腺激素的胎牛血清(E组)。继续培养7 d,收集细胞,抽提总RNA,以竞争性RT-PCR分析各组神经元GoαmRNA水平。结果B、D和E组神经元GoαmRNA水平显著低于A组(均P<0．01);C组神经元GoαmRNA水平显著高于A、B、D和E组(P<0．01);B、D和E组之间则差异无统计学意义(P> 0．05)。结论T3对体外培养的神经元Goα基因的表达有双重调节作用:在一定浓度范围内T3对培养的神经元Goα基因的表达有下调作用;但如果培养基中缺乏T3,神经元Goα基因的表达水平也很低。甲状腺激素对神经元Goα基因表达的调节作用可能是其调节脑发育的机制之一。
Objective To investigate the effect of 3,3 ’, 5-triiodothyronine (T3) on the gene expression of Goα in Go protein of cultured rat cerebral cortex neurons. Methods Cortical neurons of embryonic rat embryos 19 days old were cultured in DMEM medium containing 15% fetal bovine serum. After 7 days, the neurons were divided into five groups and placed in different media: DMEM + 15% fetal bovine serum (group A), DMEM + 15% thyroid hormone-free fetal bovine serum (group B) (group C) with 15 nmol / L T3 DMEM + 15% thyroid hormone; Group D with 5 nmol / L T3 DMEM + 15% thyroid hormone; DMEM + 15% thyroid hormone-free fetal bovine serum (group E). After cultured for 7 days, the cells were harvested and total RNA was extracted. Goa mRNA levels in neurons of each group were analyzed by competitive RT-PCR. Results The levels of GoαmRNA in neurons in groups B, D and E were significantly lower than those in group A (all P <0.01). The levels of Goα mRNA in neurons in group C were significantly higher than those in groups A, B, D and E (P <0.01). There was no significant difference between B, D and E groups (P> 0.05). Conclusion T3 can regulate the expression of Goα gene in vitro. T3 can down-regulate the expression of Goα gene in cultured neurons in a certain concentration range. However, in the absence of T3, Goα gene expression in neurons The level is also low. The regulatory effect of thyroid hormones on Goα gene expression in neurons may be one of the mechanisms by which thyroid hormones regulate brain development.