Occurrence and evolution of T3 fibroblast nuclei in healing tendons from growing chicks

We applied immunocytochemical techniques including anti-triiodothyronine (T3) serum and microscopic analysis with colloid gold as the developer to identify the specific receptors of thyroid hormones located within the cell nucleus and between the heteroeuchromatin transition zone in 25 chicks. All chicks underwent tenotomy, followed by tenorrhaphy and immobilisation of the leg in plaster. There was a gradual decrease in the number of T3 receptors of collagen-forming fibroblasts as the tendons healed and their capacity to synthetize collagen diminished.