Figure 5.

Reactive oxygen species (ROS) levels in Leydig cells were quantified using 2′,7′-dichlorodihydrofluorescein staining and flow cytometry. Cellular ROS levels, as reflected by relative DCFH intensity, were markedly elevated in Leydig cells isolated from the old rats. Chronic stress also significantly increased ROS production in Leydig cells from old rats compared to cells from young control rats. Each sample was run in duplicate, and the figure is representative of three assays. *P<0.05 compared with the Young group.