人胚呼吸道上皮细胞非时序DNA合成

UNSCHEDULED DNA REPAIR SYNTHESIS IN HUMAN FETAL RESPIRATORY EPITHELIAL CELLS

为研究和比较化学致癌物对人呼吸道上皮细胞和纤维母细胞的损伤及损伤后DNA修复合成的差异,作者用直接致癌物4-硝基喹啉-1-氧化物(4-NQO)和间接致癌物3,4-苯并芘(BaP)处理人胚鼻咽、气管上皮细胞和纤维母细胞,用放射自显影术测定这3种细胞的非时序脱氧核糖核酸合成(UDS)。用4-NQO处理后,这3种细胞的UDS均呈明显的剂量依赖(dose dePendency)关系,但气管和鼻咽上皮细胞UDS平均分别是纤维母细胞的3.0和2.4倍。用BaP处理后,气管和鼻咽上皮细胞UDS呈现明显的剂量依赖关系,而纤维母细胞未见这种关系。气管和鼻咽上皮细胞的UDS平均分别是纤维母细胞的8.6和3.0倍。

In order to study and compare the difference in DNA repair synthesis induced by chemical carcinogens in human respiratory epithelial cells and fibroblast cells, nasophar-yngeal and tracheobronchial epithelial cells and fibroblast cells were treated with dire carcinogen 4-nitroquinoline-1-oxide (4-NQO) and indirect carcinogen benzo(a) pyrene (BaP). The unscheduled DNA synthesis(UDS) of cells was assessed using autoradiography. The frequency of UDS showed clear dose dependency in all cell types treated with 4-NQO, but UDS occurred 3.0 and 2.4 times more frequently in the tracheobronchial and nasopharyngeal epithelial cells than in the fibroblast cells, respectively. After treatment with BaP, the frequency of UDS showed clear dose dependency only for both epithelial cell types, not for the fibrolast cells. 8.6 and 3.0 times more UDS were in tracheobronchial and nasopharyngeal epithelial cells than in fibroblast cells, respectively. These results indicatet that thenasop haryng response of human respiratory epithelial cells to some DNA damaging agents is different from that of fibroblast cells. The respiratory epithelial cells are more sensitive to damage by chemical carcinogens than fibroblast cells and are the chief target cells of chemical carcinogens.