Other studies have explored the role of anti-inflammatory cytokines, such as interleukin-4 (IL-4) and interleukin-10 (IL-10)11–13, and the potential role of growth factors, including growth differentiation factor 5 (GDF5)14 in the alleviation of IDD through promotion of matrix synthesis, cell proliferation and differentiation, reduced cell apoptosis, and tissue regeneration. The gene discussed is GDF5; the disease is intervertebral disk degenerative disorder.