Reduction of Tendon Fibrosis Using Galectin-3 Inhibitors

Fibrosis is a complication of both tendon injuries and repairs. We aim to develop a mouse model to assess tendon fibrosis and to identify an antifibrotic agent capable of overcoming tendon fibrosis.Adult C57Bl/6 mice underwent a skin incision to expose the Achilles tendon, followed by 50% tendon injury and abrasion with sandpaper. Sham surgeries were conducted on contralateral hindlimbs. Histology and immunofluorescent staining for fibrotic markers (Col1, α-SMA) were used to confirm that the model induced tendon fibrosis. A second experiment was conducted to further examine the role of α-SMA in adhesion formation using α-SMA.mTmG mice (6-8 weeks old) (n=3) with the same injury model. The control group (tendon injury) was compared to the sham group, using the contralateral limb with skin incision only. A second experiment was conducted to further examine the role of α-SMA in adhesion formation using α-SMA.mTmG mice (6-8 weeks old) (n=3) with the same injury model. The control group (tendon injury) was compared to the sham group, using the contralateral limb with skin incision only. Lastly, α-SMA.mTmG mice were randomized to either condition 1. Tendon injury (control group) or 2. Tendon injury with Galectin-3 inhibitor (Gal3i) treatment at time of injury (treatment group).Histological analyses confirmed tendon thickening and collagen deposition after tendon injury and abrasion compared to control. Immunofluorescence showed higher levels of Col1 and α-SMA protein expression after injury compared to sham (*p<0.05). RT-qPCR also demonstrated increased gene expression of Col1 and α-SMA after injury compared to sham (*p<0.05). Gal3 protein expression also increased after injury and co-localized with α-SMA positive fibroblasts surrounding the fibrotic tendon. Gal3i treatment decreased collagen deposition and scarring observed in the treatment group (*p<0.05). Flow cytometry analysis further showed reduced numbers of profibrotic fibroblasts (CD26+) in the treatment compared to the control group (*p<0.05).Our study provides a reproducible and reliable model to investigate tendon fibrosis. Findings suggest the potential of Gal3i to overcome fibrosis resulting from tendon injuries.