[Effect of Na2SeO3 on the damages of genetic materials induced by MNNG in children's foreskin fibroblasts in vitro].

In order to study the effect of selenium on anticarcinogenesis, micronuclei (MN) and chromosome aberrations (CA) were used as the indexes to reflect the damages on the genetic materials induced by MNNG in children's foreskin fibroblasts in vitro. In the MN test, the final concentrations of Na2SeO3 were 10(-7), 10(-6), 10(-5) and 10(-4) M and MNNG, 10(-5)M. In the CA test, Na2SeO3 were used in 10(-7), 10(-6) and 10(-5)M and MNNG, 10(-6)M as the final concentrations. Relative to the time of MNNG treatment, the cells were exposed to Na2SeO3 4 hours before and at the same time as with the carcinogen. The results showed that the MN% (number of cells out of one thousand MN) was reduced from 4.31 +/- 0.91% to 1.55 +/- 0.54% and 1.54 +/- 0.54% (P less than 0.05), respectively. The CA% (the percentage of the cell with CA) was reduced from 86 +/- 7% to 34 +/- 9% and 33 +/- 9% (P less than 0.05), respectively. However there was no like results when the cells were treated with Na2SeO3 and MNNG simultaneously. Na2SeO3 had no significant protective effects on the cells when the concentration was 10(-7)M. If the dose was 10(-4)M or more, Na2SeO3 became toxic to the cells. The results suggested that the protection of Na2SeO3 on the damages of genetic materials induced by MNNG be time and dose dependent.