Establishment of a medial arterial calcification model in C57BL/6J mice via arterial intimal injury.

BACKGROUND: Medial arterial calcification (MAC) increases vascular stiffness and reduces arterial compliance, often leading to serious systemic vascular diseases. However, research progress in this field has been limited by the lack of effective animal models. To address this gap and facilitate MAC research, this study established a novel experimental animal model of MAC in wild-type C57BL/6J mice and developed corresponding pathological grading standards. METHODS: To establish an optimal MAC modeling protocol, we systematically compared key parameters, including wire diameter, modeling duration, and combination with a vitamin D(3) (VD(3)) diet. The resulting model was then subjected to interventional treatments with various calcification inhibitors. For pathological assessment, a four-tier histopathological grading system was established to categorize calcification severity based on its extent and distribution. Tissue sections were analyzed by hematoxylin and eosin and Von Kossa staining. The expression of inflammatory factors and bone-related proteins was analyzed by immunohistochemistry (IHC), while macrophage markers (CD68, CD86) were further characterized by immunofluorescence (IF). RESULTS: The most effective method was identified as endothelial injury of the common carotid artery (CCA) using a 0.45 mm rough guide wire combined with a VD(3) diet for 3 months, achieving a 100% MAC incidence. Compared with those in the sham group, the CCAs of the mice in the experimental group were infiltrated with activated macrophages and inflammatory factors such as interleukin-1beta (IL-1β) and interleukin-6 (IL-6). Calcifcation inhibitors etidronate and SNF472 significantly prevented MAC occurrence, showing inhibition rates of 45.45% (P=0.006) and 50% (P=0.002), respectively, conpared to the VD(3) group (Fisher's exact test). CONCLUSIONS: This study not only establishes a MAC animal model by inducing injury to the CCA combined with a VD(3) diet but also introduces a corresponding pathological scoring system. Together, this model, coupled with this associated grading method, provides a valuable toolset for future basic medical research, drug screening, and investigations into the genetic mechanisms of MAC.