Papel do barorreflexo na progressão da doença renal crônica

Abstract

Recently, blood pressure variability (BPV) has emerged as a new risk factor related with the development, progression and severity of chronic kidney disease (CKD). Despite this fact, few investigations have performed in order to access the renal function under a BPV condition and to better clarify how would this scenario contribute to the CKD progression. Therefore, the aim of the present study was to analyze the influence of BPV, induced by sinoaortic denervation, over the renal function and the progression of CKD in nephrectomized rats. Male Wistar rats (200 – 250 g) were divided in 4 experimental groups: Sham, sinoaortic denervated (SAD), nephrectomized (NX) and denervated + nephrectomized (SAD+NX). At the end of 6 weeks, hemodynamic variables and the renal function were analyzed. Almost all analyzed parameters were worsened by the association between SAD and 5/6 nephrectomy. Only NX and SAD+NX groups became hypertensive, with the highest level in SAD+NX rats. The baroreflex sensitivity was reduced in both SAD and NX but was additionally reduced in SAD+NX rats. The SAD, NX and SAD+NX rats exhibited rise in BPV, with the highest level observed in SAD+NX rats. Only nephrectomized rats presented hyperuremia which was 1.5 fold higher in SAD+NX. No difference was observed in glomerular filtration rate (GFR) and renal plasma flow (RPF) between SAD and Sham. Both nephrectomized rats showed reduction in GFR and RPF but RPF was additionally reduced in SAD+NX. There was also a reduction at renal blood flow (RBF) in all groups vs. Sham. At both nephrectomized groups this reduction reached about 92% of the Sham value in NX rats and 96% reduction in SAD+NX rats, in which the RBF value were half the value of NX rats. All groups exhibited increased in renal vascular resistance as compared to Sham as between groups. Thus, our results showed that an impairment in baroreflex function is associated with a worsening of CKD progression.