Antidepressive Agents, Second-Generation/toxicity; Fluoxetine/toxicity; Hyperoxia/complications; Lung Injury/etiology; Selective Serotonin Reuptake Inhibitors/toxicity; Animals; Animals, Newborn; Base Sequence; Bronchopulmonary Dysplasia/etiology; Bronchopulmonary Dysplasia/genetics; Bronchopulmonary Dysplasia/metabolism; Bronchopulmonary Dysplasia/pathology; Disease Models, Animal; Female; Humans; Hyperoxia/genetics; Hyperoxia/metabolism; Infant, Newborn; Lung Injury/genetics; Lung Injury/metabolism; Lung Injury/pathology; Matrix Metalloproteinase 12/genetics; Matrix Metalloproteinase 12/metabolism; Matrix Metalloproteinase 2/genetics; Matrix Metalloproteinase 2/metabolism; Muscle, Smooth, Vascular/drug effects; Muscle, Smooth, Vascular/pathology; Neuroendocrine Cells/drug effects; Neuroendocrine Cells/metabolism; Neuroendocrine Cells/pathology; Pregnancy; RNA, Messenger/genetics; RNA, Messenger/metabolism; Rats; Rats, Sprague-Dawley; Respiratory Muscles/drug effects; Respiratory Muscles/pathology; Ubiquitin Thiolesterase/metabolism; Up-Regulation/drug effects; Vascular Endothelial Growth Factor A/genetics; Vascular Endothelial Growth Factor A/metabolism