Therapeutic effect of caspase inhibitors in the prevention of apoptosis and reversal of chronic cerebral vasospasm.

One of the important histological changes in cerebral vasospasm after subarachnoid hemorrhage (SAH) is endothelial cell damage, which involves apoptosis. The current study was undertaken to determine whether anti-apoptosis therapy prevents apoptosis and reverses vasospasm in a dog SAH model. Twenty-three mongrel dogs of either sex, weighing 17-25 kg, were subjected to autologous arterial blood injection into the cisterna magna on day 0 and day 2, and sacrificed on day 7. Angiography was performed on day 0 before blood injection and on day 7 before sacrifice. Caspase-2 (Z-VDVAD-FMK, 10 microM) inhibitor, caspase-3 (Z-DEVD-FMK, 10 microM) inhibitor, or vehicle (DMSO) were injected intrathecally from day 2 to day 6. The effects of caspase inhibitors on apoptosis and vasospasm were evaluated by angiography and transmission electron microscopy. The residual diameter of the basilar artery on day 7 in SAH dogs without treatment was 53.4+/-5.5% of the day 0 diameter. Marked damage to the endothelial cells, including apoptotic like changes, was observed in these arteries. Both caspase inhibitors prevented apoptosis in the endothelial cells. Only caspase-3 inhibitor, however, had a near-significant effect on reducing 13.3% of angiographic vasospasm. Higher doses and early treatment, as well as other more potent apoptosis inhibitors, are recommended for future studies.