Objective: To observe the effects of adenovirus borne IΚB gene, an inhibitor of nuclear factor-ΚB (NF-ΚB), infused via central vein, to treat infectious acute lung injury (ALI) in rats.
Methods: According to random number table method, 30 pathogen-free Sprague-Dawley (SD) rats were randomly divided into three groups: sham group, ALI model group, IΚB gene treatment group, with 10 rats in each group. The rats of IΚB gene treatment group were infused 1 ml adenovirus borne IΚB gene (titre: 1×10(9)pfu ), the rats of sham group and ALI model group were infused 1 ml normal saline through central vein. Subsequently, the rats of ALI model group and the IΚB gene treatment group were given 1 ml lipopolysaccharide (LPS, 5 ml/kg) through tail vein to reproduce model of ALI. On the other hand, the rats of sham group were given 1 ml normal saline through tail vein. Blood gas analysis, the ratio of wet to dry weight (W/D) of lung, plasma contents of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), and protein expression of NF-ΚBp65 in lung tissue were determined, the pathobiological changes in lung tissue were microscopically observed and the scores of lung injury were calculated after 7 days.
Results: The rats in three groups survived, except 1 rat died in ALI model group.Blood pH and partial pressure of arterial carbon dioxide (PaCO(2)) showed no obviously differences among three groups. Partial pressure of arterial oxygen (PaO(2) ) was highest in sham group and the lowest in ALI model group. The plasma content of TNF-α (μg/L) and IL-6 (ng/L ) in ALI model group were obviously higher than those in sham group (TNF-α: 5.20±1.09 vs. 3.01±0.46; IL-6: 540.28±100.78 vs. 214.45±61.37, both P<0.05). The plasma content of TNF-α and IL-6 in IΚB gene treatment group were obviously lower than those in ALI model group (TNF-α: 3.70±0.96 vs. 5.20±1.09, IL-6: 356.49±60.58 vs. 540.28±100.78, both P<0.05), and TNF-α content had restored to the level observed in sham group. The ratio of W/D of lung was lowest in sham group (4.49±0.36) and highest in ALI model group (5.78±0.43), and that of IΚB gene treatment group (5.33±0.38) was lower than that of ALI group. The score of lung injury was lowest in sham group (0.17±0.41) and highest in ALI model group (2.29±0.76), and that of IΚB gene treatment group (1.57±0.53) was lower than that of ALI group. The scale of NF-ΚBp65 immunohistochemistry was lowest in sham group (1.00±0.89) and highest in ALI model group (9.43±1.13), and that of IΚB gene treatment group (4.00±1.15) was lower than the latter. The differences of all the above parameters in three groups were statistically significant (all P<0.05 ).
Conclusion: Increased expression of IΚB gene by an infusion of adenovirus borne IΚB gene through central vein can lower the levels of pro-inflammatory factors, such as TNF-α and IL-6, restrain the NF-ΚB activation, reduce lung water, alleviate alveolar collapse and lung consolidation in ALI in rats, thus lung injury is ameliorated.