GAS6 and fibrosis: To evaluate the anti‐fibrotic effects of TP0903 in vivo, orthotopic mouse models of fibrosis TED were obtained via intra‐orbital injection of GAS6‐pretreated orbital fibroblast cell line (OF‐CL) cells, a fibroblast cell line established from OAT of patients with TED.[64] In this experiment, GAS6‐pretreated OF‐CL cells mixed with Matrigel were injected into the right orbital cavity (oculus dexter, OD) of mice to form the xenograft group, whereas an equal volume of PBS mixed with Matrigel was injected into the left orbital cavity (oculus sinister, OS) to serve as the control group (Figure 8a).