Research of Cytotoxicity and Gene Expression by Formaldehyde in the Food

Abstract:

To investigate the cytotoxic effects of formaldehyde in the food，we detect different concentrations of formaldehyde on the inhibition of cell growth，and use microarray technology to detect the influence of lymphocyte gene expression by formaldehyde in order to screen and analyze the differentially expressed genes related to toxicity and carcinogenicity of formaldehyde. By making MTT experiments，the cytotoxicity of formaldehyde was verified by comparing lymphocytes' growth curve and morphology. Peripheral blood lymphocytes were treated with 5×105 mol/L formaldehyde for 24 h.The total RNA from cells of the subjects of the treated group and the control group were isolated，then they were reversely transcribed and labeled with fluorescence dyes，and finally hybridized with human whole genome microarray（about 35 000 spots）. Microarray data was extracted after microarray scanning，and differentially expressed genes induced by formaldehyde were screened and analyzed by bioinformatics. In MTT experiments，human peripheral blood lymphocytes were treated with various doses of formaldehyde. The dose-effect relationship was also observed after treatment with high doses. 211 up-regulated and 113 down-regulated genes were screened after scanning and data extracting. Genes which significantly altered were represented by several categories，including oxidative stress，DNA repair，apoptosis，nucleic acid metabolism，cell cycle，oncogenesis，tumor suppression and so on. The result suggested the differential expression of these genes of OXR1，MLH1，TP53 may be the genetic basis of formaldehyde toxicity and carcinogenicity. The study provided theoretical evidence for elucidating the toxic and carcinogenic mechanism，detecting of the biomarker for formaldehyde exposure，and preventing the formaldehyde poisoning. It also verified the microarray technique is the feasible and advantageous in food toxicological research. It provides an experimental basis for the establishment of new methods to detect and study exposure of toxic substances.