treatment: 150 uM H2O2 added and then cultured at 21% O2 tension in vitro for 3 days
treatment: 150 uM H2O2 added and then cultured at 10 % O2 tension in vitro for 3 days
treatment: 10 % O2 tension in vitro for 3 weeks
treatment: 21% O2 tension in vitro for 3 days
treatment: 10 % O2 tension in vitro for 3 days