An Integrated Stroke Model with a Consistent Penumbra for the Assessment of Neuroprotective Interventions

Background/Aim: A longer period of vessel occlusion reduces the coefficient of variation of the infarct lesion size [‘infarct variation coefficient' (IVC)] due to a gradual expansion of the lesion within a limited territory defined by the vascular anatomy, but it increases the mortality rate. A crucial issue in the induction of experimental focal cerebral ischemia has been to achieve a low IVC value and a low mortality rate. We attempted to improve IVC and mortality using the 3-vessel occlusion model. Methods: We introduced a new, transtemporal fascia approach to expose the zygomatic arch, in which the fascia of the temporal muscle is cut and retracted dorsally together with the facial nerve and the vein en bloc. Results/Conclusion: The approach avoided traumatic venous bleeding around the zygomatic arch. We established a bloodless model of focal ischemia that can produce a consistent degree of reduction in the regional cerebral blood flow within the ischemic penumbra. The model, characterized by a 15-min ischemia, an IVC of 15-21%, and low mortality after ischemia, is expected to produce reliable preclinical evidence in the assessment of neuroprotective interventions for ischemic stroke. The entire procedure is presented in the online supplementary video (www. karger.com/doi/10.1159/000356048).