Tendon induce endothelial cell proliferation and migration, and VEGF mRNA has been shown to be expressed at the site of tendon injuries along with collagen I mRNA. Bone morphogenetic proteins (BMPs) are a subgroup of TGF-β superfamily that can induce bone and cartilage formation as well as tissue differentiation, and BMP-12 specifically has been shown to influence formation and differentiation of tendon tissue and to promote fibrogenesis. In animal models, extensive studies have been conducted to investigate the effects of mechanical strain in the form of activity level on tendon injury and healing. While stretching can disrupt healing during the initial
Achilles tendon rupture can also contribute to injury. Fluoroquinolone antibiotics, famously ciprofloxacin, are known to increase the risk of tendon rupture, particularly Achilles. People who commonly fall victim to Achilles rupture or tear include recreational athletes, people of old age, individuals with previous Achilles tendon tears or ruptures, previous tendon injections or quinolone use, extreme changes in training intensity or activity level, and participation in a new activity. Most cases of Achilles tendon rupture are traumatic sports injuries. The average age of patients is 29–40 years with a male-to-female ratio of nearly 20:1. Direct steroid injections into the tendon have also been linked