The potential mechanism for the elevated ROS levels.

<p>(A) Detection of mitochondrial ROS in live cells. Live MSCs were treated with Ara-C (100 mM for 24 hours) or without. Red fluorescence indicates the presence of mitochondrial ROS, while blue fluorescence indicates nuclei stained with Hoechest 33342. (B) Median Fluorescence Intensity (MFI) of mitochondrial ROS in the control and Ara-C groups. (C) MFI of total ROS measured by the CM-H₂DCFDA probe in the control and Ara-C groups. (D) Gene expression of NOX2 and NOX4 in the control and Ara-C groups. (E) The mean increase/decrease of mitochondrial ROS and total ROS in Ara-C cells treated with DPI or Mito-Tempo. (F) The expression and activity of major antioxidant enzymes, including Cu/Zn-SOD, Mn-SOD and CAT. (G) The level of the antioxidant molecule GSH in the control and Ara-C groups. (H) The expression of major antioxidant enzymes <i>in vivo</i>. (I) The expression of major antioxidant enzymes on Day 7 and Day 14 of MSC differentiation induced by adipose differentiation medium. *<i>P</i> < 0.05.