The Role Of Papaverine In Rabbit Cerebral Vasospasm After Subarachnoid Hemorrhage

OBJECTIVE:To investigate the role of papaverine in rabbit cerebral vasospasm after subarachnoid hemorrhageMETHODS:In this study, model of subarachnoid hemorrhage that is established by injecting autologous arterial blood to cisterna magna of unilateral carotid artery ligated rabbit.72 healthy adult rabbits were divided randomly into 4 groups, and each group was divided into 4 subgroups according to different time points pre-designed with 6 adult rabbits in each subgroup. Group A:sham-operated control group includes subgroup A1, A2, A3, which were raised respectively 24hour,72hours, 7days after sham operation; Group B:SAH control group, includes subgroup B1, B2, B3, which were raised respectively 24hours,72hours, 7days after the establishment of SAH model; Group C:SAH+PPV group, included subgroups of C1, C2, C3, which were raised respectively 24hours,72hours,7days after the establishment of SAH+PPV model; Group D:SAH+PPV gelfoam (sustained-release preparations) group, subgroups D1, D2, D3 were raised respectively 24hours,48hours, 7days after establishment of SAH+PPV gelfoam model. Rabbits of Group A, Group B, Group C and group D were decapitated and the brains were harvested according to different time points designed in advance. Coronal sections of brain tissue were taken post to the optic chiasm for respectively 1.4 and 2.0cm. The histopathological changes and ultrastructure of cerebral hippocampus CA1 subarea as well as the live neurons density were exmined by HE staining and the expressions of Bcl-2 and bax were studied by immunohistochemistry. All the experimental datas were analyzed by SPSS 17.0 software. RESULTS:HE-stained slides were observed under Optical microscope:vessel wall of basilar arteries in Group A are smooth, the structure of vessel walls was integral, and not thickened. Blood vessel diameters of Group B are obviously diminished, and endothelial cells of basilar arteries in Group B are manifested engorged. The internal elastic laminae ruffled, parts of the endothelial cells ecclasis, the smooth muscle cells degenerated. Blood vessel wall of Group C and D are little shrinked, and endothelial cells of vessels in these two groups are less engorgemented than Group B. The observation of hippocampus CA1 subarea and counting of survival neuron dense under microscope showed: Apoptosis of neurones in Group A are rarely observed; Apoptosis of neurones in larger number are observed in Group B. Group C and D showed obviously reduce of apoptosis of neurones compared to Group B of the same time points. Immunohistochemical staining of Bcl-2 and bax positive cells manifested:homogeneous diffuse brown color in cell plasm. (1)Positive stained cells of Bcl-2 are very rare in hippocampus in subgroups of Group A with shallow stain; Positive stained cells are abundant in subgroups of Group B,C and D. Positive stained cells in groups C and D are greater in number and deeply stained compared to the subgroups in Group B. (2) The same result can be found with respect to the expression of bax. Positive stained cells of bax are very rare in hippocampus in subgroups of Group A with shallow stain; Positive stained cells are abundant in subgroups of Group B,C and D. Positive stained cells in groups C and D are greater in number and deeply stained compared to the subgroups in Group B. After statistical analysis and through comparison among the groups and subgroups, we found the survival neuron dense and expression of Bcl-2 and bax significantly different.CONCLUSION:1,The expression of Bcl-2 and bax in neuronal cells is enhanced by subarachnoid hemorrhage.2,Papaverion paly an vasodilative role in cerebral vasospasm after subarachnoid hemorrhage. It enhance the expression of Bcl-2 and inhibit the expression of bax and play a role of anti-apoptosis.3,Papaverion sustained-release preparation play an significant vasodilative role in cerebral vasospasm after subarachnoid hemorrhage, but gelfoam is still not the ideal carrier.