Research Paper Volume 12, Issue 16 pp 16368—16389

Flavonoids from Rosa roxburghii Tratt prevent reactive oxygen species-mediated DNA damage in thymus cells both combined with and without PARP-1 expression after exposure to radiation in vivo

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Figure 4. Protective effect of FRT on radiation-induced DNA damage due to ROS in thymus tissue. (A) Effect of FRT on radiation-induced DNA damage measured by comet assay in thymus tissue of KO mice (**P <0.01 compared with normal group; ## P<0.01 compared with radiation group). Data was expressed as mean ±SD, n=5. (B) Protective effects of FRT on radiation-induced DNA fragments measured by DNA Ladder assay in thymus tissue of KO mice. PARP-1 knockout reduced radiation-induced DNA fragmentation in irradiated thymus cells (n=5). (C) The thymus was removed from WT mice and KO mice then ground into a cell suspension prior to allocation into a control group or 6 Gy radiation group. Thymus cells were harvested 1h after irradiation and γ-H2AX levels were measured by flow cytometry (** P<0.01; ## P<0.01). Data was expressed as mean ±SD, n=5. (D) Thymus cells were treated with FRT and inhibitor of ROS (NAC, 0.5 mM) 2 h before irradiation. Intracellular 53BP1 levels were measured by flow cytometry 1 h after irradiation. (** P<0.01; *** P<0.01). Data was expressed as mean ±SD, n=5. (E) Thymus cells were treated with FRT and inhibitor of ROS (NAC, 0.5 mM) 2 h before irradiation. Intracellular γ-H2AX levels were measured by flow cytometry 1 h after irradiation. (** P<0.01; *** P<0.01). Data was expressed as mean ±SD, n=5.