Efeitos cistométricos da castração hormonal e administração diária de tadalafila em camundongos com hiperatividade detrusora induzida pela deficiência crônica de óxido nítrico

Abstract

Lower Urinary Tract Symptoms (LUTS) represents one of the most commonly complaints in male. Several voiding disorders can be involved in the pathogenesis of LUTS. Hipogonadism is a common and underdiagnosed disease in the aging male, usually presenting simultaneously with LUTS. The objective of this study was to evaluate the cystometric effects of chronic tadalafil administration in castrated mice with nitric oxide cronic deficiency. The results of tadalafil administration were compared in castrated mice (hypogonadics) and after testosterone replacement (eugonadics). A total of 42 mice were randomized to six groups. Group 1 (L-NAME): L-name (60mg/kg), which is an oxide-nitric sintethase inhibitor, was administrated in drinking water. Group 2 (DTAD): L-name (60mg/kg) + diluent of tadalafil (mannitol and xantane gum). Group 3 (TAD): L-name + daily tadalafil (4mg/kg). Group 4 (ORQ): L-name + orchiectomy. Group 5(ORQ+TAD): L-name + orchiectomy + tadalafil. Group 6 (TEST): L-name + ORQ + TAD + testosterone undecanoate SC single dose (100mg/kg). During cystometry after thirty days, five parameters were measured: number of non-voiding contractions before first micturition (NVC) and micturition frequency (FM). Threshold pressure (TP) and basal pressure (BP) were expressed as mmHg, volume threshold (VT) was expressed as mL. Statistical analysis were held with GraphPad Prism®, using analysis of variance (ANOVA) and Tukey’s tests. Normality distribution was held with Kolmogorov-smirnov test. Level of significance was 5% (P<0.05). Mean and standard desviation (SD) were analysed. TAD (1.28±1.89), ORQ(0.16±0.40), and TEST (1.14±1.21) Groups had lower number of NVC compared to L-name (5.42±4.11) Group; ORQ + TAD(1,5±1,64) and ORQ had similar NVC (F=4,24, p=0,0042). Frequency of micturition: TAD (1.12±0.38) and ORQ (0.60±0.23) Groups had lower FM compared to L-name Group (2.27±0.68); ORQ + TAD (0.75±0.28) and ORQ (0.60±0.23) had similar FM; TEST Group (2,74±0,56) had higher FM compared to ORQ, TAD e ORQ + TAD Groups (F=28,82, p<0,0001). Threshold pressure: TAD (27.57±7.41) and ORQ (27±5.51) Groups had lower TP compared to L-name (41.43±10.86); ORQ + TAD (32.17±7.27) and ORQ (27±5.51) had similar TP; TEST (42.14±6.09) had higher TP compared to ORQ (27±5.51) and TAD (27.57±7.41) Groups (F=5,78, p=0,0006). Basal pressure: TAD (18.71±3.94) and ORQ (13±10.94) Groups had lower BP compared to L-name (31.14±4.56); ORQ(13±10.94) and ORQ+TAD (19.83±3.25) had similar BP; TEST(28±5.83) had higher BP compared to ORQ (F=5,72, p=0,0006). There were no statistical diferences in volume threshold between groups. There were no diferences between DTAD and L-name in any parameter. In conclusion, Tadalafil and castration were equally effective reducing detrusor overactivity and relaxing urethra in mice with nitric oxide chronic deficiency. Co-treatment of testosterone with tadalafil to castrated rats improves frequency of micturition, basal pressure and threshold pressure when compared to castration alone, suggesting an androgen-dependent alternative pathway in smooth muscle contraction e relaxation.