Microvascular Blood Flow is Altered After Repair of Testicular Torsion in the Rat

Abstract

Previous studies have shown that experimental testicular torsion with a duration of 1 hr. or longer causes irreversible damage to the rat testis, but that testicular blood flow values are normal 24 hrs. after repair of torsion. More acute evaluation of return blood flow after repair of torsion has not been performed and was the topic of this study. Laser-Doppler flowmetry was used to evaluate testicular microvascular blood flow before application of 1, 2, or 4 hr., 720 degrees torsion, during torsion, and at several time points after repair of torsion. Experiments were performed in both adult and prepubertal rats. Testicular torsion essentially eliminated blood flow in both adult and prepubertal testes. Considering all the flow data within each group after torsion repair, increasing time of torsion was associated with significantly less return blood flow in both adult and prepubertal animals. Interestingly, only the four hour torsion data was associated with reduced return flow in prepubertal animals while both two and four hour torsion were associated with poor return flow in adult animals. Vasomotion, or pulsatile microvascular flow, often seen before torsion in both adult and prepubertal animals, was never seen after torsion repair. Increasing times of torsion are associated with lower microvascular blood flow values during the hour following the relief of torsion. Vasomotion is eliminated by torsion during the period studied. Whether vasomotion returns is unknown, but altering this flow pattern might be involved in the mechanism of injury caused by acute torsion.