The effect of phosphodiesterase inhibitor tadalafil on vasospasm following subarachnoid hemorrhage in an experimental rabbit model.

Background: despite the years of study on it, cerebral vasospasm following subarachnoid hemorrhage is still an important cause of mortality and morbidity. The presented study was undertaken to show whether phosphodiesterase inhibitor tadalafil can attenuate the vasospasm process following subarachnoid bleeding.

Method: in this study, 20 male New Zealand White rabbits weighing 2,500-3,000 g were randomly assigned to four groups. Animals in group 1 were controls. In group 2, animals were given oral tadalafil at 12, 24 and 36 h and SAH was not induced. SAH induced animals in group 3 did not receive any medication. In group 4, animals received tadalafil at 12, 24 and 36 h after SAH induction. All animals were sacrificed via exsanguination at 48 h after induction of SAH. Brains and brainstems with overlying basilar arteries were removed and stored in fixative at +4°C overnight. Basilar arteries were sectioned from four separate zones, and four sections were obtained from each rabbit. Basilar artery luminal section areas were measured by using SPOT for Windows version 4.1. Statistical comparisons were performed using Kruskal Wallis and ANOVA tests.

Findings: the SAH induced group which had been treated with tadalafil had significantly greater basilar artery luminal area than the untreated group (p < 0.05). There was no significant difference between control group and non-SAH induced group in terms of luminal areas.

Conclusion: tadalafil has a potentially preventive effect in treatment of cerebral vasospasm following subarachnoid bleeding.