Collateral Circulation, Renal Function and Histology after Experimental Obstruction of Renal Veins

Experimental models of renal dysfunction in female rats. Functional and histological aspects after unilateral nephrectomy or ligation of right renal vein with kidney preservation

“…A major edema of the kidney a few hours after vein ligation is expected with better survival rates than after bilateral ligation of the renal veins, which is related to where the ligation is performed, being more successful when it is made next to the inferior vena cava, especially on the left, and also when the right and left veins are occluded in different days, not at the same time. Studies in dogs one to six weeks after the ligatures showed significant collateral circulation and only a transient alteration of excretion of electrolytes and mainly proteins 11 . Proteinuria found by Threefoot et al 11 showed a peak on the second day after vein ligation (four times above baseline values), becoming close to normal rates by the fifth day, reaching twice the baseline on the eighth day, remaining almost normal after this period, possibly due to the congestion and increase of venous pressure.…”

“…Studies in dogs one to six weeks after the ligatures showed significant collateral circulation and only a transient alteration of excretion of electrolytes and mainly proteins 11 . Proteinuria found by Threefoot et al 11 showed a peak on the second day after vein ligation (four times above baseline values), becoming close to normal rates by the fifth day, reaching twice the baseline on the eighth day, remaining almost normal after this period, possibly due to the congestion and increase of venous pressure. Likewise, the absence of collateral circulation makes stasis in the venous system to be followed by venous thrombosis and progression of functional alterations.…”

“…Likewise, the absence of collateral circulation makes stasis in the venous system to be followed by venous thrombosis and progression of functional alterations. These studies showed a survival rate for two weeks of eighty percent of the animals with ligation of one of the renal veins and twenty-seven percent when bilateral ligation of the veins was performed, especially when they were occluded next to the inferior vena cava 11 . In the experiment performed here, the attempts of simultaneous ligation of the renal veins with preservation of the kidneys, or ligation of the renal vein with contralateral nephrectomy, were incompatible with the survival of animals, tactics that were tried during the pilot study.…”

“…Threefoot et al 11 made plastic models with the injection of methacrylate in the arteries and veins and corrosion of tissues to assess the effectiveness of venous ligatures, confirming the early development (between one and three days), of collateral circulation for kidneys' drainage. The histological findings of these authors, when the right kidney was assessed, between the first and fifteenth day, were mostly infarction, bleeding and hemorrhagic necrosis.…”

“…In the 1950s and 1960s renowned experimental studies on the obstruction of the renal vein in dogs and mice, as well as its effects on renal function and histology were performed 11 , showing early alterations in both situations,…”