The aim of this study was to investigate whether (-)-epicatechin (EC) can induce DNA damage and apoptosis of cancer cells in the spleen of rat with acute myeloid leukemia. Healthy and leukemic rats were given EC by gavage at a dose of 40 mg/kg b.w. for 22 consecutive days. Spleen cells were subjected for analysis of DNA damage and apoptosis. The amount of DNA damage was estimated by the comet assay, while apoptosis was examined by flow cytometry using Annexin V staining. Leukemic cells were identified in the spleen cells by indirect immunofluorescence using RM-124 antibody followed by flow cytometry analysis. The results show that EC did not affect DNA damage in the splenocytes of healthy rats, but significantly increased the extent of DNA strand breaks in the spleen cells of leukemic animals. EC administration to leukemic rats induced a significant increase in the level of Annexin V-positive leukemic cells, but the level of non-leukemic Annexin V-positive cells remained unchanged in comparison to control. The percentage of leukemic cells decreased significantly under EC influence comparing to the untreated group. The results of the study reveal that EC could be used as an effective supplement of standard therapy against acute myeloid leukemia.
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