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Direct Evidence that in Rat the Renal Interstitium Contracts in vivo
Author(s) -
RodríguezMartínez Manuel,
LópezRodríguez Juan Francisco,
FloresSandoval Omar,
CalvoTurrubiartes Miriam Zarahí,
LLamazaresAzuara Lilia
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.701.4
Subject(s) - in vivo , saline , bolus (digestion) , medullary cavity , medicine , chemistry , endocrinology , contraction (grammar) , renal blood flow , hematocrit , perfusion , kidney , urology , biology , microbiology and biotechnology
Dibutyryl‐cAMP abolishes the RIHP increase in response to renal medullary direct interstitial volume expansion (DIVE = 100 μl in 30 s) with 0.9% saline solution (SS) in hydropenic rats (FASEB J 30:739.9: 2016), suggesting that renal interstitium contracts in vivo . To assess more directly if such an event happens in vivo, we decided to evaluate in hydropenic rats the time course of RIHP before and after either an acute sham (CTR group, n = 9) or an acute (1s) real renal interstitial medullary application (RIMA) of a 5μ bolus of either vehicle (0.9% SS, SS group, n = 9) or 10 μM alpha‐trinositol (anti‐inflammatory drug that increases β1 integrin‐mediated collagen fiber network contraction, A‐T group, n = 9). Left subcapsular RIHP (subcRIHP) and % change of renal outer medullary blood flow (%ΔRoMBF by L‐D) were continuously measured in anesthetized rats with right nephrectomy, acute left renal denervation, hormonal clamp and renal perfusion pressure control (100 mmHg), before (baseline = BL = 30 min) and after sham or real RIMA of 5 μl bolus of either SS or A‐T. There were no differences among groups in body weight, hematocrit nor plasma protein concentration at any time. The table below shows both BL RIHP and ΔRIHP (RIHPafter – RIHPbefore) values (mean ± SEM) obtained at different times points after sham or real RIMA. Three were no differences among groups in BL RIHP. Overall RMMANOVA of ΔRIHP data showed no time effect, but if group (P<0.0004) and time * group interaction effects (P<0.009); 1WRMMANOVA:* P = 0.05, ** P <0.001 vs. Before; 1WANOVA + Tukey test: • P<0.04 vs. SS group, •• P<0.001 vs. CTR group. The %ΔRoMBF showed a similar decrease over time in the three groups. CONCLUSIONS The results show that acute RIMA of alfa‐trinositol is able to increase the RIHP in hydropenic rats by a mechanism independent of increased renal medullary blood flow, which reinforces the idea of that, at least in hydropenia, renal interstitium contracts in vivo . Support or Funding Information C15‐FAI‐04‐96.66/UASLPsubcRIHP (mmHg)Before RIMA subcΔRIHP (mmHg)After RIMA Group BL 15 min 30 min 45 min 60 minCTR 3.0 ± 0.1 −0.85 ± 0.22 ** −1.11 ± 0.16 ** −1.17 ± 0.19 ** −1.16 ± 0.17 **SS 3.1 ± 0.03 −0.30 ± 0.20 −0.15 ± 0.36 −0.38 ± 0.56 −0.51 ± 0.55A‐T 3.1 ± 0.06 0.54 ± 0.25 •◆ 1.26 ± 0.51 *•◆ 0.76 ± 0.37 ◆ 0.68 ± 0.38 ◆