Testicular torsion and reperfusion: Germ cell DNA damage and development.

This study is aimed to analyse the cross-link between cyclin D1, cdk-4, p21, PCNA and DNA damage during different periods of reperfusion following experimental torsion in rats. Thirty mature male Wistar rats (N = 6) were used. Following 4 hr from torsion induction, the reperfusion was induced. Animals were subdivided into groups, including 4 hr torsion-induced (T1), 1 hr post-reperfusion (T2), 2 hr post-reperfusion (T3), 4 hr post-reperfusion (T4) and 8 hr post-reperfusion (T5) groups. The seminiferous tubules differentiation (TDI) and spermatogenesis indices were evaluated. The expressions of cyclin D1, cdk-4, p21and PCNA were analysed using Reverse Transcriptase-PCR (RT-PCR). Moreover, the cyclin D1+ , cdk-4+ , p21+ and PCNA+ cell numbers/mm2 of tissue were assessed through immunohistochemical staining. The testicular DNA fragmentation was analysed using TUNEL assay and DNA ladder test. Observations demonstrated that reperfusion significantly increased (p < 0.05) up-regulated the expressions of cyclin D1, cdk-4 and PCNA. The animals in T5 group showed diminished expression of p21 and represented diminished DNA fragmentation versus T1 group. In conclusion, minimum 8 hr post-reperfusion is needed to re-initiate necessary expressions of cyclin D1, cdk-4 and PCNA to restore cell cycling machinery and ameliorate torsion-induced DNA damage.