Effect of dioxins in mother's milk on sister chromatid exchange frequency in infant lymphocytes

Sister chromatid exchange (SCE) frequency which was an index to the synthetic and sharp genetic toxicity was examined using the infant lymphocyte cells around postnatal of 1 year. SCE frequency as the control culture which was treated with the solvent, DMSO, alone (SCEcontrol) was 8.2 +/- 0.9/cell and as cultured with 7,8-benzoflavone (ANF) (SCEANF) was 11.8 +/- 1.4/cell. In addition, the difference of SCEANF and SCEcontrol, namely, delta SCEs became 3.6 +/- 1.3/cell. The concentration of the dioxins in the mother's milk, which had taken by the infants, in the 2-4 month postpartum was 0.95 +/- 0.51 pg-TEQ/g in the male infants, and 0.97 +/- 0.48 pg-TEQ/g in the female ones. The sex difference could not be recognized in contamination levels of the dioxins in mother's milk. The SCE frequency of the infant lymphocytes was examined in order to evaluate the genetic toxicity of the dioxins which had contaminated mother's milk. As the result, either the SCE frequencies or delta SCEs did not show any significant correlation to the dioxins. Therefore, the dioxins were considered not to induce the genetic toxicity such as the SCEs at the present levels of pollution in Japanese mother's milk around postnatal of 1 year.