Vascular tone regulation in renal interlobar arteries of male rats is dysfunctional after intrauterine growth restriction

Intrauterine growth restriction (IUGR) due to an adverse intrauterine environment predisposes to arterial hypertension and loss of kidney function. Here, we investigated whether vascular dysregulation in renal interlobar arteries (RIAs) may contribute to hypertensive glomerular damage after IUGR. In rats, IUGR was induced by bilateral uterine vessel ligation. Offspring of nonoperated rats served as controls. From postnatal day 49, blood pressure was telemetrically recorded. On postnatal day 70, we evaluated contractile function in RIAs and mesenteric arteries. In addition, blood, urine, and glomerular parameters as well as renal collagen deposition were analyzed. IUGR RIAs not only showed loss of stretch activation in 9 of 11 arteries and reduced stretch-induced myogenic tone but also showed a shift of the concentration-response relation of acetylcholine-induced relaxation toward lower concentrations. However, IUGR RIAs also exhibited augmented contractions through phenylephrine. Systemic mean arterial pressure [mean difference: 4.8 mmHg (daytime) and 5.7 mmHg (night)], mean glomerular area (IUGR: 9,754 +/- 338 mu m(2) and control: 8,395 +/- 227 mu m(2)), and urinary protein-to-creatinine ratio (IUGR: 1.67 +/- 0.13 g/g and control: 1.26 +/- 0.10 g/g) were elevated after IUGR. We conclude that male IUGR rat offspring may have increased vulnerability toward hypertensive glomerular damage due to loss of myogenic tone and augmented endothelium-dependent relaxation in RIAs. NEW & NOTEWORTHY For the first time, our study presents wire myography data from renal interlobar arteries (RIAs) and mesenteric arteries of young adult rat offspring after intrauterine growth restriction (IUGR). Our data indicate that myogenic tone in RIAs is dysfunctional after IUGR. Furthermore, IUGR offspring suffer from mild arterial hypertension, glomerular hypertrophy, and increased urinary protein-to-creatinine ratio. Dysregulation of vascular tone in RIAs could be an important variable that impacts upon vulnerability toward glomerular injury after IUGR.