A specific one-sided left lung-dominated PF animal model was successfully established in rats. Experimental flowchart for inducing PF in rats' left lungs, the transplantation of HUMSCs, and the time course for various experiments in this study (A). BLM-induced PF in SD rats. Short Kaplan-Meier survival curves of 5 or 3 mg BLM injection indicated dose toxicity (B and C). A 2 mg BLM general intratracheal injection (n=3) showed inconsistent degrees of PF in all lobes after 49 days (D, H&E stains, right graphs % summary). There was no distinct change in appearance, and the PF was less than 50% (D). A one-sided left lung PF animal model was designed to create a stable, reproducible, consistent disease animal model. The results from the 2 mg/rat test group (n=7) in overall lung appearance and H&E staining demonstrated that a one-sided left lung PF animal model was successfully established in rats (E).