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目的 探讨人牙髓细胞内Smad 2、3在转化生长因子 β1 (transforminggrowthfactor β1 ,TGF β1 )信号转导过程中的作用。方法 原代培养人牙髓细胞 ,用激光共聚焦显微镜观察TGF β1 刺激初期牙髓细胞内Smad 2、3由胞质向胞核转位的现象 ,同时采用Westernblot方法检测刺激后期Smad 2、3蛋白表达的变化。结果 TGF β1 刺激 2h内 ,Smad 2、3在胞质中表达渐弱 ,在胞核内表达渐强 ,呈现由胞质向胞核逐步转位的趋势。Smad 2蛋白总量在TGF β1 刺激前后几乎无变化 ,而Smad 3在刺激后 2 4h表达量明显下降 ,48h后表达十分微弱。结论 Smad 2、3可能是人牙髓细胞内TGF β1 的信号转导分子。TGF β1 刺激初期Smad 2、3通过发生转位参与转导TGF β1 信号至核内 ,刺激后期Smad 3表达水平的下调可能与TGF β1 负反馈调节自身的信号有关
Objective To investigate the role of Smad 2,3 in the signal transduction of transforming growth factor β1 (TGFβ1) in human dental pulp cells. Methods Human dental pulp cells were cultured in primary culture. Laser scanning confocal microscopy was used to observe the translocation of Smad 2,3 from cytoplasm to nucleus in primary dental pulp cells stimulated by TGF-β1. At the same time, Western blotting was used to detect the expression of Smad 2,3 Changes in expression. Results Within 2 hours after stimulation with TGFβ1, the expression of Smad 2 and 3 decreased in the cytoplasm and gradually increased in the nucleus, showing a gradual translocation from cytoplasm to nucleus. The total amount of Smad 2 protein almost did not change before and after stimulation with TGF β 1, whereas the expression of Smad 3 decreased significantly 24 h after stimulation and was very weak after 48 h. Conclusion Smad 2,3 may be the signal transduction molecule of TGF β1 in human dental pulp cells. In the early stage of TGFβ1 stimulation, Smad 2 and 3 are involved in the transduction of TGFβ1 signal into the nucleus via translocation. The down-regulation of Smad 3 expression in late stimulation phase may be related to TGFβ1 negative feedback regulation of its own signal