Experimental ischaemia-reperfusion injury induces vascular endothelial growth factor expression in the rat testis

Testicular torsion causes ischaemia-reperfusion (I-R) injury of testis and might lead to male infertility. Its injury initiates a pathophysiological cascade, including an activation of inflammatory cytokines and generation of nitric oxide and other reactive oxygen species. Vascular endothelial growth factor (VEGF) mediates angiogenesis and promotes endothelial cell survival. The aim of our study was to investigate the time course expression of VEGF, VEGF-receptor (R)1, VEGF-R2, nitric oxide synthases (NOS) in experimental I-R injury of rat testis. In torsion side testis, the expression of VEGF protein and mRNA significantly increased in a time-dependent manner (P < 0.001 and P < 0.001, respectively). Although the expression of VEGF-R1 mRNA was increased in a similar way (P < 0.001), VEGF-R2 mRNA expression was not detected. In immunohistochemistry, the increase in VEGF protein staining was observed in testicular vascular endothelial cells and germ cells at 24 h after reperfusion. Significant activation of inducible NOS and endothelial NOS was investigated at 12 and 24 h after reperfusion (P < 0.01 and P < 0.001, respectively). This is the first report to show the time course expression of VEGF in experimental I-R rat testis.