| There are three parts in our study. The first part is to establish a steady model of cerebral vasospasm (CVS) after subarachnoid hemorrhage (SAH) in rabbits that produced by two-time blood injection of autologous arterial blood into the cisterna magna. The other two parts is respectively to discuss that the effect of cytochrome-c (Cyt-C) and platelet derived growth factor receptor-β(PDGFR-β) on the CVS after SAH in rabbits.Objectives:1. To investigate the longitudinal time course and morphological changes of basilar arteries (BA) after SAH in a rabbit model by two-time blood injection of autologous arterial blood into the cisterna magna.2. To observe the expression of Cyt-C in the basilar arteries after SAH in rabbits, and the effects of Cyt-C in apoptosis and the relations between the expression of Cyt-C and CVS.3. To observe the expression of PDGFR-βin the basilar arteries after SAH in rabbits, and discuss the effects of PDGFR-βon the CVS after SAH.Methods:1. Thirty-six New Zealand white rabbits were randomized to two experi- mental groups: control group and SAH groups (including 1d,3d,5d 7d,10d), each group have six rabbits. A steady model of cerebral vasospasm after SAH in rabbits was produced by two-time blood injection of autologous arterial blood into the cisterna magna. After perfusion-fixed, sectioned slices were examined by HE staining to observe the pathological changes of the BA, and the diameter of each basilar arterial lumen was measured to evaluate the degree of cerebral vasospasm. Another four rabbits were randomized to two groups: control group and SAH group(7d), and the ultrastructural changes of BA after SAH were examined by TEM.2. The grouping was similar to the first part. Furthermore, TUNEL and immunohistochemical technique were respectively used to observe the expressions of apoptotic cell and Cyt-C in the vessel walls of the basilar artery.3. The grouping was similar to the first part. Immunohistochemical technique was used to observe the expressions of PDGFR-βin the vessel walls of the basilar artery.Results: 1. The success rate of the CVS model was 80%. The basilar artery of SAH groups showed luminal narrowing obviously comparing to the control group(P<0.01), which was greatest in 1 day after SAH(P<0.01). And the narrowing was recovered, but at the 7 day it peaked again(P<0.01), and the narrowing at the 10 day was alleviated comparing to the 7 day. The results of TEM in SAH groups showed some ultrastructural changes in basiliar artery, including desquamation of partial endothelial cells, the tight junction's open, the expansion of endothelial gap, the distortion and disruption of internal elastic lamina, disordered arrangement in smooth muscle cells of cytoplasmic vacuolization, and the infiltration of abundant neutrophilic granulocyte and monocyte in adventitia.2. TUNEL revealed the apoptotic cell in the vessel wall began to appear in 1 day after SAH,then the apoptotic level was gradually increasing in the following days, and achieve peak value in 7 days after SAH. The expression of Cyt-C in SAH groups was rising comparing to control group, and it was the most significant expression in 7 days after SAH(P<0.01), and decreased 10 days after SAH, but it was still significantly higher than that in control group(P<0.05).3. The expression of PDGFR-βin control groups was negative, while the expression in SAH groups was positive, and it was the most significant expression in 5 and 7 days after SAH(P<0.01), and decreased 10 days after SAH, but it was still significantly higher than that in control group(P<0.05).Conclusions:1. The model in rabbits showed biphasic patterns to the luminal narrowing: acute constriction and delayed vasospasm phase. It was similar to humans of the time courses of vasospasm and morphological changes in the model, which was appropriate for investigating mechanism and therapeutic approaches in CVS after SAH.2. Apoptosis existed in the endothelial cells and smooth muscle cells of basilar artery in the model, the expression of Cyt-C was obvious rising and show the regular change in time course, which was the important factor inducing apoptosis. The expression of Cyt-C was in proportion to the extent of delayed cerebral vasospasm, and it may be important significance in the course of occurrence and development after CVS.3. The expression of PDGFR-βshowed the regular change in time course in the basiliar arteries after SAH, which suggested that PDGF-BB was important significance in the course of occurrence and development after CVS.
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