中文摘要：

目的观察转化生长因子β3（TGF—β3）自反馈调节信号通路中正向调节因子的作用。方法用外源性TGF—β3诱导大鼠肝星状细胞系（HSC—T6），在不同时间点用荧光素酶报告基因分析法检测TGF．83的启动子活性，Western印迹法检测cAMP反应元件（CRE）结合蛋白1（CREB-1）和磷酸化CREB-1的表达，实时荧光定量PCR法检测CREB-1mRNA的表达情况。结果外源性TGF—β3处理HSC—T6后，TGF—β3启动子活性表现出时间依赖性增高，并于诱导后24h达峰值[10．68±0．57，2．2倍于对照组（4．83±0．56）]。TGF-β3启动子的基础活性下降了85％（0．73±0．03，P〈0．05）。外源性TGF-β3可在短时问内上调磷酸化CREB-1的表达，与对照组（比值为1）相比，15min即可见明显增加（1．5倍于对照组），1h时其表达量达到最大值（2．0倍于对照组），12h略见下降（1．9倍于对照组，均P〈0．05）。外源性TGF-β3对HSC—T6中CREB-1 mRNA和CREB-1蛋白的表达均无影响（均P〉0．05）。结论外源性TGF—β3可促进TGF—β3启动子活性增强，且CRE位点在外源性TGF—β3介导的TGF—β3启动子活性中发挥重要作用；外源性TGF—β3可活化CREB-1，但不能促进CREB-1蛋白及mRNA的表达。

英文摘要：

Objective To explore the effects of exogenous transforming growth factor-β3 （ TGF-β3 ） on the activities of its promoter and cAMP-responsive element binding protein-1 （ CREB-1 ） in rat hepatic stellate cell （ HSC-T6 ）. Methods HSC-T6 was cultured and treated with or without exogenous TGF-β3 （ 10 μg/L）. Then cell extracts, total RNA and nuclear proteins were collected at different time points. The specimens were detected by luciferase reporter assay, Western blotting and real-time RT-PCR （reverse transeription-polymerase chain reaction ） respectively. Results After treatment, the activity of TGF-β3 promoter peaked at 24 h （ 10. 68 ±0. 57 vs 4. 83±0. 56, 2. 2 folds vs control）. And the mutational CRE site completely blocked the activity of TGF-β3 promoter（0. 73 ± 0. 03, P 〈 0. 05）. In addition, exogenous TGF- β3 increased the expression of phospho-CREB-1 in a time-dependent manner. It peaked at 1 h （2.0 folds vs control） and declined slowly. And exogenous TGF-β3 had no effect on the mRNA and protein expressions of CREB-1 （ P 〉 0.05 ）. Conclusion The activity of TGF-β3 promoter is up-regulated hy exogenous TGF-β3. And CRE site in TGF-β3 promoter region is important for the transcription of TGF-β3 gene in HSC-T6. While activating CREB-1, exogenous TGF-β3 has no effect on the expressions of CREB-1 protein and mRNA.