ABSTRACT
Background: Tenofovir disoproxil fumarate (TDF), a widely prescribed component in antiretroviral regimens, has been associated with nephrotoxicity. Nebivolol is a third generation selective ß-1 adrenergic receptor blocker and may protect renal structure and function through the suppression of oxidative stress and enhancement of nitric oxide (NO) synthesis. We aimed to investigate whether nebivolol could be an effective therapeutic strategy to mitigate tenofovir-induced nephrotoxicity. Methods: We allocated Wistar rats to four groups: control (C), received a standard diet for 30 days; NBV, received a standard diet for 30 days added with nebivolol (100 mg/kg food) in the last 15 days; TDF, received a standard diet added with tenofovir (300 mg/kg food) for 30 days; and TDF+NBV, received a standard diet added with tenofovir for 30 days and nebivolol in the last 15 days. Results: Long-term exposure to tenofovir led to impaired renal function, induced hypertension, endothelial dysfunction and oxidative stress. Nebivolol treatment partially recovered glomerular filtration rate, improved renal injury, normalized blood pressure and attenuated renal vasoconstriction. Administration of nebivolol contributed to reductions in asymmetric dimethylarginine (ADMA) levels as well as increases in endothelial nitric oxide sintase (eNOS) accompanied by renin-angiotensin-aldosterone system downregulation and decreases in macrophage and T-cells infiltrate. Furthermore, nebivolol was responsible for the maintenance of the adequate balance of thiobarbituric acid reactive substances (TBARS) and glutathione (GSH) levels and it was associated with reductions in NADPH oxidase (NOX) subunits. Conclusion: Nebivolol holds multifaceted actions that promote an advantageous option to slow the progression of kidney injury in tenofovir-induced nephrotoxicity.
ABSTRACT
Snakebites have been recognized as a neglected public health problem in several tropical and subtropical countries. Bothrops snakebites frequently complicate with acute kidney injury (AKI) with relevant morbidity and mortality. To date, the only treatment available for Bothrops envenomation is the intravenous administration of antivenom despite its several limitations. Therefore, the study of novel therapies in Bothrops envenomation is compelling. The aim of this study was to evaluate the protective effect of Allopurinol (Allo) in an experimental model of Bothrops jararaca venom (BJ)-associated AKI. Five groups of Wistar rats were studied: Sham, Allo, BJ, BJ+Allo, BJ+ipAllo. BJ (0.25 mg/kg) was intravenously injected during 40'. Saline at same dose and infusion rate was administered to Sham and Allo groups. Allo and BJ+Allo groups received Allo (300 mg/L) in the drinking water 7 days prior to Saline or BJ infusion respectively. BJ+ipAllo rats received intraperitoneal Allo (25 mg/Kg) 40' after BJ infusion. BJ rats showed markedly reduced glomerular filtration rate (GFR, inulin clearance) associated with intense renal vasoconstriction, hemolysis, hemoglobinuria, reduced glutathione and increased systemic and renal markers of nitro-oxidative stress (Nitrotyrosine). Allo ameliorated GFR, renal blood flow (RBF), renal vascular resistance and arterial lactate levels. In addition, Allo was associated with increased serum glutathione as well as reduced levels of plasma and renal Nitrotyrosine. Our data show that Allo attenuated BJ-associated AKI, reduced oxidative stress, improved renal hemodynamics and organ perfusion. It might represent a novel adjuvant approach for Bothrops envenomation, a new use for an old and widely available drug.
