TGFB1 and disease of the tendon: Nevertheless, Xu et al. reported that TGFβ is necessary for tendon-derived stem cell (TSC) exosomes to induce MSCs to secrete type I collagen [90]; this was confirmed by a rat Achilles collagenase-indued tendinopathy model, which reported a more ordered collagen fibre arrangement and increased ultimate stress and maximum loading [34].