CCL2 and bronchopulmonary dysplasia: Administration of hydrogen reduced the LPS-induced BPD by significantly lessening placental inflammatory factors (IL-6, IL-18, IL-1β, CCL2, CXCL1, NLRP3 and Casp1) to fetal circulation, then further proceeded to alleviate the FIRS and reduced the infiltration of proinflammatory cells in fetal lung tissue, resulting in the increased amount of alveoli and the decreased area of pulmonary septum to ultimately normalize the disorder of neonatal BPD induced by LPS.