中文摘要：

目的研究苯并（a）芘[B（a）P]对人胚肺成纤维细胞（HELF）的细胞周期分布及细胞周期蛋白D1（cyclin D1）和细胞周期蛋白依赖激酶4（CDK4）蛋白表达的影响,并探讨两种蛋白含量改变与细胞周期效应之间的关系。方法将反义cyclin D1质粒和反义CDK4质粒导入HELF细胞内,建立两种质粒稳定转染的细胞模型。用0.1、0.5、2.5和12.5μmol/L的B（a）P处理HELF细胞24h,用蛋白印迹方法检测cyclin D1和CDK4蛋白表达水平;利用流式细胞技术检测B（a）P处理对HELF细胞及两种稳定转染细胞系细胞周期的影响。结果成功建立了反义cyclin D1和反义CDK4稳定转染的细胞系。不同剂量B（a）P处理可引起cyclin D1蛋白表达的显著增加,但对CDK4蛋白表达无明显影响;2.5μmol/L的B（a）P处理HELF细胞24h后,引起其细胞周期G1期显著下降,S期显著增加;2.5μmol/L的B（a）P处理反义cyclin D1和反义CDK4稳定转染的HELF细胞24h后,对其细胞周期的分布无显著影响。结论Cyclin D1和CDK4基因均参与了B（a）P所致细胞周期改变过程,并发挥正性调节作用。

英文摘要：

Objective To study the effects of benzo（a）pyrene （B（a） P ） on the cell cycle distributions and expression of cell cycle regulated protein cyclin DI and CDK4 in human embryo lung fibroblasts （HELF）, and to investigate the relationship between the expression of both cyclin DI and CDK4 proteins and the cell cycle alterations. Methods Antlsense cyclin D1 cDNA and antisense CDK4 cDNA were respectively transfected into HELF cells, and two stable transfectants were established. The protein expression levels of cyclin DI and CDK4 were detected by western-blotting assay when HELF were treated with B（a）P at the doses of 0.1, 0.5, 2.5 and 12.5μmol/L B（a）P for 24h. And the flow cytometry assay was used for detecting the cell cycle effects in HELF cells and two stable transfectants. Results Two cell lines respectively expressed antisense cyclin DI RNA and antisense CDK4 RNA were successively established in the present study. The protein expressions of cyclin DI were greatly increased by B（a） P treatment, whereas B （a）P had no significant effects on the protein levels of CDK4. The cell cycle distributions were significantly altered at the level of 2 .5μmol/L B（a） P for 24h treatment. The cell numbers in G! phase significantly decreased. However, the cell numbers in S phase significantly increased. Conclusion Cyclin DI and CDK4 could be active genes and could positively regulate the cell cycle alterations induced by B（a）P.