The in vivo effect of hemin on both brain oxidative stress and heme oxygenase-1 (HO-1) induction was studied. A marked increase in lipid peroxidation was observed 1 h after hemin administration and antioxidant enzymes significantly decreased 3 h after hemin injection. HO-1 activity appeared 6 h after treatment, peaking 9 h after hemin administration. Such induction was preceded by a decrease in GSH pool and an increase in hydrogen peroxide concentration. Iron ferritin levels and ferritin content began to increase 6 h after HO-1 induction, and these increases remained high for at least 24 h after hemin injection. Administration of bilirubin entirely prevented HO-1 induction as well as the generation of oxidative stress parameters. These results indicate that the induction of heme oxygenase by hemin may be a general response to oxidant stress, by increasing bilirubin and ferritin levels and could therefore provide a major cellular defense mechanism against oxidative damage.
Copyright 2002 S. Karger AG, Basel