STAT3 and idiopathic pulmonary fibrosis: Furthermore, IHC staining results revealed that, compared with the model group, the nintedanib- and cyclophosphamide-treated groups showed reduced phosphorylation of JAK2/STAT3 protein in the IPF-LC mouse model, but the decreasing trend was more significant in the high-dose rhTβ4 groups (Figure 5E,F).