Study of cerebral aneurysms in a modified rat model: from real-time imaging to histological analysis

Cerebral aneurysm (CA) is a life-threatening condition with a pathogenesis that remains unclear. Previous hypotheses have primarily been based on in vitro examinations of animal models. Therefore, we attempted to observe CA in living rats and to establish a multi-level evaluation system. The rat model was produced by deoxycorticosterone-acetate (DOCA; Sigma Aldrich, St. Louis, MO, USA) induced hypertension and a single injection of elastase into the basal cistern. The animals were assessed 35 days later. At the endpoint, we induced well-developed CA in 41.7% of the surviving rats. Using synchrotron radiation angiography (SRA), we observed the experimental aneurysms and their surrounding arteries dynamically in the living model. Further anatomical and histological analyses demonstrated the typical degenerative changes of the mural structure and a major infiltration of macrophages into the aneurysmal wall. In conclusion, we visualised well-developed experimental CA in living rats using SRA and demonstrated the associated degenerative histological changes and macrophage involvement; thus, we have provided an effective model for the study of dynamic multi-level changes associated with CA in a rat model.