Nitric oxide is a small free radical generated by family of enzymes, the nitric oxide synthases. Following injury to a tendon, nitric oxide is induced by all three isoforms of nitric oxide synthase, the enzyme that makes nitric oxide. Nitric oxide synthase activity is also upregulated in tendinopathy. In animal models when nitric oxide synthase activity is inhibited by competitive inhibitors of nitric oxide synthase, tendon healing is reduced. When additional nitric oxide is added, tendon healing is enhanced. In humans in three randomized clinical trials, we have shown that nitric oxide delivered via a transdermal patch enhances the subjective and objective recovery of patients with tennis elbow, Achilles tendinosis and supraspinatus tendinosis.
- nitric oxide
- tendon healing