In order to identify the role of reactive oxygen species (ROS) in cardiac hypertrophy, we examined the effect of N-2-mercaptopropionyl glycine (MPG) on cardiac hypertrophy.

Recent in vitro studies have suggested that ROS play an important role as a second messenger in cardiac hypertrophy. It was therefore thought to be of particular value to examine the relevance of studies using in vitro models for cardiac hypertrophy in an in vivo setting.

The transverse thoracic aorta in mice was constricted, and MPG (100 mg/kg) was infused intraperitoneally twice daily. The animals were assessed seven days after the operation for hemodynamic functions, oxidative stress and antioxidative enzyme activities.

Banding of the transverse aorta in mice resulted in an increase in the ratio of heart weight to tibia length and the appearance of an endogenous atrial natriuretic factor messenger ribonucleic acid (mRNA) seven days postoperatively. Administration of MPG significantly attenuated the hypertrophic responses induced by pressure overload. Cardiac hypertrophy was accompanied by increases in heme oxygenase-1 mRNA expression and lipid peroxidation, which was eliminated by the treatment with MPG. Pressure overload led to increases in antioxidant enzyme activities, such as superoxide dismutase and glutathione peroxidase, but not catalase, activity.

Our results indicated that oxidative stress was increased in our model and that it plays an important role in the development of cardiac hypertrophy.