Effects of early overnutrition on the renal response to Ang II and expression of RAAS components in rat renal tissue

摘要

Abstract Background and aims The aim of this study was to analyze the effects of early overnutrition (EON) on the expression of the renin angiotensin aldosterone system (RAAS) components in renal cortex, renal arteries and renal perivascular adipose tissue (PVAT), as well as the vascular response of renal arteries to Angiotensin II (Ang II). Methods and results On birth day litters were adjusted to twelve (L12-control) or three (L3-overfed) pups per mother. Half of the animals were sacrificed at weaning (21 days old) and the other half at 5 months of age. Ang II-induced vasoconstriction of renal artery segments increased in young overfed rats and decreased in adult overfed rats. EON decreased the gene expression of angiotensinogen (Agt), Ang II receptors AT1 and AT2 and eNOS in renal arteries of young rats, while it increased the mRNA levels of AT-2 and ET-1 in adult rats. In renal PVAT EON up-regulated the gene expression of COX-2 and TNF-α in young rats and the mRNA levels of renin receptor both in young and in adult rats. On the contrary, Ang II receptors mRNA levels were downregulated at both ages. Renal cortex of overfed rats showed increased gene expression of Agt in adult rats and of AT1 in young rats. However the mRNA levels of AT1 were decreased in the renal cortex of overfed adult rats. Conclusion EON is associated with alterations in the vascular response of renal arteries to Ang II and changes in the gene expression of RAAS components in renal tissue. Highlights ? The renal expression of RAAS components is altered by early overnutrition. ? Early overnutrition modifies the contractile response of renal arteries to Ang II. ? Changes in the contractile response of renal arteries to Ang II are age dependent. ? Changes in the contractile response of renal arteries to Ang II may be affected by low grade inflammation of renal perivascular adipose tissue.