[Evaluation and optimization of cerebral vaospasm model with subarachnoid hemorrhage]

To determine biphasic changes of cerebral vasospasm (CVS) after subarachnoid hemorrhage (SAH) and its association with ischemic neurological injuries.

55 adult male New-Zealand rabbits weighing 2.0-2.5 kg were randomly divided into 2 groups: control and SAH groups(including 10 subgroups at different sacrificed time: 12 h, 24 h, 2 d, 3 d, 4 d, 5 d, 6 d, 7 d. 8 d, 9 d). The rabbits were induced into cisterna magna by withdraw of 0.5 mL cerebrospinal fluid followed with administration of 2 mL saline (control group) or fresh unheparinised autologous arterial blood (SAH group). The neurobehavioral scores were measured every day. The middle basilar artery and hippocampus were examined by optical microscope with HE stain, measuring coefficient of corrugation (CC) and survival number of hippocampal CA1 neurons. The neurological injury was assessed by injured hippocampal CA1 neurons and neurobehavioral scores.

Severe and moderate vasospasms were detected in basilar arteries of the rabbits in the SAH group. Compared with the control group, the CC of the rabbits of the SAH group decreased significantly at 12 h, 24 h, 2 d, 3 d, and 4 d (P < 0.05). The recovery on day 5 was temporary and the CC plunged again from day 6 (P < 0.05). No statistical significance was found in the numbers of survived hippocampal CA1 neurons between the two groups (P > 0.05). There was no correlation between hippocampal CA1 survival neurons and cerebrovasospasm progression.

Acute vasospasm occur from 12 h to day 4, which is followed by delayed vasospasm from day 5 to day 9. The hippocampal CA1, histopathological measurement is not suitable for evaluating brain injury after SAH.