Effect of allopurinol and oxypurinol treatment on apoptosis in an experimental testicular torsion model.

BACKGROUND: The aim of this study was to investigate whether allopurinol and oxypurinol treatment could mitigate oxidative stress and germ cell apoptosis in testicular ischemia-reperfusion (IR) injury. METHODS: Thirty-two male rats were divided into four groups: Group 1 (Sham-Operated, n=8), in which the testicle was exposed but torsion was not performed; Group 2 (IR + Saline, n=8), in which torsion/detorsion was applied to the left testicle and 1 mL of normal saline was administered; Group 3 (IR + Allopurinol, n=8), in which torsion/detorsion was applied to the left testicle and 50 mg/kg allopurinol was administered; and Group 4 (IR + Oxypurinol, n=8), in which torsion/detorsion was applied to the left testicle and 50 mg/kg oxypurinol was administered. On postoperative day 28, left testicular tissue samples were collected, and total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI) levels were measured. Additionally, the gene expression levels of Bax, B-cell lymphoma 2 (Bcl-2), endothelial nitric oxide synthase (eNOS), and vascular endothelial growth factor A (VEGF-A) were analyzed. RESULTS: Allopurinol and oxypurinol significantly decreased OSI levels (p<0.001). Oxypurinol was found to be significantly more effective in reducing oxidative stress (p<0.001). Both allopurinol and oxypurinol significantly reduced Bax gene expression levels (p<0.001). Treatment with allopurinol (p=0.009) and oxypurinol (p=0.001) significantly increased Bcl-2 levels. Additionally, both agents significantly reduced the apoptosis index (p<0.001). Allopurinol (p1=0.007, p2<0.001) and oxypurinol (p1,2<0.001) treatments significantly increased eNOS and VEGF-A gene expression levels. CONCLUSION: Allopurinol and oxypurinol reduce oxidative stress in the testis following IR injury, with oxypurinol demonstrating a greater antioxidant effect. Both treatments also reduce apoptosis by contributing positively to the eNOS and VEGF-A-mediated repair processes. Therefore, allopurinol and oxypurinol may serve as potential therapeutic agents for clinical application in testicular torsion.