TTF1 and pulmonary emphysema: The results of this study suggest that transplanted rAFMSCs can alleviate the lung injury caused by emphysema; they do so by integrating into lung tissues, potentially differentiating into AECII-like cells or inducing local regeneration of the lung alveolar epithelium, inhibiting AECII apoptosis, and elevating the levels of SPA, SPC, and TTF1 mRNAs and SPA and SPC proteins.