Knockdown of LincRNACOX2 Alleviates Oxidative Stress in Pathophysiology of Acute Lung Injury

Abstract

Acute lung injury (ALI) has a complicated etiology that involves oxidative stress and inflammation. The role of lncRNACox2 (lincCOX2) in ALI regulation remains unclear. In this study, the ALI model of mice and MLE-12 cell was induced by LPS. To investigate the expression of lncRNACox2 in these ALI models, we employed a nanomagnetic bead-based RNA extraction method for quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis. This enabled us to determine the levels of lncRNACox2 expression and evaluate knockdown efficiency. Moreover, we also examined lung tissue histopathology using H&E staining. Cell survival and apoptosis rates were evaluated through CCK-8 and flow cytometry, respectively. The concentration of inflammatory factors was measured using ELISA. Additionally, the concentration (8-OHdG and MDA) and enzymatic activity (CAT, GSH-Px, and SOD) of oxidative stress related factors were measured by biochemical method. The western blot was performed to present the key proteins expression level in Nrf2/ARE signaling pathway in cytoplasm and nucleoprotein. The ALI mouse model was successfully established. The histopathology change and inflammatory cells were observed by H&E staining in LPS treated groups. The expression of lincCOX2 was up-regulated in ALI tissue. LPS induced more cell death in ALI, and the knockdown of lincCOX2 improved the cell survival and suppressed the apoptosis in ALI cell. Furthermore, In addition, downregulation of lincCOX2 attenuated inflammation and oxidative stress in lung cells in ALI. The concentration of 8-OHdG and MDA were highest in the LPS group while reduced by the sh-lincCOX2, the activity of CAT, GSH-Px, and SOD was reduced in the LPS induced ALI and increased by the sh-lincCOX2. In ALI, the distribution of Nrf2 protein is transferred from cytoplasm to nucleus. Furthermore, the lincCOX2 regulated oxidative stress via Nrf2/ARE signaling pathway in ALI. Overall, downregulation of lincRNACOX2 alleviates oxidative stress in ALI via Nrf2/ARE Pathway. This study suggests that lincCOX2 may be a potential target for the treatment of ALI.