Thyroid hormones increase collagen I and cartilage oligomeric matrix protein (COMP) expression in vitro human tenocytes

BACKGROUND: we previously demonstrated the presence of high levels of thyroid hormones (THs) receptors isoforms in healthy tendons, their protective action during tenocyte apoptosis, and the capability to enhance tenocyte proliferation in vitro. In the present study we tested the ability of THs to influence ECM protein tenocyte secretion in an in vitro system. METHODS: primary tenocyte-like cells were cultivated for 1, 7 and 14 days in the presence of T3 or T4 individually or in combination with ascorbic acid (AA). RESULTS: THs (T3 or T4) in synergism with AA increase significantly the total collagen production after 14 days. THs in synergism with AA increase significantly the expression of collagen I,biglycan and COMP, after some days. CONCLUSION: THs play a role on the extra cellular matrix of tendons, enhancing in vitro the production of several proteins such as collagen I, biglycan and COMP. THs receptors are active on human tenocytes, and can play a role in tendon ailments.