PROTECTION BY ILOPROST (STABLE ANALOG OF PROSTACYCLIN) OF ENDOTHELIALDAMAGE DUE TO CHRONIC VASOSPASM IN DOGS - AN ELECTRON-MICROSCOPE STUDY

The resolution of cerebral vasospasm and protection of endothelial dam age by Iloprost was evaluated with multicisternal injections. Sixteen adult mongrel dogs (18-20 kg) were assigned to one of three experiment al groups. All animals received a total amount of 15 ml fresh unhepari nized arterial blood via three injections into the cisterna magna. Sel ective vertebral angiography was performed on day 0 and subsequently b lood injections were performed on the 2nd and 3rd days after the first injection. On the 7th day angiography was reperformed to determine th e chronic vasospasm. The first group (5 dogs) was the control group an d received intrathecal saline which was equal to the amount of saline in which lloprost was diluted. The second group (5 dogs) did not recei ve any treatment until the 7th day. The third group (6 dogs) received lloprost intrathecally (total 10 mu g kg(-1)). In the first two groups angiographic vasospasm was prominent. For the second group intraarter ial Iloprost was given on the 7th day in order to evaluate its acute e ffect. However there was no evidence of resolution of vasospasm. In th e third group, resolution of vasospasm was verified on angiograms. Ele ctron microscope studies of basilar arteries of the first two groups r evealed degenerative changes of the endothelial cells which were separ ated from each other and the elastic lamina was irregularly arranged. In the intrathecal Iloprost-treated group there was little thickening in the elastic lamina and the endothelial cells were almost normal in structure. These results can be considered as the evidence of the prop hylactic effect of Iloprost given by the intrathecal route in the prev ention of chronic cerebral vasospasm.