ADAM Proteins/pharmacology; Gene Expression Regulation, Developmental/physiology; Myelin Sheath/drug effects; Schwann Cells/drug effects; ADAM Proteins/deficiency; ADAM Proteins/genetics; ADAM17 Protein; Age Factors; Amyloid Precursor Protein Secretases/metabolism; Animals; Animals, Newborn; Antioxidants/pharmacology; Ascorbic Acid/pharmacology; Aspartic Acid Endopeptidases/metabolism; Axons/metabolism; Axons/pathology; Axons/ultrastructure; Cells, Cultured; Coculture Techniques/methods; Disease Models, Animal; Embryo, Mammalian; Femoral Nerve/metabolism; Femoral Nerve/pathology; Femoral Nerve/ultrastructure; Ganglia, Spinal/cytology; Gene Expression Regulation, Developmental/drug effects; Gene Expression Regulation, Developmental/genetics; Homeodomain Proteins/genetics; Homeodomain Proteins/metabolism; Humans; Mice; Mice, Knockout; Microscopy, Electron, Transmission; Motor Neurons/drug effects; Motor Neurons/physiology; Myelin Basic Protein/metabolism; Myelin Sheath/metabolism; Myelin Sheath/ultrastructure; Neuregulin-1/metabolism; Neurofilament Proteins/metabolism; Polyradiculoneuropathy/genetics; Polyradiculoneuropathy/metabolism; Polyradiculoneuropathy/pathology; RNA, Small Interfering/pharmacology; Rats; Schwann Cells/physiology; Schwann Cells/ultrastructure; Signal Transduction/genetics; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods; Transcription Factors/genetics; Transcription Factors/metabolism; Transfection/methods