Reduced Cardiac Performance after Differential Pharmacological Stress in Streptozotocin-Induced Diabetic Rats

Diabetes Mellitus (DM) is a main risk factor for heart failure. A hallmark of this common complication is a disturbed conductibility of the left ventricle (LV). In this regard, diabetic cardiomyopathy is a significant entity, which could manifest as impaired cardiac performance in the absence of coronary artery disease, systemic hypertension or valvular heart disease that result from metabolic derangement present in diabetes. Among others, structural changes in extracellular matrixand myocyte damage contain hallmarks of this disease. Abnormalities in these compartments may result in left ventricular dysfunction (LV).

The Application of streptozotozin (STZ) to rats is a well established model of type 1 DM. We previously showed in this model severe impaired LV function under basal conditions in a chronic stage of STZ-induced DM. We further identified pathophysiological mechanisms, which could be responsible for this disturbed cardiac phenotype. This includes endothelial dysfuntion, cardiac fibrosis, inflammation and disturbed myocardial calcium regulation as well as neurohumoral activation.Whereas the cardiac phenotype under basal conditions in the chronic stage in STZ rats is well characterized, we analysed in the present study in vivo the time-dependent LV conductibility in this model. Therefore we measured LV function in STZ diabetic rats on two different time points under basal and under different pharmacological stress conditions using invasive LV microconductance catheter technique. Read more................