Possible radio-protective effect of folic acid supplementation on low dose ionizing radiation-induced genomic instability in vitro

Abstract

Ionizing radiation induces DNA damage through the production of single-strand breaks, double-strand breaks and reactive oxygen species. Folic acid (FA) can prevent DNA damage. We hypothesized that in vitro supplementation with FA will decrease the sensitivity of cells to genetic damage induced by low dose of ionizing radiation. Annexin V, comet and micronucleus assays were performed in cultured CHO cells. After 6 days of pre-treatment with 0, 100, 200 or 300 nM FA cultures were exposed to radiation (100 mSv). Two un-irradiated controls were executed (0 and 100 nM FA). Data were statistically analyzed with X2-test and linear regression analysis (P  0.05). We observed a significant decrement in the frequency of apoptotic cells as the folic acid concentration increases (P < 0.05). The same trend was observed when analyzing DNA damage and chromosomal instability (P < 0.05 for 300 nM). For the linear regression analysis, only micronuclei frequencies shows significant differences (R2 = 94.04; P < 0.01). Our results indicate that folate supplementation has an important impact on genetic damage and should be taken into account when studying the effect of low dose radiation in environmental or occupational exposure.