Rabbit Macrophage Colony-Stimulating Factor (M-CSF) is a cytokine that regulates the development, proliferation, and survival of monocytes and macrophages in rabbits (Oryctolagus cuniculus). M-CSF is produced by several cell types, including fibroblasts, endothelial cells, epithelial cells, and stromal cells, in response to tissue signals and inflammatory stimuli. Rabbit M-CSF binds to the colony-stimulating factor-1 receptor (CSF1R), a receptor tyrosine kinase expressed on monocytes and macrophage lineage cells, activating intracellular signaling pathways such as PI3K–AKT, ERK/MAPK, and JAK–STAT that promote differentiation and maintenance of macrophage populations. Through these mechanisms, M-CSF supports macrophage-mediated immune surveillance, phagocytosis, tissue homeostasis, and inflammatory responses. Because macrophages play a central role in host defense and immune regulation, M-CSF–mediated macrophage function is important for maintaining immune health and responding to infection or tissue injury in rabbits. In cell culture, recombinant rabbit M-CSF is commonly used to promote differentiation of rabbit monocytes or bone marrow–derived cells into macrophages and to support macrophage proliferation and functional assays in vitro. Rabbit M-CSF is also used in rabbit animal model research; for example, rabbit models of atherosclerosis are used to study macrophage-driven plaque formation and inflammatory processes involved in cardiovascular disease.