Salidroside reduces DNA strand breaks but not ROS. (A) Salidroside does not reduce H₂O₂-induced ROS. WT C57BL/6 mice were pretreated with one dose of salidroside (75μg/g body weight), NAC (50μg/g body weight), or MnTBAP (10μg/g body weight), followed by H₂O₂ (0.25 μmol/g body weight). BM cells were then harvested and labeled with CM-H2DCFDA for flow cytometry analysis of ROS in the LSK-gated cells. Representative images (left) and quantifications (right) were shown. (B) Salidroside reduces DNA strand breaks. BM cells from mice described in panel A were isolated by magnetic beads depletion, and then subjected to analysis for DNA strand breaks by the comet assay. The mean tail moment of untreated vehicle sample is expressed as 100%. Larger tail moment represents higher levels of DNA damage. For each treatment, 50 cells were scored from random sampling. (C) Salidroside reduces 8-oxodG. Protein extractions were prepared using low density BM cells from mice described in panel A. Whole cell lysates were then subjected to SDS-PAGE and immunoblotted with Western Blot antibodies for 8-oxodG and β-actin. (D) Repair kinetics. Low-density BM cells were pretreated with salidroside (250μM), NAC (500μM), or MnTBAP (250μM) for 2 hours, followed by H₂O₂ for additional 2 hours, and then released for indicated time intervals. Whole cell lysates were prepared and subjected to SDS-PAGE and immunoblotted with antibodies for 8-oxodG and β-actin.