Fig. 9. Reactive Oxygen Species (ROS) measurement by confocal microscopy. ROS levels in HL-60 cells were measured prior freezing [Control] and post freezing in DMSO alone or DMSO + Nig and Sal. (a) represents real time ROS levels were also measured 1 hour, 5 hours and 24 hours post thaw of HL-60 cells frozen with DMSO [DMSO] and DMSO +Nig (150 µM) + Sal (100 µM) [N + S]. ROS levels were expressed in percentage (ROS count/Cell number x 100) (b) and data are presented as a mean ± SEM [n=3].