It has been recently reported that chronic vasospasm is caused by free radical injury after subarachnoid hemorrhage. Since alpha-tocopherol is one of the free radical scavengers, effect of intrathecal use of alpha-tocopherol was evaluated experimentaly.
Twenty adult dogs were used for these study. These dogs were equally divided into subarachnoid hemorrhage (SAH) group and SAH+ alpha-tocopherol group. SAH was made by intrathecal injection of 5 ml of auto-blood with 2 ml of normal sailine into cisterna magna in SAH group. (10 dogs). Two ml (100mg) of alpha-tocopherol was injected instead of the same amount of normal sailine in SAH+ alphatocopherol group. (10 dogs).
1) Diameter of basilar artery (BA) and posterior cerebral artery (PCA) was measured on angiogram which was taken before and 24 hours after SAH. BA and PCA in SAH+ alpha-tocopherol group were dilatated 24 hours after SAH compared with these before, while these arteries in SAH group became narrower. (P<0.01)
2) Animal's condition was examined after SAH as below.
stage 0: the same as the condition before SAH.
stage 1: moving actively.
stage 2: sitting only.
stage 3: lying down. In SAH+ alpha-tocopherol group 7 dogs were in stage 1 and 3 dogs were in stage 2 after SAH, while 6 animals were in stage 3, 3 in stage 2, 1 in stage 1 in SAH group.
3) Every cases were examined pathologically, which showed endotherial degeneration and edema, constriction of internal lamina, and edema and vascular degeneration of the media in SAH group. But only mild constriction of internal lamina was found in SAH+ alpha-tocopherol group. Therefore intrathecal use of alpha-tocopherol seems to have preventive effect of chronic vasospasm experimentally.
