Fig. 4.  Heme oxygenase-1 (HO-1) messenger ribonucleic acid expression in rat myocardium after hypoxic late preconditioning with 16% oxygen. Representative reverse transcriptase–polymerase chain reaction analysis experiments of a time course (normoxic control, 6 and 28 h poststimulus). Summarized data presenting ratio of heme oxygenase-1 to glyceraldehyde-3-phosphate dehydrogenase (GAPDH) are shown. All data are presented as mean ± SD unless otherwise specified. *P < 0.05 vs.  normoxic control.