Which of the following is one of the three main exogenous attempts to influence bone remodeling?

• A. Growth factors (BMPs and PDGFs)
• B. Antibiotics
• C. Oxygen therapy
• D. Vitamin C supplementation

Answer: (A)

Growth factors such as BMPs and PDGFs act as external signals that directly drive bone formation and healing. BMPs (bone morphogenetic proteins) trigger mesenchymal stem cells to differentiate into osteoblasts, kick-starting new bone production. PDGFs (platelet-derived growth factors) attract osteoprogenitor cells and stimulate angiogenesis, supplying the blood vessels needed for healthy bone remodeling. Because these proteins are introduced from outside the body to enhance remodeling, they are considered exogenous approaches to influence bone healing.

Antibiotics help control infection but don’t modulate the remodeling process itself. Oxygen therapy can aid healing in poorly perfused tissues but isn’t a primary driver of remodeling signals. Vitamin C supports collagen synthesis, which is important for bone matrix, but it’s not a direct exogenous signaling treatment that orchestrates remodeling like growth factors do.