Aldosterone infusion alone in normal rats on a normal salt diet significantly induced cardiac hypertrophy and severe inflammatory responses via oxidative stress.
Does aldosterone infusion alone induce cardiac hypertrophy and inflammation in rats on a normal salt diet?
Aldosterone alone induces cardiac hypertrophy and inflammation via oxidative stress independently of blood pressure, even without salt loading or nephrectomy.
Absolute Event Rate: 233% vs 172.8%
p-value: p=<0.01
Aldosterone is known to play a role in the pathophysiology of some cardiovascular diseases. However, previous studies on aldosterone infusion have been mostly performed in animals receiving sodium loading and uninephrectomy, and thus the cardiac action of aldosterone alone remains to be fully clarified. The present study was undertaken to investigate the direct cardiac action of aldosterone infusion alone in rats not subjected to salt loading and uninephrectomy. Aldosterone (0.75 microg/h) was subcutaneously infused into rats via an osmotic minipump for 14 days. Aldosterone infusion, under a normal salt diet, induced only a slight increase in the blood pressure of normal rats throughout the infusion. However, aldosterone significantly induced cardiac hypertrophy, as shown by echocardiography and measurement of cardiomyocyte cross-sectional area. Furthermore, aldosterone caused not only cardiac interstitial macrophage infiltration but also cardiac focal inflammatory lesions, which were associated with an increase in cardiac monocyte chemoattractant protein-1 (MCP-1) and osteopontin mRNA. The slight elevation of blood pressure by aldosterone infusion was completely prevented by tempol, the superoxide dismutase mimetic. However, tempol failed to suppress cardiac hypertrophy, the formation of inflammatory lesions, and upregulation of cardiac MCP-1 and osteopontin by aldosterone, while N-acetylcysteine could inhibit all of them. Our data provide evidence that aldosterone alone can induce cardiac hypertrophy and severe inflammatory response in the heart, independently of blood pressure, even in the absence of salt loading or nephrectomy. Aldosterone seems to induce cardiac inflammation and gene expression via oxidative stress that is inhibited by N-acetylcysteine but not by tempol.
Yoshida et al. (Sat,) conducted a other in Normal rats (not subjected to salt loading or uninephrectomy). Aldosterone vs. 5% ethanol infusion (Control) was evaluated on Cardiomyocyte cross-sectional area (µm2) (p=<0.01). Aldosterone infusion alone in normal rats on a normal salt diet significantly induced cardiac hypertrophy and severe inflammatory responses via oxidative stress.