Pathological Changes Of Cerebral Vasospasm And The Expression Of Cell Apoptosis Related Factors JNK And AKT Following Subarachnoid Hemorrhage Of Rats

Objective:To study the histopathological changes and morphometric analysis of basilar artery in experimental subarachnoid hemorrhage (SAH) model, observe dynamically the pathological course and cell apoptosis following SAH, and observe the expression of P-JNK and P-AKT in the basilar arteries after cerebral vasospasm.Methods:Sprague-Dawley rats (n=60) were randomly divided into seven groups:control group and 1d,3d,5d,7d,11d and 14d group following SAH. The animal model was induced by modified two injections of arterial blood into the cisterna magna. Asilar arteries (BA) were chosed for morphometric analysis with light microscope and ultrastructureal changes with transmission electron microscopy; Apoptotic changes was detected by fluorescence microscope; P-AKT and P-JNK which in basal artery were detected by Western blot assay at different time points.Results:1. Light microscopic examination:Different degrees of cerebral vasospasm (CVS) were observed in each group following SAH. The basilar artery revealed luminal narrowing, reduction in diameter, thickness of wall, corrugation of the internal elastic lamina (IEL), and cellular proliferation were observed in the spastic BA as well. The degrees of cerebral vasospasm were especially severe in 3d,7d group(P<0.05).2. Transmission electron microscopic examinations showed apoptosis-like changes in endothelial cells in each group following SAH, such as beading of the cell membrane, condensation of the cytoplasm, condensation of peripheral nuclear chromatin, and cytoplasmic vacuolization. The morphological changes in endothelial were most severe and wide spread in 3d,7d group. Some endothelial cells and smooth muscle cells showed necrotic changes. Detachment of endothelial cells were widespread resulting in large areas of denudation from the IEL. Elastic layers appeared folds and fracture. Only in mild CVS, apoptosis and necrosis of endothelial cells were reduced in 11d group.3. Fluorescence microscope examination:endothelial cells and smooth muscle cells apoptosis which in basal arteries following SAH were observed, and nuclear becomed pyknotic and fluorescence stained deep.4.The Western blot tested the protein expression of P-JNK and P-AKT, which are compared with (3-actin to measure greyscale value. It showed that P-JNK expression in groups 3,7 days following SAH were significantly higher than that in control group (P< 0.05), while the increased P-AKT expression compared with controls was not statistically significant (P> 0.05); But the result showed that P-AKT expression in groups 11,14 days following SAH express significantly higher than that in control group (P<0.05), while the P-JNK controlled comparison was not statistically significant (P >0.05).Conclusion:The CVS following SAH coincides with the progress of apoptosis changes in endothelial cells and proliferation of cells in the vascular wall. It means that endothelial apoptosis and cellular proliferation might play an important role in the pathogenesis of vasospasm. And the JNK and the AKT are all expressing in CVS, but the expression level is different in different time points. So, the JNK and AKT signal pathway regulates apoptosis may be one of mechanism producing CVS.