The Effect of Tadalafil on Renal Fibrosis Induced by Ureteral Obstruction / Efecto del Tadalafil en la Fibrosis Renal Inducida por Obstrucción Uretral

ABSTRACT Objective: It has been reported that phosphodiesterase-5 (PDE-5) inhibitors improve kidney function during acute and chronic renal failure. This study aimed to determine the possible therapeutic effects of tadalafil, a specific PDE-5 inhibitor, on renal fibrosis induced by unilateral ureteral obstruction (UUO). Methods: Male Sprague-Dawley rats were used and randomly divided into three groups (n = 6) as sham-operated, UUO and tadalafil-treated (10 mg/72 hours, ig) UUO (UUO+T) groups. Unilateral ureteral obstruction was induced by complete ligation of the left ureter and 14 days after surgery creatinine clearance, urinary cyclic guanosine monophosphate (cGMP), renal alpha-smooth muscle actin (α-sma) and transforming growth factor βeta (TGF-β) levels, as well as histologic changes, were observed in all the animals. Results: Unilateral ureteral obstruction-induced renal fibrosis was confirmed by increased α-sma level, collagen deposition, tubular dilation, inflammatory cell infiltration and necrosis. An increased renal TGF-β level and decreased urinary cGMP level was also observed in obstructed animals in addition to reduced creatinine clearance. Tadalafil treatment, which restored the animals 'urinary cGMP level, significantly attenuated the fibrotic changes and TGF-β increase in their kidneys. Conclusion: This study suggests that tadalafil treatment ameliorates renal fibrosis by reducing TGF-β expression and may have important clinical relevance since tadalafil is currently used clinically to treat erectile dysfunction and pulmonary hypertension.

RESUMEN Objetivo: Se ha reportado que los inhibidores de la fosfodiesterasa-5 (PDE-5) mejoran las funciones renales durante la insuficiencia renal aguda y crónica. Este estudio tuvo por objetivo determinar los posibles efectos terapéuticos del tadalafil - un inhibidor específico de la PDE-5 - sobre la fibrosis renal inducida por una obstrucción ureteral unilateral (OUU). Métodos: Se utilizaron ratas machos Sprague-Dawley, divididas de manera aleatoria en tres grupos (n = 6): operación simulada, OUU y tratamiento con tadalafil (10 mg/72 horas, IG), y OUU (OUU+T). La obstrucción uretral unilateral fue inducida por una ligadura completa del uréter izquierdo y 14 días después de la cirugía, se observaron niveles de monofosfato de guanosina cíclico (GMP) urinario, alfa-actina de músculo liso (α-SMA), y factor de crecimiento transformante βeta (FCT-β), así como cambios histológicos en todos los animales. Resultados: La fibrosis renal inducida por obstrucción uretral unilateral fue confirmada por un aumento del nivel de α-SMA, deposición de colágeno, dilatación tubular, infiltración de células inflamatorias y necrosis. También se observó un aumento del nivel de FCT-β renal y una disminución del nivel de GMP urinario en los animales con obstrucción, además de una reducción del aclaramiento de la creatinina. El tratamiento con tadalafil, que restauró el nivel de GMP urinario de los animales, atenuó significativamente los cambios fibróticos y el aumento de FCT-β en los riñones. Conclusión: Este estudio sugiere que el tratamiento con tadalafil mejora la fibrosis renal al reducir la expresión de FCT-β y puede tener una importante relevancia clínica por cuanto el tadalafil se usa hoy día clínicamente para tratar la disfunción eréctil y la hipertensión pulmonar.

Positive outcomes of phosphodiesterase type 5 inhibitor on histopathologic and biochemical changes induced by ureteral obstruction

SUMMARY OBJECTIVES: We examined the effects of tadalafil, one of the phosphodiesterase type 5 (PDE5) inhibitors, in a rat model of with partial and complete unilateral ureteral obstruction (UUO). METHODS: The rats were divided into 5 groups: sham (n=6), partial unilateral ureteral obstruction (PUUO, n=6), PUUO with tadalafil treatment (PUUO+T; Cialis, 10 mg/72 h, intragastric; Lilly, Indianapolis, Indiana, USA), complete unilateral ureteral obstruction (CUUO, n=6), and CUUO with tadalafil treatment (CUUO+T). RESULTS: Fifteen days after the UUO, the ureter presented changes in the layers of urothelium and significant infiltration of inflammatory cells in the PUUO and CUUO groups. Compared with the sham, PUUO and CUUO groups had severe increased inflammatory cell infiltration. The urothelial epithelium exhibited cell degeneration and loss because of the swollen, atrophic, and denuded epithelial cells in the PUUO and CUUO groups. In the PUUO+T and CUUO+T groups, the urothelium revealed less epithelial cell degeneration and loss. The expressions of α-smooth muscle actin (α-SMA) and transforming growth factor-β (TGF-β) exhibited up-regulation in the PUUO and CUUO groups. The expression of TGF-β decreased positively correlated with that of α-SMA in the tadalafil therapy groups, PUUO+T and CUUO+T. CONCLUSION: The phosphodiesterase type 5 inhibitor's tadalafil reduced expressions of α-SMA and TGF-β in the obstructed ureters, measured by biochemical examinations. In addition, tadalafil decreased urothelium degeneration due to the decreased epithelial cell loss and inflammatory cell infiltration. Our results show that tadalafil prevents or slows down the onset of ureter inflammation and urothelial degeneration in rats with UUO.

RESUMO OBJETIVOS: Examinamos os efeitos do tadalafil em um dos inibidores da fosfodiesterase tipo 5 (PDE5) em um modelo de rato com obstrução ureteral unilateral parcial e completa (UUO). MÉTODOS: Os ratos foram divididos em cinco grupos: sham (n = 6), obstrução ureteral unilateral parcial (PUUO, n = 6), PUUO com tadalafil (PUUO T; Cialis, 10 mg/72 h, intragástrica; Lilly, Indianapolis, Indiana, EUA), completa obstrução ureteral unilateral (CUUO, n = 6) e CUUO com tratamento com tadalafil (CUUO T). RESULTADOS: Quinze dias após a UUO, o ureter apresentou alterações nas camadas de urotélio e infiltração significativa de células inflamatórias nos grupos PUUO e CUUO. Em comparação com os grupos sham, PUUO e CUUO, houve um aumento grave da infiltração de células inflamatórias. O epitélio urotelial exibiu degeneração e perda celular devido às células epiteliais inchadas, atróficas e desnudas nos grupos PUUO e CUUO. Nos grupos PUUO T e CUUO T, o urotélio revelou menor degeneração e perda de células epiteliais. Nós mostramos que a expressão da actina do músculo liso-α (α-SMA) e do fator de crescimento transformador-β (TGF-β) foram exibidas como sub-regulação nos grupos PUUO e CUUO. A expressão do TGF-β foi diminuída positivamente correlacionada com a da α-SMA nos grupos de terapia com tadalafil, PUUO T e CUUO T. CONCLUSÃO: O tadalafil do inibidor da fosfodiesterase tipo 5 reduziu as expressões α-SMA e TGF-β nos ureteres obstruídos, medidos por exames bioquímicos. Além disso, o tadalafil diminuiu a degeneração do urotélio devido à diminuição da perda de células epiteliais e da infiltração de células inflamatórias. Nossos resultados mostram que o tadalafil previne ou retarda o início da inflamação do ureter e degeneração urotelial em ratos com UUO.

Effects of tadalafil to prevent injury on corpus cavernosum after vascular or nervous peri-prostatic bundle injury. Experimental model in rats

Abstract Purpose: To evaluate the effects of tadalafil (TD) in preventing histological alterations of the corpus cavernosum caused by isolated lesions of cavernous nerve (ILCN) and artery (ILCA) in rats. Methods: Fifty male Wistar rats were randomly assigned in five groups: G1: control; G2: bilateral ILCN; G3: bilateral ILCA; G4: ILCN+TD; G5: ILCA+TD. The cavernous bodies were submitted to histomorphometry, immunohistochemistry and biochemical analysis. Results: Nerve density was significantly higher in G2 and G4 compared to control (22.62±2.84 and 19.53±3.47 vs. 15.72±1.82; respectively, p<0.05). Smooth muscle density was significantly lower in G2 and G3 in comparison to G1 (12.87±1.90 and 18.93±1.51 vs. 21.78±1.81, respectively; p<0.05). A significant decrease in the sinusoidal lumen area was observed in G2 compared to controls (5.01±1.62 vs. 9.88±3.66, respectively; p<0.05) and the blood vessel density was increased in G2 and G3 (29.32±4.13 e 20.80±2.47 vs. 10.13±2.71, p<0.05). Collagen density was higher in G3 compared to G1 (93.76±15.81 vs. 64.59±19.25; p<0.05). Conclusions: Histomorphometric alterations caused by ILCN were more intense than those produced by vascular injury, but the collagen analyses showed more fibrosis in animals with ILCA. TD was effective in preventing the majority of the alterations induced by the periprostatic bundle injury.

Oxidative stress assessment in intestine of newborn rats submitted to hypoxia and reoxygenation with tadalafil

Abstract Purpose: To evaluate the functional and structural response of tadalafil effects in the intestinal mucosa, using an experimental model of hypoxia and reoxygenation injury in rats. Methods: The animals were divided into 4 groups: CTL, H/R, H/R+Td and M+Td. The newborn rats allocated in groups H/R, H/R+Td and M+Td were submitted twice a day, to a gas chamber with CO2 at 100% for 10 minutes and afterward reoxygenation with O2 at 98% for 10 minutes, in the three first days of life. Tadalafil dose was given to newborn of group H/R+Td and to the pregnant rat of group M+Td. Histological analysis was made with hematoxylin-eosin technique and oxidative stress through nitrite and nitrate levels and lipid peroxidation. Results: The histological analysis showed a reduction of mucosa alterations in the groups that received tadalafil. In the oxidative stress evaluation, occurred an increase of NO levels and less lipidic peroxidation in the ileum segments that received tadalafil. Conclusion: Tadalafil provides tissue protection when administered independently to both, pregnant or newborns.

Tadalafil protector effect during ischemia-reperfusion in rats

Abstract Purpose: To evaluate histological parameters in rat renal tissue after tadalafil use during hot ischemia for 45 minutes and reperfusion for 24 hours. Methods: Twenty rats were divided into 2 groups. In the experimental group 10 mg/kg of tadalafil was used per gavage before the procedure. All cases underwent left partial nephrectomy, followed by 45 minutes of warm ischemia. Left nephrectomy of the remaining kidney was performed after 24 hours from the initial procedure. The histological parameters analyzed were: detachment of tubular cells, accumulation of desquamated cells in the proximal tubule, loss of brush border, tubular cylinders, interstitial edema, leukocyte infiltration, capillary congestion, vacuolization, tubular dilatation, necrosis and collapse of the capillary tuft. Results: Two rats from each group died and were excluded from the study. Tadalafil significantly reduced leukocyte infiltration (p = 0.036). The remaining histological parameters did not show statistical difference between the groups. Conclusion: The use of tadalafil during warm ischemia and reperfusion demonstrates statistically significant reduction of leukocyte infiltration in the renal interstitium.

The renoprotective effect of oral Tadalafil pretreatment on ischemia/reperfusion injury in rats

Abstract Purpose: To evaluate the effect of tadalafil in renal ischemia/reperfusion (I/R) injury in rats Methods: Group I/R saline rats (n=6) were subjected to 45 minutes of left renal ischemia and treated with saline; the I/R tadalafil rats (n=6) received oral 10mg/kg tadalafil microemulsion one hour before ischemia. In both groups, 8 hours after ischemia, laboratory analysis were performed Results: Better tissue perfusion was lower in ischemic left/kidney than in right/kidney in saline group, suggesting reduced kidney clearance. Fluorescence in left/kidneys of tadalafil treated rats was lower than in right/kidneys (difference not significant). The fluorescence signal intensity in kidneys of tadafil treated rats was higher than in saline rats. TNF-α levels were significantly lower in I/R tadalafil group rats compared to I/R saline group (154±10.3 vs 391.3±12.3), as well as IL-1β (163.4±13.2 vs 279±11.5pg/dL), and IL-6 (122.9±8.1 vs 173.7±6.3 respectively; p=0.0001). Urea, creatinine and C-reactive protein were significantly lower in tadafil treated rats then in saline group Conclusion: Tadalafil therapy decreased the expression of circulating pro-inflammatory cytokines in a renal I/R rodent model, while improving kidney function proofs.