CLINICS 2011;66(1):137-142 BASIC RESEARCH DOI:10.1590/S1807-59322011000100024 Protective effect of sildenafil citrate on contralateral testis injury after unilateral testicular torsion/detorsion Hamit Yıldız,I Ali Said Durmus,II Halil S¸ ims¸ek,III Mine YamanIV I Department of Obstetrics and Gynecology, Faculty of Veterinary Medicine, Fırat University, 23119 Elazı g˘, Turkey. II Department of Surgery, Faculty of Veterinary Medicine, University of Firat, 23119, Elazig-Turkey. II Sanitary Services Vocational School of Higher Education, University of Bing o¨l, 12000 Bingo¨ l, Turkey. IV Department of Histology, Faculty of Veterinary Medicine, University of Firat, 23119, Elazig-Turkey. OBJECTIVES: This study was designed to investigate prevention of contralateral testicular injury with sildenafil citrate after unilateral testicular torsion/detorsion. METHODS: Thirty-seven adult male rats were divided into four groups: sham operated (group 1, n = 7), torsion/ detorsion + saline (group 2, n = 10), torsion/detorsion + 0.7 mg of sildenafil citrate (group 3, n = 10) and torsion/ detorsion + 1.4 mg of sildenafil citrate (group 4, n = 10). Unilateral testicular torsion was created by rotating the right testis 720˚ in a clockwise direction for 2 h in other groups, except for group 1, which was served as sham group. After torsion (2 h) and detorsion (2 h) periods, rats were killed. RESULTS: The level of reduced glutathion (GSH) (p,0.05) and the activities of catalase (p,0.01) and glutathione peroxidase (p,0.05) in the contralateral testis from group 2 were significantly lower and nitric oxide (NO) (p,0.05) level in the contralateral testis were significantly higher than those of group 1. Administration of low-dose sildenafil citrate (group 3) prevented the increases in malondialdehyde and NO levels and decreases in glutathione peroxidase activities and GSH values induced by testicular torsion. However, administration of high-dose sildenafil citrate (group 4) had no effect on these testicular parameters (p.0.05). Histopathological changes were detected in groups 2, 3 and 4. CONCLUSION: These results suggest that biochemically and histologically torsion/detorsion injury occurs in the contralateral testis following 2-h torsion and 2-h detorsion and that administration of low-dose sildenafil citrate before detorsion prevents ischemia/reperfusion cellular damage in testicular tissue. KEYWORDS: Testicular torsion; Ischemia-reperfusion damage; Sildenafil citrate; Rat. Yıldız H, Durmus AS, S¸ims¸ek H, Yaman M. Protective effect of sildenafil citrate on contralateral testis injury after unilateral testicular torsion/ detorsion. Clinics. 2011;66(1):137-142. Received for publicaiton on August 12, 2010; First review completed on September 29, 2010; Accepted for publication on October 10, 2010 E-mail: hamityildiz@firat.edu.tr Tel.: 90 424 237 00 00 / 3854 INTRODUCTION Testicular torsion is the most common cause of testicle loss in newborns, children and adolescent boys.1 Although experimental and clinical studies have demonstrated that the contralateral (nontorted) testis is injured after unilateral testicular torsion (UTT),2,3 some studies have shown that this phenomenon is not always observed.4,5 The period of ischemia and reperfusion is an important factor for detrimental effects on the contralateral testis. Several studies have shown that testicular tissue damage is related to the degree of rotation of the testicle, reperfusion time and the duration of torsion.6 Testicular ischemia induces germ cell Copyright 2011 CLINICS – This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http:// creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non- commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. death, which is attributed mainly to a reduction in oxygen supply relative to metabolic demands, depletion of the stored cellular energy and accumulation of toxic metabo- lites. The reperfusion phase may significantly exacerbate ischemia-induced germ cell injury via the formation of reactive oxygen and nitrogen species.7 Germ cell apoptosis in the contralateral testis increased significantly after 2, 3 and 24 h of ischemia and showed direct, time-related correlation with the duration of ischemia.8 On the whole, at least 4 h of 720˚ unilateral testicular torsion causes enough testicular tissue injury in both testis in rats.2 Yazıhan et al.3 reported that 2 h of 720˚ unilateral testicular torsion and 4 h of detorsion time caused significant biochemical and histological changes in both ipsilateral and contralateral testes. However, some studies previously9,10 showed that 2- h torsion and 2-h detorsion had an adverse effect on the contralateral testis. Although sildenafil citrate has been developed for erectile dysfunction, it now has other medical indications (disease 137