Fig. 1

PFD combined with UC-MSCs improves lung function in IPF mice more effectively. (a) Illustration of the study design. Day 1: the control group received 50 µL of saline intratracheally, the remaining mice were administered intratracheally with the same volume of bleomycin (3 mg/kg) to induce pulmonary fibrosis. From day 4 to day 21, mice in the PFD group and the PFD combined cell therapy groups received PFD (100 mg/kg, two times/day) via intraperitoneal injection. Mice in the remaining groups received intraperitoneal injections of an equivalent volume of saline. Mice treated with UC-MSCs (200 µL per animal) received one time different concentrations (low UC-MSCs: 0.5 × 10⁶ cells per animal, medium UC-MSCs: 1.0 × 10⁶ cells per animal, high UC-MSCs: 2.0 × 10⁶ cells per animal) via tail vein on day 4. Mice in the remaining groups received the same volume of saline once by tail vein on day 4. (b) The P4 UC-MSCs morphology (40 × ). (c) Flow cytometric analysis of UC-MSCs after the fourth passage of culture. (d) Lung function after UC-MSCs injection with or without PFD (n = 6). f: respiratory rate, Penh: enhanced pause, Cdyn: dynamic lung compliance, MV: minute volume, FVC: forced ventilation capacity, TV: tidal volume, Ti: inspiratory time, Te: expiratory time, PEF: peak expiratory flow, PIF: peak inspiratory flow, EF50: expiratory flow 50. Data were expressed as means ± SD. The significant difference was analyzed by the letter-based method. Groups that share at least one common letter were considered not significantly different from each other, while groups with completely different letters were considered significantly different. (P < 0.05). Abbreviations: PFD: pirfenidone. PFD + Low: PFD + Low UC-MSCs. PFD + Medium: PFD + Medium UC-MSCs. PFD + High: PFD + High UC-MSCs. Low: Low UC-MSCs. Medium: Medium UC-MSCs. High: High UC-MSCs.