The influence of phosphorothioate oligodeoxynucleotides on various organs in vivo

To characterize the distribution and toxicity of phosphorothioate antisense oligodeoxynucleotides ([S]ODNs) in vivo, the mice, previously injected with BV173 leukemic cells (Philadelphia chromosome-positive chronic myeloid leukemia blast-crisis), received intravenously 26-mer BCR-ABL antisense oligodeoxynucleotides (1 mg/mouse/day) for 9 consecutive days. Our investigation revealed that [S]ODNs were distributed to almost all organs except the brain with the highest level in the liver, spleen and kidneys. They were also detected in CD10+ leukemic cells isolated from spleen and bone marrow. Intracellular distribution assay showed the presence of [S]ODNs most prominently in nuclear and cytoplasmic fractions. Our data demonstrated no significant toxicity of [S]ODNs except the increase in spleen weight.