Which cells are primarily involved in initiating granulation tissue formation?

The primary involvement of fibroblasts in initiating granulation tissue formation is integral to the healing process following injury. Fibroblasts are specialized cells that play a critical role in the synthesis of extracellular matrix and collagen, which are essential components of granulation tissue.

When tissue is injured, fibroblasts migrate to the site and begin to proliferate. They are responsible for producing the collagen fibers that provide structural support and strength to the newly formed tissue. Additionally, fibroblasts secrete growth factors and cytokines that are crucial for attracting other cells to the area, promoting angiogenesis (the formation of new blood vessels), and ultimately facilitating the healing process.

While neutrophils and macrophages are also important during the inflammatory phase of healing, their roles focus on clearing debris and pathogens rather than the formation of granulation tissue itself. Endothelial cells do contribute to the formation of granulation tissue by forming new blood vessels, but they are not the primary initiators of tissue formation. Therefore, the involvement of fibroblasts is crucial in the formation and maturation of granulation tissue, making this the correct answer.