Renal function and histology after acute hemorrhage in rats under dexmedetomidine action

Abstract

Purpose: About 50 % of indications for dialysis in acute renal failure are related to problems originated during the perioperative period. Intraoperative hemodynamic changes lead to renal vasoconstriction and hypoperfusion. Previous studies have not defined the dexmedetomidine renal role in hemorrhage situations. This study evaluated the effect of dexmedetomidine on renal function and histology after acute hemorrhage in rats. Methods: Covered study with 20 Wistars rats, anesthetized with sodium pentobarbital, 50 mg. kg -1 , intraperitoneal, randomized into 2 groups submitted to 30% volemia bleeding: DG -iv dexmedetomidine, 3 µg. kg -1 (10 min) and continuous infusion -3 µg. kg -1 . h -1; CGpentobarbital. For renal clearance estimative, sodium p-aminohippurate and iothalamate were administered. Studied attributes: heart rate, mean arterial pressure, rectal temperature, hematocrit, iothalamate and p-aminohippurate clearance, filtration fraction, renal blood flow, renal vascular resistance, and histological evaluations of the kidneys. Results: DG showed smaller values of heart rate, mean arterial pressure, and renal vascular resistance, but iothalamate clearance and filtration fraction values were higher. There was similarity in p-aminohippurate clearance and renal blood flow. Both groups had histological changes ischemia-like, but dexmedetomidine determined higher tubular dilatation scores. Conclusion: In rats, after acute hemorrhage, dexmedetomidine determined better renal function, but higher tubular dilation scores. Key words: Kidney. Hypotension. Dexmedetomidine. Pentobarbital. RESUMO Objetivo: Cerca de 50% de indicações de diálise em insuficiência renal aguda vêm de problemas do perioperatório. Alterações na hemodinâmica intra-operatória levam a vasoconstrição renal e hipoperfusão. Estudos prévios não definiram o papel renal da dexmedetomidina em hemorragia. Foram estudados os efeitos da dexmedetomidina na função e histologia renais, em ratos, após hemorragia aguda. Métodos: Estudo encoberto com 20 ratos Wistar, anestesiados com pentobarbital sódico intraperitoneal, 50 mg. kg -1 , divididos aleatoriamente em 2 grupos sob sangramento de 30% da volemia: GDdexmedetomidina iv, 3 µg. kg -1 (10 min), e infusão contínua, 3 µg. kg ; GC -pentobarbital. Para estimar depuração renal, administraram-se para-aminohipurato e iotalamato de sódio. Atributos estudados: freqüência cardíaca, pressão arterial média, temperatura retal, hematócrito, depuração de para-aminohipurato e iotalamato, fração de filtração, fluxo sangüíneo renal, resistência vascular renal, análise histológica dos rins. Resultados: Em GD, houve valores menores de freqüência cardíaca, pressão arterial média e resistência vascular, mas valores maiores de depuração de iotalamato e fração de filtração. A depuração de para-aminohipurato e o fluxo sangüíneo foram similares nos grupos. As alterações histológicas foram compatíveis com isquemia e houve maior dilatação tubular em GD. Conclusão: Em ratos, após hemorragia aguda, a dexmedetomidina determinou mel...

Molecular targets and mechanism of action of dexmedetomidine in treatment of ischemia/reperfusion injury (Review)

“…DEX administration directly inhibits the release of renin in the kidney, which promotes renal arterial vasodilatation (80). DEX also reduces renal vascular resistance and increases the glomerular filtration rate and filtration fraction, thus promoting histological changes consistent with pathological features of ischemia (77). These findings support the hypothesis that DEX protects against renal injury caused by I/R.…”

“…Pre-or post-treatment with DEX provided cytoprotection and improved tubular architecture and function following renal ischemia. Treatment of rats with DEX following acute hemorrhage resulted in improved renal function, but in higher tubular dilation scores (77). In anesthetized dogs, low doses of DEX inhibited vasopressin secretion, causing aqueous diuresis (78).…”

Dexmedetomidine Infusion for Analgesia Up to 48 Hours After Lung Surgery Performed by Lateral Thoracotomy

“…By modulating the release of catecholamines, dexmedetomidine decreases sympathetic tone and attenuates the stress response to surgery and anesthesia. Some data suggest that dexmedetomidine is protective of major organs and can prevent acute brain dysfunction or delirium postoperatively (25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38). Th is may be of great signifi cance in this often elderly and high-risk cardiac group of patients.…”

Renal Function after Coronary Artery Bypass Graft Using Dexmedetomidine

“…In contrast, other authors of histological studies found that using DEX in rats caused dilation, degeneration, and necrosis of renal tubules after hemorrhage of 30% of volemia, without replacing this loss. However, there was reduced renal vascular resistance in organ function, with increased glomerular filtration and renal filtration fraction [31].…”