Studies on Formation of Liquid and Gaseous Formaldehyde-Induced DNA-Protein Crosslinks in Rat Marrow Cells

Formaldehyde (HCHO) is a genotoxicant which is suspected to have the ability to induce leukemia in epidemiology field. However, little is known about the possible mechanism how this agent induces leukemia. In this study, rat marrow cells are chosen to be the exposure targets to both liquid and gaseous formaldehyde. DNA-protein crosslinks are evaluated via KCl-SDS assay while single cell gel electrophoresis technique (comet assay) is used to test the DNA strand breaks of bone marrow cells. Our results show that low concentrations of formaldehyde (liquid: 5μmol·L-1 and 25μmol·L-1, gaseous: 0.5mg·m-3 and 1.0mg·m-3) can cause significant DNA breakage (p <0.01); the higher concentrations of liquid formaldehyde (liquid: 125μmol·L-1 and 625μmol·L-1, gaseous: 3.0mg·m-3) can cause significant DPC (p<0.01; p<0.05) compared with the control. The results suggest that formaldehyde can induce DNA damage in rat marrow cells which imply formaldehyde is highly possible to induce leukemia.