Department of Occupational and Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
Hum Exp Toxicol. 2011 Dec;30(12):1904-13. doi: 10.1177/0960327111401637. Epub 2011 Mar 10.
Benzo(a)pyrene (BaP) has been shown to be an inducer of apoptosis. However, mechanisms involved in BaP-induced mitochondrial dysfunction are not well-known. In this study, human fetal lung fibroblasts cells were treated with BaP (8, 16, 32, 64 and 128 μM) for 4 and 12 h. Cell viability, intracellular level of reactive oxygen species (ROS), total antioxidant capacity (T-AOC), mitochondrial membrane potential (ΔΨ(m)) and cytochrome c release were determined. Changes in transcriptional levels of p53-dependent apoptotic genes (p53, APAF1, CASPASE3, CASPASE9, NOXA and PUMA) were measured. At time point of 4 h, BaP induced the intracellular ROS generation in 64 (p < .05) and 128 μM BaP groups (p < .01) but decreased the T-AOC activities in 32, 64 (p < .05 for both) and 128 μM BaP groups (p < .01). At time point of 12 h, ΔΨ(m) significantly decreased in ≥32 μM BaP groups (p < .05 for all). Amount of mitochondrial cytochrome c significantly increased in 128 μM BaP group (p < .01). Transcriptional levels of CASPASE3, CASPASE9, APAF1 and PUMA were up-regulated in all BaP groups (p < .05 for all) and in ≥32 μM groups for NOXA (p < .05). But only in 16 μM BaP group a relatively little expression of p53 mRNA was observed (p < .05). The results indicate that in the earlier period BaP promoted the generation of excessive ROS and subsequently the mitochondrial depolarization, whereas transactivations of the p53-dependent apoptotic genes were significantly induced at the later period.
苯并(a)芘 (BaP) 已被证明可诱导细胞凋亡。然而，BaP 诱导线粒体功能障碍的机制尚不清楚。在这项研究中，用人胎儿肺成纤维细胞分别用 BaP（8、16、32、64 和 128 μM）处理 4 和 12 h。测定细胞活力、细胞内活性氧（ROS）水平、总抗氧化能力（T-AOC）、线粒体膜电位（ΔΨ(m)）和细胞色素 c 释放。测定 p53 依赖性凋亡基因（p53、APAF1、CASPASE3、CASPASE9、NOXA 和 PUMA）转录水平的变化。在 4 h 时，BaP 在 64（p <.05）和 128 μM BaP 组中诱导细胞内 ROS 生成（p <.01），但在 32、64（p <.05）和 128 μM BaP 组中降低 T-AOC 活性（p <.01）。在 12 h 时，在≥32 μM BaP 组中，ΔΨ(m)显著降低（p <.05）。线粒体细胞色素 c 的含量在 128 μM BaP 组中显著增加（p <.01）。所有 BaP 组（p <.05）和≥32 μM 组的 CASPASE3、CASPASE9、APAF1 和 PUMA 的转录水平均上调（p <.05），但仅在 16 μM BaP 组观察到 p53 mRNA 的相对少量表达（p <.05）。结果表明，在早期 BaP 促进了过多 ROS 的生成，随后导致线粒体去极化，而 p53 依赖性凋亡基因的反式激活则在后期明显诱导。
