Unexpected presence of the neurotrophins NGF and BDNF and the neurotrophin receptor p75 in the tendon cells of the human Achilles tendon

Histol Histopathol. 2009 Jul;24(7):839-48. doi: 10.14670/HH-24.839.


Neurotrophins are substances that have been shown to be important in growth and remodelling phases in different types of tissue. There is no information concerning the possible occurrences of neurotrophins and their receptors in tendons. In this study, sections of both chronic painful (tendinosis) and pain-free (non-tendinosis) human Achilles tendons were immunohistochemically stained with antibodies against the neurotrophins NGF and BDNF, and their receptors TrkA, TrkB and p75. There were marked immunoreactions for NGF and BDNF in the tendon cells (tenocytes) of both tendinosis and non-tendinosis specimens. The tenocytes were also reactive for the receptor p75, but not for the receptors TrkA and TrkB. In addition, p75 immunoreactions were seen in nerve fascicles and in the walls of arterioles. This is the first study to identify neurotrophins in the tenocytes of human tendon. It is clear from this study that the local cells of tendons are sources of neurotrophins. The neurotrophins may play an important role in the tendon through their interaction with the receptor p75 in the tenocytes. These interactions may regulate tropic modulatory, and apoptotic effects. In conclusion, the observations show a new concept concerning production and function of neurotrophins, namely in the tenocytes of tendons.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Achilles Tendon / cytology*
  • Achilles Tendon / metabolism
  • Achilles Tendon / surgery
  • Adult
  • Brain-Derived Neurotrophic Factor / genetics
  • Brain-Derived Neurotrophic Factor / metabolism*
  • Chronic Disease
  • Female
  • Fluorescent Antibody Technique, Indirect
  • Fluorescent Dyes / metabolism
  • Humans
  • Immunohistochemistry
  • Male
  • Middle Aged
  • Nerve Growth Factor / genetics
  • Nerve Growth Factor / metabolism*
  • Receptor, Nerve Growth Factor / genetics
  • Receptor, Nerve Growth Factor / metabolism*
  • Rhodamines / metabolism
  • Tendinopathy / metabolism
  • Tendinopathy / pathology*
  • Tendinopathy / surgery
  • Young Adult


  • Brain-Derived Neurotrophic Factor
  • Fluorescent Dyes
  • Receptor, Nerve Growth Factor
  • Rhodamines
  • tetramethylrhodamine isothiocyanate
  • Nerve Growth Factor