STAT3 and intervertebral disk degenerative disorder: Increased expression of IL-6 and activation of STAT3 (pSTAT3) has been observed in human patients with disc degeneration and disc herniation [38, 61]; circulating IL-6 is positively associated with radiographic osteoarthritis and loss of knee cartilage loss in humans [62]; and IL-6/STAT3 signaling is activated in trauma-induced osteoarthritis [63, 64].