Relationship between remodeling and function of left ventricle and angiotensin II AT1 receptor expression after myocardial infarction in rats

Abstract

Objective: To determine the relationship between remodeling and dysfunction of left ventricle (LV) and the expression of the angiotensin II AT1 receptor mRNA after myocardial infarction (MI) in rats.

Methods: Nine MI rats (Group A) and 8 sham-operated rats (Group B) were studied by both Doppler echocardiography and Dot blot using Digoxingenin-labelled cDNA probes.

Results: Compared with Group B, Group A showed the increase in LV internal diastolic diameter (0.87 +/- 0.06 mm vs 0.66 +/- 0.03 mm, respectively, P < 0.01) and volume (0.73 +/- 0.09 ml vs 0.51 +/- 0.05 ml, P < 0.01). In addition, thinning of anterior wall, thickening of posterior wall, increasing of peak early filling velocity (peak E), decreasing of late filling velocity (peak A) and increasing of the E/A were demonstrated in MI rats 7 weeks after MI. The levels of the cardiac angiotensin II AT1 receptor mRNA in Group A were higher than those of Group B (2.2-fold).

Conclusions: Seven weeks after MI in rats, character of LV remodeling and dysfunction were developed and the expression of cardiac angiotensin II AT1 receptor mRNA was increased.