Effects of tadalafil on ischemia/reperfusion injury in rat brain

Tadalafil attenuates ischemic damage as well as reperfusion injury in the rat ovary

Objective:

Tadalafil is a selective phosphodiesterase type-5 inhibitor with a long half-life. It has a dual function in ischaemic and re-perfused tissues, i.e. vasodilatation and anti-oxidant effects. These features of tadalafil distinguish it from other anti-oxidants. We investigated the dual effect of tadalafil on ischaemia and reperfusion injury in the rat ovary.

Material and Methods:

We established five study groups. Group 1 (n=6): sham-operated; group 2 (n=6): torsion; group 3 (n=6): torsion and Tadalafil; group 4 (n=6): torsion/de-torsion; and group 5 (n=6): torsion/de-torsion and tadalafil. Ovarian samples were harvested from animals and evaluated in terms of histopathologic changes, tissue malondialdehyde (MDA) concentrations, lactate production, and plasma cyclic guanosine monophosphate (cGMP).

Results:

Follicular degeneration, oedema, haemorrhage, and inflammatory cells were significantly decreased in group 5 in comparison with group 4. Group 2 and group 3 were compared in terms of vascular congestion and haemorrhage; these parameters were significantly decreased in group 3. In addition, significantly decreased MDA and lactate concentrations were observed in group 5 in comparison with group 4. Increased cGMP concentrations were detected in group 3 and group 5.

Conclusion:

We conclude that tadalafil might be useful in protecting the ovary against ischaemia and reperfusion injury. In the evet of ovarian torsion, it will provide a greater therapeutic effect than only performing de-torsion of the ovary or using other anti-oxidant agents.

Phosphodiesterase 5 inhibition as a therapeutic target for ischemic stroke: A systematic review of preclinical studies

Phosphodiesterase 5 inhibitors (PDE5i), such as sildenafil (Viagra®) are widely used for erectile dysfunction and pulmonary hypertension. Preclinical studies suggest that PDE5i may improve functional outcome following ischemic stroke. In this systematic review we aimed to evaluate the effects of selective PDE5i in animal models of brain ischaemia. A systematic search in Medline, Embase, and The Cochrane Library was performed including studies in English assessing the effects of selective PDE5i. 32 publications were included describing outcome in 3646 animals. Neuroprotective effects of PDE5i were dependent on the NO-cGMP-PKG-pathway. These included reduced neuronal apoptosis (n=3 studies), oxidative stress (n=5), and neuroinflammation (n=2). PDE5i increased angiogenesis and elevated regional cerebral blood flow in the ischemic penumbra, and improved functional recovery. Some studies found that PDE5i treatment reduced lesion volume (n=9), others found no effect (n=9). Treatment was effective when administered within 24h post-ischemia, though treatment delayed to seven days improved outcome in one study. This review demonstrates both neuroprotective and neurorestorative effects of PDE5i in animal models of stroke, though the specific underlying signaling pathways relating to PDE5 inhibition and cGMP may remain serendipitous in some studies. There is currently limited evidence on the effects of selective PDE5i in human stroke patients, hence translation of preclinical results into clinical trials may be warranted.