FIG 5.

Levels of ROS in M. tuberculosis-infected macrophages treated with first-line antibiotics in the presence and absence of NAC. THP-1 cells were fixed by 4% paraformaldehyde, and ROS measurements were performed by fluorescent staining using a cellROX Red assay kit from Life Technologies. There was a significant decrease in ROS amount in M. tuberculosis-infected samples treated with NAC. A significant decrease of ROS levels was also observed when M. tuberculosis-infected samples were treated with INH, INH plus NAC, RIF, RIF plus NAC, EMB, EMB plus NAC, PZA, and PZA plus NAC. There was also a significant decrease in ROS levels in antibiotic-plus-NAC categories compared to stand-alone antibiotic categories. The mean cell intensity was analyzed by ImageJ software. Data represent means ± SE from 6 trials. *, P < 0.05 when comparing the antibiotic plus NAC to the antibiotic alone or infected NAC to infected control. ***, P < 0.0005 when comparing the antibiotic plus NAC to the antibiotic alone or infected NAC to infected control. ###, P < 0.0005 when comparing each antibiotic category to the infected control. ####, P < 0.00005 when comparing each antibiotic category to the infected control.