Ultrastructural changes in vascular wall and vascular endothelial cells during early stage of acute mechanical cerebral vasospasm
- VernacularTitle:血管壁和血管内皮细胞超微结构在急性机械性脑血管痉挛早期的变化
- Author:
Jingjing LU
;
Shaodong ZHANG
;
Jing ZHAI
;
Hong WANG
- Publication Type:Journal Article
- From:
Chinese Journal of Tissue Engineering Research
2007;11(23):4646-4649
- CountryChina
- Language:Chinese
-
Abstract:
BACKGROUND:Cerebrovascular drag, occlusion and other mechanical stimulations inevitably occur during some craniocerebral operations, which cause acute mechanical cerebrovascular vasospasm. At present, the mechanism underlying the patho-physiology as well as the pathological prognosis of this acute mechanical vasospasm remains unclear.OBJECTIVE: To observe changes in the vascular diameter of the middle cerebral artery, cerebral blood flow (CBF), and ultrastructure of vascular wall and vascular endothelial cells, during the early stage (2 hours) of mechanical cerebral vasospasm in cats.DESIGN: Open experiment.SETTING: Department of Neurology, Beijing Tiantan Hospital, Capital Medical University; Beijing Institute of Neurosurgery.MATERIALS: Six healthy adult hybrid cats, of either gender, weighing from 2.5 to 3.5 kg, were provided by the China Medical Science Institute of Experimental Animals. Laser Doppler flowmetry (Periflux 5010, Sweden Perimed Company)was used.METHODS: This study was carried out in the Beijing Institute of Neurosurgery between August 2005 and March 2006. For all experimental surgical procedures, the cats were anesthetized by intraperitoneal injection of 200 g/L chloral hydrate, at 2 mL/kg, and then placed in a prone position. A median incision was made in the scalp and a square bone window, 8×10 mm, was opened at 1.5 cm posterior and 1.5 lateral to the anterior fontanel, after which the dura mater was pricked out. The fine detecting head of the Laser Doppler flowmetry was fixed to a region of the cerebral surfacewith no vessels or with only a few vessels. Subsequently, the cats were placed in lateral position. Under the surgical microscope, the right middle cerebral artery was exposed through a suborbital approach. Blunt apparatus was used to stimulate middle the middle cerebral artery repeatedly, at a frequency of 100 time/min within 30 minutes.The diameter of the middle cerebral artery was measured and a perfusion index of cortical brain tissue was monitored, separately, before and then at 0, 0.5, 1.0, 1.5, 2.0 hours after stimulation. Ultrastructural changes in the vascular wall and the vascular endothelial cells were observed during the early stage (2 hours) of mechanical cerebral vasospasm in cats.MAIN OUTCOME MEASURES: Diameter of the middle cerebral artery and the perfusion index of cortical brain tissue before and then at 0, 0.5, 1.0, 1.5, 2.0 hours after stimulation, as well as any ultrastructural changes in the vascular wall and endothelial cells 2 hours after stimulation.RESULTS: The results from six cats were were analyzed. ①The diameter of the middle cerebral artery was (0.617±0.129), (0.723±0.082), (0.840±0.084) mm 0, 0.5 and 1.0 hours after stimulation, respectively, which was significantly smaller than that before stimulation [(0.897±0.066) mm,t =4.74, 4.017, 1.299,P ＜ 0.01]. ② The perfusion index of cortical brain tissue was 67.8±18.5, 82.5±17.5, 89.8±24.0, 94.0±22.2 and 98.5±21.0 at 0, 0.5, 1.0,1.5 and 2.0 hours after stimulation, which was significantly lower than that before stimulation (159.2±23.5, t =4.716-7.469, P ＜ 0.01 ). ③ At the early stage of acute mechanical stimulation (2 hours) to middle cerebral artery, endothelial cell chromatin aggregated at the edge of the cells and achromocyte formed, but mitochondrial crista was unclear.CONCLUSION: Mechanical stimulation to the middle cerebral artery in cats can lead to cerebral vasospasm. Apoptosis of endothelial cells appears at the early stage of stimulation (2 hours). These results indicate that, in order to prevent against cerebral vasospasm, cerebrovascular mechanical stimulation should be as minimal as possible and that as few as possible craniocerebral operations should be performed.
