| Objective: To explore the folic acid in the role of effect of N-methyl-N’-nitro-Nnitrosoguanidine(MNNG) on normal Kazakh’s esophageal epithelial cells in general biology and index of epigenetics, in order to provide the theoretical evidences for the prevention and treatment of esophageal cancer in Kazakh nationality. Method: 1. Cell proliferation assay was detected by MTT method, cell cycle was detected by flow cytometry. 2. The change of total DNA methylation level was detected by HPLC. 3. The methylation of MTHFR and FRα were detected by BSP. 4. The mRNA and protein level of MTHFR, FRα, DNMT1, DNMT3 a and DNMT3 b were tested by RT-PCR and Western-Blot.Results: With the decrease of the concentration of folic acid and the increases of the concentration of MNNG, the following results appeared:( 1)Morphology of normal Kazakh esophageal epithelial cells had significant changes. The number of the dead cells were gradually increased, and different degree of rupture appeared in cell nucleus. The cytoplasm was uneven and the integrity of cell was destroyed. The cells’ sensitivity to the damage of MNNG were significant increased, particularly on 96 h.(2)The inhibition rate in normal Kazakh esophageal epithelial cells was higher, and there was a significant difference(P<0.01).(3)The overall methylation level of Kazakh normal esophageal epithelial cells was significantly reduced(P<0.01).( 4) The enzymes of DNMT1,DNMT3 a and DNMT3 b in Kazakh normal esophageal epithelial cells were significantly increased(P<0.01).( 5) The methylation frequency of MTHFR and FRα in Kazakh normal esophageal epithelial cells were significantly increased. The P1-1 fragment, P1-2fragment in the district of the promoter of MTHFR and P2-1 fragments in the district of the promoter of FRα showed more obvious(P<0.01).(6)The expression of mRNA and protein of DNMT1, DNMT3 a and DNMT3 b in normal Kazakh esophageal epithelial cells were significantly increased(P<0.01). The expression of mRNA and protein of MTHFRand FRα gene were significantly increased(P<0.01). Conclusion: The reduction of the concentrations of folic acid promotes the Kazak normal esophageal epithelial cells’ damage which caused by MNNG. Sufficient folic acid play a protective role in the damage caused by MNNG. |
