Macrophages secrete a variety of bioactive substances, such as MMPs and cytokines, thereby playing an important role in lesion formation and progression.32 In the current study, we focused on MMP‐9, an important gelatinase, and generated Tg rabbits that overexpressed MMP‐9 in the macrophage lineage to examine whether increased MMP‐9 expression affects the initiation and progression of atherosclerosis. Here, MMP9 is linked to atherosclerosis.