muramidase and Hyperoxia

Under mechanical ventilation with high-inspired oxygen concentration, diffuse alveolar damage was found to take place in some patients. To clarify the molecular pathophysiology of this condition, we investigated the time course of gene expression changes induced by hyperoxia exposure in mouse lung using real-time quantitative polymerase chain reaction (qPCR). Our results normalized by glyceraldehyde 3-phosphate dehydrogenase showed that mRNA levels of cysteine rich protein 61 (CYR61) and connective tissue growth factor (CTGF) were significantly upregulated, while those of surfactant-associated protein C (SFTPC), cytochrome P450, 2F2 (CYP2F2), Claudin 1, (CLDN1), membrane-associated zonula occludens protein-1 (ZO-1), lysozyme (LYZS), and P lysozyme structural (LZP-S) were significantly downregulated. Increasing level of mRNAs, each encoding CYR61 and CTGF, suggests a serious risk of fibrosing alveolitis. Decrease in levels of mRNAs for SFTPC, CYP2F2, CLDN1, ZO-1, LYZS, and LZP-S suggests alveolar dysfunction and disruption of the immune system. Moreover, we confirmed apoptotic conditions, such as significant upregulations of mRNA levels in Myc and Galectin-3. Hyperoxic condition probably yielded reactive oxygen species (ROS), which resulted in a malignant cycle of ROS production by Myc overexpression.

Topics: Animals; Claudin-1; Connective Tissue Growth Factor; Cysteine-Rich Protein 61; Cytochrome P-450 Enzyme System; Down-Regulation; Galectin 3; Gene Expression Profiling; Hyperoxia; Immunohistochemistry; Intercellular Signaling Peptides and Proteins; Male; Membrane Proteins; Mice; Mice, Inbred C57BL; Muramidase; Oligonucleotide Array Sequence Analysis; Peptides; Phosphoproteins; Phosphoric Monoester Hydrolases; Polymerase Chain Reaction; Proto-Oncogene Proteins c-myc; Pulmonary Alveoli; Pulmonary Surfactant-Associated Protein C; RNA, Messenger; Up-Regulation; Zonula Occludens-1 Protein