The role of vascular endothelial growth factor in ischemia-reperfusion injury of testis

Abstract

OBJECTIVE: Testicular torsion causes ischemia-reperfusion injury of testis and leads to male factor infertility. Its injury initiates a pathophysiologic cascade. In recent studies, protective effect of VEGF has been shown in various forms of ischemia- reperfusion injury. However, no study has investigated the role of VEGF in testicular ischemia-reperfusion injury. The aim of our study was to investigate the time course expression of VEGF, VEGF-receptor (R)1, VEGF-R2, inducible and endothelial nitric oxide synthase (iNOS and eNOS) and to evaluate the effect of VEGF in ischemia-reperfusion injury of testis. DESIGN: Animal study. MATERIALS AND METHODS: Using 8-week-old SD rat, surgery for making unilateral experimental torsion was performed. After 1 hour of torsion, the testis was counter-rotated back to the natural position and reinserted into the scrotum. Bilateral castrations were performed in various time courses after reperfusion. Western bolt analysis and immunohistochemical evaluation were used to determine the activation of VEGF, iNOS, and eNOS. VEGF, VEGF-R1 and -R2 mRNAs were measured by reverse transcription PCR (RT-PCR) and quantitative real-time PCR (QRT-PCR) analysis. RESULTS: In torsion side testis, the expression of VEGF protein and mRNA significantly increased in a time dependent manner since 3 to 120 hour after reperfusion. Although the expression of VEGF-R1 mRNA was increased in a similar way, which of VEGF-R2 mRNA could not be detected. The increase of VEGF protein expression was observed in testicular vascular endothelial cells and seminiferous tubular endothelial cells. Significant activation of iNOS and eNOS were investigated at 12 and 24 hours after reperfusion. CONCLUSIONS: Our study is the first report in the literature to show the time course expression of VEGF in torsion caused ischemia-reperfusion injury testis. Further investigations, such as VEGF infusion study, may lead to a novel approach for the therapy of ischemia-reperfusion injury of the testis.