Potential mechanisms of low salt diet induced cardiac diseases

We hypothesized that a LS intake leads to a cascade of events involving increases in plasma AII, the AT1 receptor, NADPH oxidase and O2˙ production and ultimately to reduced NO bioactivity. This reduced NO bioactivity results in altered control of the coronary circulation and cardiac metabolism. This study was undertaken to determine the global changes in cardiac gene expression in dogs fed LS diet (0.5% NaCl) for two weeks. Cardiac RNA was extracted from the control and LS fed groups (n=4). Statistical significance (P≤0.05; fold change of ±2) showed that there were 443 genes that changed, 110 decreasing and 333 increasing. All of the differentially expressed genes were grouped into functional categories based on their Gene Ontology. Adult male mongrel dogs (n=10, BW;25-28kg) were put on LS which contains 0.5% sodium chloride for two weeks. RNA was isolated using Trizol reagent. RNA from each sample was used to generate a high fidelity cDNA using the labeling protocols for sample preparation recommended by Affymetrix. Data and statistical analysis were performed in Genetraffic using a t-test and with variance stabilization. Differences were considered statistically significant at a nominal significance of p≤0.05 and at least ±2 fold change in expression between control (n=3), and LS dogs (n=4).