The Expression Change And Related Mechanism Of P120and NF-κB In The Repair Of Airway Epithelial Cells After Injured By LPS In C57Mice

I. ObjectiveIn this study, we established mice acute lung injury model by lipopolysaccharide intratracheal injection in C57mice, detected the changes of p120expression and intracellular localization, the changes of NF-κB signaling pathways related protein expression and cytokine IL-8expression in airway injury and repair. Then preliminary discussed the airway inflammation mechanisms in C57mice.II. MethodsHealthy C57male mice were randomly dividing into experimental group Id,4d,7d,14d group and the control group (n=8). Experimental group mice received LPS (5mg/kg) by intratracheal injection. The control group mice received normal saline by intratracheal injection. HE staining was used to observe the airway epithelial morphological changes of C57mice. Immunohistochemistry detected the intracellular localization and expression of p120in airway epithelial cells. We detected the expression of protein p120, NF-κB, IκBα, p-IκBα in lung tissues via western blot. Then ELISA method was used to detect the expression level of cytokines IL-8.III. Results1. The morphological changes in airway epithelial of C57mice treated with LPSThe1day group did not appear significant acute inflammatory changes in airway epithelial continuity and the alveoli. The4day group showed significant pathologic changes, such as alveolar wall thickening, inflammatory cell infiltration, and even bronchiolar epithelium necrosis. The7day group still showed significant pathologic changes, such as alveolar wall thickening, inflammatory cell infiltration, but recovered part of the damage region. The14day group showed the morphologic change of post-injury repair, such as epithelial cells arranged in dense, level increased, was the proliferation of change. Control group mice bronchial epithelial cells arranged in neat rows, no obvious damage and repair changes.2. The expression and cellular localization of p120In control group p120presented continuous brown yellow linear expression around the airway epithelial cells. In LPS group p120cell membrane expression was first reduced then recover(compared with control group, p<0.05). The1day group, p120still showed continuous brown yellow linear expression around the airway epithelium. The4day group and the7day group, the expression of p120in murine airway epithelial cell membrane was reduced, and p120in the cytoplasm was visible. The14day group, part of the region p120recovery in murine airway epithelial cell membrane brown yellow continuous linear expression.3. Expression of related protein were changed in lung tissue treated with LPS1). Western bolt showed the p120was rich in lung tissue of control group. In LPS group, the expression of p120showed a trend of recovery in the first reduced (each LPS group compared with control group, p<0.05). The expression of p120was decreased significantly in the1day group and the4day group, then p120in the7day group and the14day group has been restored, but still lower than control group.2). Compared with the level of NF-κB expression of control group, LPS1day group and the4day group was significantly reduced, then the7day group and the14day group was recovery slowly (compared with control group, the1day group, the4day group and the7day group, p<0.05). The14day group and the control group showed no significant difference.3). Compared with control group, p-IκBα in the lung tissue of mice presented a first increase then decrease trend. The expression of IκBα first reduced then recovered (compared with control group, LPS lday group, the4day group and the7day group, p<0.05).The14day group and the control group showed no significant difference.4. The results of ELISA showed that the level of IL-8expression was first increased then decreased after treated with LPS (each LPS group compared with control group, p<0.05)Ⅳ.ConclusionThese data displayed that in C57mice ALI induced by LPS, may down-regulating airway epithelial cells p120expression and cause the changes in the intracellular localization. And the decreasing of p120caused IκBα phosphorylation and degradation, thereby activated the NF-κB signaling pathway, promoting cytokines IL-8generation and secretion. Then by this way involved in airway inflammation and hyperplasia of the repair process.