Involvement of Cerebral Blood Flow on Neurological and Behavioral Functions after Subarachnoid Hemorrhage in Mice

Objective: Cerebral Blood Flow (CBF) change after Subarachnoid Hemorrhage (SAH) is strongly associated with brain injuries such as early brain injury and delayed cerebral ischemia. We evaluated the correlation between CBF using Laser Speckle Flow Imaging (LSFI) after SAH and neurological findings in the sub-acute phase. Method: An SAH was induced by endovascular perforation in male mice. CBF was quantitatively measured by using LSFI at six time points, immediately to 14 days after SAH induction. Behavior tests and survival rate were evaluated. The mice were divided into recovery and hypo-perfusion groups according to their CBF at 1 day after the procedure. Result: Forty mice were included in this study. Five mice (20%) were included in the hypo-perfusion group, and the remaining 20 (80%) mice were classified as the recovery group. The decrease of CBF in the recovery group was observed until 1 day after the procedure. However, the decrease of CBF in the hypo-perfusion group was prolonged until 7 days after the procedure. Neurological findings and survival rates in the hypo-perfusion group were significantly worse than those in the recovery group. The low alternation cases (< 50%) in the Y maze test in the recovery group (n = 5) had significantly lower CBF at 1 day after the procedure. Conclusion: Low blood flow at 1 day after SAH was associated with worse survival rate, neurological findings, and memory disturbance. Early improvement in CBF may be associated with an improved prognosis after SAH.