甲醛暴露对离体细胞活性及其内源性甲醛含量变化的影响

发布时间：2018-03-23 07:10

本文选题：甲醛　切入点：甲醛脱氢酶　出处：《华中师范大学》2013年硕士论文　论文类型：学位论文

【摘要】：甲醛是一种常见的室内空气污染物,甲醛污染具有来源广,毒性大,污染时间长,毒性机理不明确等特点。甲醛化学性质活泼,能与脂类,蛋白质,核酸共价交联反应,甲醛也是生物内源性的代谢产物,各种RNA和DNA脱甲基化反应都能产生低浓度的甲醛。 2004年国际癌症研究所(IARC)将甲醛确立人类致癌物,它可引起人类鼻咽癌,但是对于甲醛会导致白血病,世界卫生组织认为存在有力的流行病学证据但分子生物学的证据不够充分,需要进一步研究证明。本文旨在从分子生物学的角度研究甲醛在细胞内的代谢途径及其毒性机制。为研究甲醛暴露对离体细胞毒性的影响是否由其自身基团造成,实验选用了不同浓度的甲醛及其衍生物甲醇、甲酸以及醛基的同类物乙醛四种物质对离体培养Hela细胞进行染毒处理,测定细胞的氧化损伤水平以及细胞内甲醛含量以及甲醛脱氢酶表达量变化。实验结果发现,染毒1小时后,低浓度的甲醛(10μmol/L)对细胞的生长具有促进作用,高浓度甲醛(62.5μmol/L浓度及以上)抑制细胞的生长,在125μmol/L浓度下四种化学物均影响细胞生长,其中甲醛对细胞活性影响最大。甲醛、甲酸、甲醇、乙醛四种物质暴露,对于离体培养细胞均能产生氧化损伤且影响细胞内源性甲醛含量,引起细胞内甲醛含量升高,并诱导细胞内甲醛脱氢酶的表达上调,各组甲醛脱氢酶的表达量分别是空白组为1,甲醇组10.6,甲醛组10.4,甲酸组0.9,乙醛组1.1,其中,甲醛和甲醇染毒后,甲醛脱氢酶的表达量与空白组有显著差异。实验结果表明,外界甲醛可以通过细胞膜进入细胞,短时间内能影响细胞内的甲醛含量,且能诱导细胞内甲醛脱氢酶高效表达,使进入细胞内甲醛被降解,在24h修复后,甲醛恢复到本底浓度,细胞内甲醛的含量处于一个稳定的水平。甲醛的毒性不仅仅是其中的碳原子,羟基,或羧基基团的降解产生氧化损伤,其毒性可能通过其它机制发生,甲醛可能作为一种的信号分子,在细胞生长过程中起着重要的生物学作用。
[Abstract]:Formaldehyde is a common indoor air pollutant. Formaldehyde pollution has many characteristics, such as wide source, high toxicity, long time of pollution, unclear toxic mechanism, etc. Formaldehyde is chemically active and can be cross-linked with lipids, proteins and nucleic acids. Formaldehyde is also a biological endogenous metabolite. All kinds of RNA and DNA demethylation reactions can produce low concentration of formaldehyde. In 2004, the International Cancer Institute (IARC) established formaldehyde as a human carcinogen, which can cause human nasopharyngeal carcinoma, but the WHO believes that there is strong epidemiological evidence but not enough molecular biological evidence for formaldehyde to lead to leukemia. The aim of this paper is to study the metabolic pathway of formaldehyde in cells and its toxic mechanism from the point of view of molecular biology. In order to study whether the effect of formaldehyde exposure on in vitro cytotoxicity was caused by its own groups, different concentrations of formaldehyde and its derivative methanol were used in the experiment. In vitro Hela cells were treated with formic acid and aldehyde. The levels of oxidative damage, the content of formaldehyde and the expression of formaldehyde dehydrogenase were measured. One hour after exposure, 10 渭 mol 路L ~ (-1) of formaldehyde at a low concentration could promote the growth of the cells, and a high concentration of 62.5 渭 mol/L and above) inhibited the growth of the cells. At the concentration of 125 渭 mol/L, all the four chemicals affected the growth of the cells. Formaldehyde has the greatest effect on cell activity. Exposure to formaldehyde, formic acid, methanol and acetaldehyde can cause oxidative damage and increase the content of intracellular formaldehyde in cultured cells. The expression of formaldehyde dehydrogenase was up-regulated in the cells. The expression of formaldehyde dehydrogenase was 1 in blank group, 10.6 in methanol group, 10.4 in formaldehyde group, 0.9 in formic acid group and 1.1 in acetaldehyde group. The results showed that formaldehyde could enter the cells through the cell membrane, affect the formaldehyde content in the cells in a short time, and induce the high expression of formaldehyde dehydrogenase in the cells. After 24 hours of repair, formaldehyde is restored to its background concentration, and the content of formaldehyde in cells is at a stable level. The toxicity of formaldehyde is not just carbon atoms, hydroxyl groups, The degradation of carboxyl groups may cause oxidative damage, and its toxicity may occur through other mechanisms. Formaldehyde, as a signaling molecule, may play an important biological role in the process of cell growth.
【学位授予单位】：华中师范大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：R114

【共引文献】