Post-myocardial infarction left ventricular myocyte remodeling: are there gender differences in rats?

Previous studies have shown gender differences in left ventricular remodeling after myocardial infarction. Results are varied, however, and reliable, comprehensive data for changes in cardiac myocyte shape are not available.Young adult female and male Sprague-Dawley rats were used in this study and randomly assigned to the myocardial infarction and sham myocardial infarction groups. Myocardial infarction was produced by ligation of the left descending coronary artery. Four weeks after surgery, left ventricular echocardiography and hemodynamics were performed before isolating myocytes for size determination.In general, left ventricular functional changes after myocardial infarction were comparable. Females developed slightly, but significantly, more left ventricular hypertrophy than males, and this was reflected by the relative increases in left ventricular myocyte volume. In both males and females, however, myocyte hypertrophy was due exclusively to lengthening of myocytes with no change in myocyte cross-sectional area.This study demonstrates that post-myocardial infarction changes in LV function and myocyte remodeling are remarkably similar in young adult male and female rats.