FTY720 inhibits germ cell apoptosis in testicular torsion/detorsion

Background: Testicular torsion/detorsion (T/D) can induce germ cells apoptosis, which may lead to impairment of spermatogenesis. FTY720, an agonist of the sphingosine-1-phosphate receptor 1 (S1PR1), inhibits apoptosis in ischemic stroke. We examined whether FTY720 could mitigate germ cell apoptosis in testicular T/D rats. Materials and Methods: Adult male Sprague-Dawley rats were allocated to receive testicular T/D (the T/D group), T/D plus FTY720 (the T/D-FTY group), or T/D plus FTY720 plus the potent S1PR1 antagonist VPC23019 (the T/D-FTY-VPC group; n = 6 in each group). Sham control groups were run simultaneously. At 24 h after detorsion, rats were euthanized. Results: Our data revealed that, in the ipsilateral twisted testes, sperm counts and expression of the S1PR1 of the T/D and the T/D-FTY-VPC groups were significantly lower than those of the T/D-FTY group (all P < 0.001). In contrast, signals of apoptotic cells stained by terminal deoxynucleotidyl transferase dUTP nick end labeling and the proapoptotic protein cleaved caspase-3 of the T/D, and the T/D-FTY-VPC groups were significantly stronger than those of the T/D-FTY group. Moreover, the terminal deoxynucleotidyl transferase dUTP nick end labeling signals mainly localized to germ cells. Conclusions: FTY720 could mitigate testicular T/D-induced germ cell apoptosis, and the mechanisms may involve the S1PR1. (C) 2016 Elsevier Inc. All rights reserved.