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Asian Journal of Andrology (2013) 15, 269–274 doi:10.1038/aja.2012.112; published online 31 December 2012
Role of TNF-related apoptosis-inducing ligand (TRAIL) in the pathogenesis of varicocele-induced testicular dysfunction
Orcun Celik1, Omer Kutlu2, Merih Tekcan3, Ciler Celik-Ozenci3 and Ismail T Koksal1
1 Department of Urology, Faculty of Medicine, Akdeniz University, Antalya 07070, Turkey
2 Department of Urology, Faculty of Medicine, Karadeniz Technical University, Trabzon 61080, Turkey
3 Department of Histology and Embryology, Faculty of Medicine, Akdeniz University, Antalya 07070, Turkey
Correspondence: Dr IT Koksal, (tkoksal@akdeniz.edu.tr)
Received 11 June 2012; Revised 31 July 2012; Accepted 1 September 2012
Advance online publication 31 December 2012
| Abstract |
The higher frequency of varicocele in men with infertility has drawn attention and resulted in increased research at the molecular level towards treatments. The aim of this study was to investigate the role of tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) and its receptors in varicocele-induced testicular dysfunction in an experimental rat model. The rats were divided into three groups: control, sham and varicocele. Varicoceles in rats were induced by partial ligation of the left renal vein and left testes. The rats were analyzed 13 weeks after surgery. The degree of DNA fragmentation within cells in the testis was determined using terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling (TUNEL) assay. Tubule degeneration was evaluated using the Johnsen score. The expression of TRAIL and its receptors was detected by immunohistochemical and Western blotting techniques. The apoptotic index, Johnsen score and the expression of TRAIL and TRAIL receptors were examined. The data are presented as the mean±s.d. and were analyzed using computer software. The Kruskal–Wallis and Dunn's multiple comparison tests were used in the statistical analyses. The germ cell apoptotic index was increased in rats with varicoceles when compared with the sham and control groups (P=0.0031). The Johnsen score was significantly decreased in the varicocele group when compared with the sham and control groups (P<0.0001). Immunohistochemical and Western blotting analyses showed that after varicocele induction, the expression of TRAIL-R1 and TRAIL-R4 in germ cells was increased and the expression of TRAIL-R2 was decreased. There are no significant differences among the groups in terms of TRAIL and TRAIL-R3 receptor expression. The results of this study indicate that TRAIL and its receptors may have a potential role in the pathogenesis of varicocele-induced testicular dysfunction.
Keywords: apoptosis; infertility; testis; TNF-related apoptosis inducing ligand (TRAIL); varicocele |
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