血清对Hela细胞内硫醇浓度和甲醛诱导性DNA-蛋白质交联（DPC）的影响

吸入性甲醛如何将其遗传毒性从呼吸器官经血液转移全身?这是揭示"甲醛致白血病"这个科学问题的关键.以新生牛血清(NBS)为"模拟血液",以Hela细胞为实验材料,采用体外甲醛染毒实验,研究了培养基血清对细胞内硫醇浓度,以及对甲醛诱导性DNA-蛋白质交联(DPC)的影响.结果表明,当培养基中未添加血清时,250μmol·L-1甲醛仅引起较低水平的交联效应,同时细胞内硫醇浓度水平也较低;而加入1%和10%新生牛血清以后,甲醛诱导的DPC均显著上升(p<0.01,p<0.05),同时细胞内硫醇浓度水平也显著上升(p<0.05,p<0.01).培养基中新生牛血清能够再生Hela细胞内的硫醇,同时促进细胞DPC的形成.这可能为理解甲醛远距离毒性,解释吸入甲醛是否能导致白血病提供了基础.

Effects of Serum on Cellular Thiol C0ncentration and DNA-Protein Crosslink (DPC) Induced by Formaldehyde in Hela Cells

How does inhaled formaldehyde transfer the genotoxicity from exposure organ to site distant organs via blood?This is the key question to understand leukemia induced by formaldehyde. To answer this question, we used new born calf serum(NBS)as"blood"and Hela cells as materials to investigate its effects on cellular thiol concentration and DNA-protein crosslink(DPC)induced by formaldehyde. Results showed that when NBS was absent, 250μmol·L-1 formaldehyde induced relatively low amount of DPC, while cellular thiol concentration was also low. In contrast, DPC formation and cellular thiol concentration were significantly elevated in the presence of 1% and 10% NBS(p<0.01, p<0.05). These results indicated that NBS could regenerate cellular thiol concentration and stimulate DPC formation as a consequence in formaldehyde exposed cells. This effect may provide a basis for the understanding of site distant toxicity of formaldehyde and to explain whether inhaled formaldehyde could induce leukemia.