Establishment of transparent cranial window after cerebral subarachnoid hemorrhage and studying of cerebral cortical blood flow in rats

Objective Establishment of a transparent cranial window model of subarachnoid hemorrhage in rats for 7 days of continuous monitoring of cortical blood flow after subarachnoid hemorrhage Methods Thirty SD male rats were randomly divided into normal control group (n=10), saline group (n=10)and blood injection group (n=10). The transcranial subarachnoid hemorrhage transparent cranial window observation model was established by injecting autologous non-anticoagulation tail artery blood 0.3 ml twice in the occipital large pool and using a transparent flexible material made of silicon-based polydimethylsiloxane. Seven-day dynamic changes in cerebral cortical blood flow within the cranial window were monitored by laser speckle imaging. Results The imaging of 27 rats were clear; the blood flow velocity of the cortex decreased after SAH, which was statistically different from the control group and the saline group (P<0.01), and the blood flow on the 3rd, 5th, and 7th day after SAH. The percentage speeds were (83.20±4.16)%, (64.00±3.05)%, (75.70±3.79)%, and the 5 d was statistically different from the 3rd and 7 d (P<0.01); cortical blood perfusion after SAH The amount decreased, which was statistically different from the control group and the saline group (P<0.05). The percentage blood perfusion of the cortex on the 3rd, 5th, and 7th after SAH was (75.40±4.18)%, (31.80±5.34)%, (68.90±6.31)%, the 5th was statistically different from the 3rd and 7 d (P<0.01). Conclusion Through the use of a new flexible transparent material to establish a subarachnoid hemorrhage transparent cranial window imaging model, combined with laser speckle imaging technology can clearly detect the decline of cortical blood flow velocity and cortical blood perfusion in rats after subarachnoid hemorrhage 5 d is the peak of decline, and recovery begins on the 7th day, providing a new method for studying the pathophysiological changes in the acute and subacute phases after subarachnoid hemorrhage. Key words: Subarachnoid hemorrhage; Transparent cranial window imaging; Cerebral cortex blood flow; Laser speckle imaging technique; Rat