Fig. 1: Melatonin increased survival and improved pulmonary epithelial function in response to bleomycin.

Mice were intratracheally treated with PBS or bleomycin (BLM) with or without melatonin (MLN), (PBS group: n = 25, BLM group: n = 26, BLM + MLN group: n = 25). a Survival plots of mice in the PBS, BLM, and BLM + MLN groups. *P < 0.05. b Mice were intraperitoneally injected with Evans blue solution (1 ml/kg 3% Evans blue solution in PBS) for 30 min before euthanization. The amount of Evans blue was measured in the whole lungs of mice in the PBS, BLM, and BLM + MLN groups and normalized to the Evans blue concentration in methanamide to generate an Evans blue index. n = 3; *P < 0.05. c H&E staining of representative lung sections from mice in the PBS, BLM, and BLM + MLN groups. Scale bars, 50 μm. d The mRNA expression of inflammatory factors (IL1β, IL6, and TNFα). n = 4; *P < 0.05, **P < 0.01. e The Immunohistochemical assay of E-cadherin in lung samples from mice in the PBS, BLM, and BLM + MLN groups. Scale bar, 50 μm. f–g Quantitative RT-PCR was performed to analyze the mRNA expression of E-cadherin (Cdh1) and Sftpc. n = 5; *P < 0.05, **P < 0.01. h E-cadherin, a marker of alveolar epithelial cells, was identified by immunoblot analysis. n = 6; *P < 0.05, **P < 0.01