Skip to main content
. 2007 Jun 11;27(16):5737–5745. doi: 10.1128/MCB.02265-06

FIG. 1.

FIG. 1.

Hypoxia increases replicative life span of human lung fibroblasts and mitochondrion-generated ROS. (a) PHLFs were cultured in either 21% O2 or 1.5% O2 and their PDs were monitored. (b) Senescence was detected by β-galactosidase activity in normoxia (PD29 and PD55) or hypoxia (PD27, PD55, and PD66). Scale bar, 132 μm. (c) Relative intracellular H2O2 levels of PHLFs, as determined by Amplex Red in 21% O2, 1.5% O2, or antimycin A (1 μg/ml) for 4 h in the presence of the mitochondrion-targeted antioxidant MitoQ (1 μM) or control compound TPMP (1 μM). *, P < 0.05 for TPMP at 21% O2 compared to TPMP at 1.5% O2 or antimycin A (n = 3). (d) Cytosolic ROS levels were detected by roGFP in PHLFs exposed to 21% O2 and 1.5% O2 for 24 and 48 h. Intracellular oxidant levels are displayed as a percentage of roGFP maximally oxidized by treating cells with 1 mM H2O2 for 5 min (n = 3).