Exercise-induced expression of heme oxygenase-1 in human lymphocytes

The aim of the present investigation was to determine whether an acute bout of exercise increases heme oxygenase-1 (HO-1) mRNA accumulation in human lymphocytes. Eight male subjects performed separate exercise and rest trials in a randomised order at least 10 days apart. In the exercise trial subjects ran for 75-min at a speed corresponding to 70% maximal oxygen uptake, and in the resting trial subjects sat calmly in the laboratory for an equivalent period of time. Lymphocytes were harvested from blood samples taken before and after each trial. Total RNA was isolated and used to determine the fold-change in HO-1 mRNA accumulation relative to baseline values using real time reverse transcription-polymerase chain reaction. HO-1 protein was determined by Western blotting. Six of the eight subjects showed an increase in HO-1 mRNA greater than two-fold after exercise. The median peak fold-change was 2.7 fold with one subject showing a particularly pronounced response (20-fold) 24 h post-exercise. In the rest trial the level of HO-1 mRNA did not change over the period of investigation. There was also an increase in HO-1 protein 2 h after exercise. These results complement an earlier study showing that acute exercise of a different type (half marathon) leads to an increase in HO-1 expression in lymphocytes.