Effect of toluene diisocyanate on reactive oxygen species production and permeability of human bronchial epithelial cells in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of toluene diisocyanate (TDI) on the production of reactive oxygen species (ROS) and the permeability of human bronchial epithelial (HBE) cells.</p><p><b>METHODS</b>TDI-human serum albumin (TDI-HSA) conjugate was prepared using a modified Son's method. MTT assay was used to assess HBE cell viability after exposure to different concentrations of TDI-HSA. The level of intracellular ROS of HBE cells was detected by flow cytometry with an oxidation-sensitive fluorescent probe 2',7'-dichlorofluorescein diacetate (DCFH-DA) uploading, and the permeability of cell monolayer was assessed by detecting the transepithelial electrical resistance (TEER).</p><p><b>RESULTS</b>The exposure to 120 µg/ml TDI-HSA did not obviously affect the cell viability. Compared with the control group, the intracellular fluorescent intensity increased significantly in the cells exposed to 20, 60, and 100 µg/ml TDI-HSA (P<0.05). The intracellular ROS production increased significantly after 100 µg/ml TDI-HSA treatment (P<0.05), but the increment in ROS production was significantly suppressed by pretreatment of the cells with N-acetylcysteine (NAC) (P<0.05), which also enhanced the TEER decreased by TDI-HSA treatment (P<0.05).</p><p><b>CONCLUSIONS</b>TDI enhances the permeability of HBE cell monolayer partially through a ROS-mediated pathway, suggesting the importance of oxidative stress in TDI-induced pulmonary diseases.</p>

Expression of high mobility group box-1 in the lung tissue and BALF of asthmatic mice and the influence of dexamethasone / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the expression of high mobility group box-1 (HMGB1) in the lung tissue and bronchoalveolar lavage fluid (BALF) of asthmatic mouse models and the influence of dexamethasone (DM).</p><p><b>METHODS</b>Eighteen female Balb/C mice were randomly divided PBS control group, OVA group and OVA/DM group, and asthmatic mouse models were established in the latter two groups. The airway responsiveness of the mice was assessed by whole-body plethysmography, and the cells in the BALF were counted and classified, with the supernatants of the BALF collected for detection of the level of HMGB1 by ELISA. The left lung of the mice was collected for HE staining, and the expression of HMGB1 in the right lung tissue was detected by Western blotting.</p><p><b>RESULTS</b>Asthmatic mouse models were successfully established. The level of HMGB1 in the BALF was significantly higher in OVA group than in the control group (6.31 ± 4.05 ng/ml vs 2.59 ± 0.73 ng/ml, P = 0.017), but no significant difference was found between OVA/DM group (3.39 ± 0.50 ng/ml) and OVA group (PP = 0.052). The expression of HMGB1 relative to tubulin was significantly higher in OVA group than in the control group (2.08 ± 0.87 vs 0.85 ± 0.30, P = 0.032), but similar between OVA/DM group (1.15 ± 0.48) and OVA group (PP = 0.133).</p><p><b>CONCLUSION</b>The expression of HMGB1 is obviously increased in the lung and BALF of asthmatic mice and DM produces no significant effect on HMGB1 expression, suggesting that HMGB1 may serve as a new therapeutic target for asthma treatment.</p>