Gene Transfer Of ENOS Prevents Delayed Cerebral Vasospasm After Subarachnoid Hemorrhage In Rabbit

Objective: To investigate the effects of intravascular transfection of endothelial nitric oxide synthase gene on cerebral vasospasm after subarachnoid hemorrhage in rabbits,and explore the related mechanism through observating pathohistology and ultrastructural structure of cerebral arteries and hippocampus .Methods: Recombinant adenovirus vectors carrying endothelial nitric oxide synthase gene were established. Delayed cerebral vasospasm model after SAH was developed by injecting arterial blood twice through cisterna magna. Recombinant adenovirus was injected into carotid arterial to transfect the rabbits. Rabbits were randomly divided into four groups: normal group: no blood was injected into cistern; SAH group: injecting arterial blood twice through the cisterna magna after 0 and 48 hours; Ads group: injecting adenovirus without eNOS to the SAH rabbits ; AdeNOS group: injecting AdeNOS to the SAH rabbits. All animals were killed using perfusion-fixation on day 7 and the brain arteries and hippocampal tissue were removed for pathohistology and ultrastructural studies. Immunohistochemical method was used for detecting the expression of eNOS.Results: In double-hemorrhage modle,blood accumulated in the subarachnoid space,especially in the basal cistern . Immunohistochemistry confirmed that recombinant eNOS gene expressed mainly in the endothelium. Under microscope, the average diameters of the cerebral arterial in AdeNOS group were larger than SAH group and Ads group, and there was less vasospasm under electron microscope. SAH group had hippocampal tissue edema and widened perivascular space. The number of neurons of hippocampal CA1 region in AdeNOS group is more than SAH group. SAH group had marked pathological changes of neuron ultrastructure including cell swelling, structural integrity, nuclear condensation, mitochondrial vacuolization.Conclusions:This study suggests that continuous use of carotid artery infusion micro-pump method in rabbit cerebral artery make endothelial cells express recombinant endothelial nitric oxide synthase, leading to relieve delayed cerebral vasospasm following SAH and to improve blood supply of hippocampus.