Experiments were conducted in accordance with the guidelines approved by the University of California, San Francisco, Institutional Animal Care and Use Committee.
We used the elastase-induced intracranial aneurysms in 8 to 9 week old hypertensive mice as previously described.11 (link) In this model, two well-known clinical factors associated with human intracranial aneurysms—hypertension and the disruption of elastic lamina— were combined to induce intracranial aneurysm formation in mice. We performed a single stereotaxic injection of elastase into the cerebrospinal fluid at the right basal cistern. A volume of 2.5 μL of elastase solution (17 milli-units) was injected at a rate of 0.2 μL/min (Ultramicropump, World Precision Instruments). Hypertension was induced by a continuous subcutaneous infusion of angiotensin-II at 1000 ng/kg/min for three weeks via an implanted osmotic pump (Alzet pump, Durect).11 (link), 14 (link)
Systolic blood pressure was measured in mice before treatment, one week after elastase injection, and two weeks after elastase injection using the tail cuff method. After three weeks, we sacrificed the mice and perfused the animals with bromophenol blue dye. Two blinded observers assessed the formation of intracranial aneurysms by examining of Circle of Willis and its major branches under a dissecting microscope (10×). Intracranial aneurysms were operationally defined as a localized outward bulging of the vascular wall in the Circle of Willis or in its major primary branches, as previously described.10 (link), 11 (link) After inspecting the Circle of Willis, the whole brain samples were frozen in OCT for immunohistochemical staining.
We used the elastase-induced intracranial aneurysms in 8 to 9 week old hypertensive mice as previously described.11 (link) In this model, two well-known clinical factors associated with human intracranial aneurysms—hypertension and the disruption of elastic lamina— were combined to induce intracranial aneurysm formation in mice. We performed a single stereotaxic injection of elastase into the cerebrospinal fluid at the right basal cistern. A volume of 2.5 μL of elastase solution (17 milli-units) was injected at a rate of 0.2 μL/min (Ultramicropump, World Precision Instruments). Hypertension was induced by a continuous subcutaneous infusion of angiotensin-II at 1000 ng/kg/min for three weeks via an implanted osmotic pump (Alzet pump, Durect).11 (link), 14 (link)
Systolic blood pressure was measured in mice before treatment, one week after elastase injection, and two weeks after elastase injection using the tail cuff method. After three weeks, we sacrificed the mice and perfused the animals with bromophenol blue dye. Two blinded observers assessed the formation of intracranial aneurysms by examining of Circle of Willis and its major branches under a dissecting microscope (10×). Intracranial aneurysms were operationally defined as a localized outward bulging of the vascular wall in the Circle of Willis or in its major primary branches, as previously described.10 (link), 11 (link) After inspecting the Circle of Willis, the whole brain samples were frozen in OCT for immunohistochemical staining.
