| PART IEstablishment of experimental subarachnoid hemorrhage model with endo-cerebrovascular perforationSubarachnoid hemorrhage (SAH) is the most common event in cerebral vessel accident, and cerebrovascular spasm (CVS) is the most severe complication of SAH. However, the pathophysiological mechanisms of SAH are not clear completely. The important reason is that there is no so good animal model to mimic the clinical event in experimental studies. Endovascular perforation model may mimic the SAH caused by the rupture of aneurysm in clinic.1, Materials and methods1) Experimental animal30 male Sprague-Dawley rats (300 to 350 g) were randomly assigned to two groups: sham (control) and SAH group, each containing 15 rats.2) Experimental model of SAHIn rats subjected to SAH, the right external carotid artery was isolated and severed, leaving a stump of approximately 3 to 4 mm. The internal carotid artery was clamped with a small vascular clip, and the common carotid artery was clamped with a small 5-mm aneurysm clip. The stump of the external carotid artery was reopened, and a 3.0 monofilament nylon suture was inserted up through the internal carotid artery for about 18 mm. A small resistance was usually felt, and the suture was then advanced 2 mm further to perforate the artery. The suture was immediately withdrawn, allowing reperfusion to produce SAH. Sham-operated rats underwent identical procedures except the suture was withdrawn just after the suture was advanced 5 mm.3) Cranial base examinationTwo hours or two days after SAH surgery, the brains were collected, SAH extension and volume were observed.4) Basilar artery diameter measurementTwo days after SAH induction, the diameter of the basilar artery was measured by the cerebrovascular casting method after perfused with India ink5) Water content in brainTwo days after SAH induction, the entire brain was taken out and weighed immediately after removal (wet weight) again after drying in an oven at 105℃ for 24 hours. Brain edema extent was indicated as the percentage of water content calculated as [(wet weight-dry weight)/wet weight × 100%].2, Results1) There was no any bleeding in sham rats, however, SAH extends from MCA-ACA bifurcation to the contralateral internal carotid artery and basilar artery in SAH group 2 hours and 2 days after SAH induction.2) The diameters of basilar arteries in SAH animals were smaller than those of sham control rats (195 ± 42μm vs. 286 ± 54 μm, p<0.01), indicating the present of cerebrovascular spasm in SAH animals.3) The brain water content in SAH animal was higher than that of sham animal (80.6±0.8% vs. 79.1±0.7%, p<0.05), suggesting that SAH animals suffer brain edema caused by cerebrovascular spasm.3, ConclusionsThe endovascular perforation technique presented here for establishing a non-craniotomy SAH model is reliable. This kind of animal model was characterized by CVS and brain edema two days after SAH induction.PART IIThe role of NADPH oxidase-derived superoxide in experimentalsubarachnoid hemorrhageAfter SAH, there is an excessive production of reactive oxygen, especially superoxide that is able to rapidly react with nitric oxide (NO). Subsequently, endothelium-dependent relaxation is impaired which is being considered as one of mechanisms contributing to vasospasm. Vasospasms were attenuated in transgenic mice that overexpress EC-SOD and Cu-Zn SOD following SAH. NADPH oxidase has been identified as a major source of superoxide in the vasculature. Racl is the cytosolic components of NADPH oxidase and serves as controlling key for NADPH oxidase activity. The role of Racl and NADPH oxidase in CVS after SAH is still unclear. Therefore, the present study aims at the mechanisms of Racl and NADPH oxidase-derived superoxide on CVS after SAH.1, Materials and Methods1) Rat SAH model was established as described in Part I2) Racl activity was measured by Western blot analysis according to the manufacture's instruction3) In situ measurement of superoxideDetermination of superoxide concentration was based on...
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