Renal mRNA response to reduced perfusion pressure conserved despite denervation in mature ovine fetuses

Abstract

We hypothesized that renal denervation in mature ovine fetuses reduces renin mRNA response to 24 h of reduced renal perfusion pressure (RPP). Seven occluder (O) (132.4 ± 1.2 days gestation) and six control (C) (131.5 ± 1.2 days gestation) fetuses underwent left renal denervation. Postoperatively, O fetuses experienced 24 h of reduced RPP by suprarenal aortic occlusion. Femoral arterial blood pressure (FAB) and plasma active renin (pARC) and prorenin (pPRC) concentrations were obtained hourly for 6 h and at h 23 and 24. Renin mRNA was measured by RNase protection assay. We quantitated renin containing glomeruli by immunocytochemistry. Variables were compared by ANOVA. Mean O group FAB reduction from baseline was −6.60 ± 0.41 mmHg. pARC and pPRC increased with occlusion, renal ARC and renal PRC 1 did not increase with occlusion. No effect in renin mRNA or number of positive glomeruli was noted with denervation in the basal state; however, significant increases were noted in response to RPP irrespective of innervation status. In conclusion, 24 h or reduced RPP in mature ovine fetus increases renal renin mRNA and the immunocytochemical expression of renin. This response is conserved despite denervation.