Expression of NF-κB and its effect on IL-4 in cultured cells from bleomycin-injured lung tissue in mice

[Objective] To investigate the expression of NF -κB and its effect on IL-4 expression in cultured cells from bleomycin(BLM)-injured lung tissue in mice. [Methods] Fifteen C57BL/6 mice (female, 8 wk of age, 17 to 20 g body weight) were randomly divided into 3 groups. The experimental group and the control group were injected normal saline via the tail vein, respectively, but the treatment group was injected antisense oligonucleotids to P65 subunit of NF-κB (900 μg/animal dissolved in 200 μL saline). 6 hours after intravenous injection, the experimental group and the treatment group were treated with BLM-A5 (5 mg/kg dissolved in 20 μL saline) by intratracheal installation, respectively, but the control group was treated with normal saline (20 μL). On day 3 after intratracheal administration, the mice of every group were sacrificed and the cells from lung tissues were cultured. The immunohistochemistry and microscope image analysis were completed to detect the expression of P65 and IL-4 with the average integrated optical density (aiOD). At the same time, the negative controls were set up, respectively. [Results] The aiOD of P65 in the control group, the experimental group and the treatment group were (1.03±0.37), (462.04±152.25) and (29.38±3.62), respectively, the negative control was (0.82±0.41). The expression of P65 in the experimental group increased markedly in comparison with the control group (P 0.05) and the treatment group (P 0.05). However , the treatment group was still significantly higher than the control group (P 0.01), but there was no difference between control group and negative control (P 0.05). The aiOD of IL-4 in the control group, the experimental group and the treatment group were (29.36±2.00), (248.19±39.16) and (47.66±5.61), respectively, the negative control was (0.97±0.37). The expression of IL-4 in the experimental group was also significantly higher than in control group (P 0.01) and treatment group (P 0.01). The expression of IL-4 in the control group was markedly higher than negative control (P 0.01), but significantly lower than that in treatment group (P 0.05). The expression of P65 was positively correlated with IL-4 expression on cultured cells from lung tissue in treatment group (r=0.907; P 0.05). [Conclusions] The expression of NF-κB is significantly increased and augments the expression of IL-4 indirectly on lung interstitial cells during the process of bleomycin-induced lung injury in mice. The increased NF-κB expression in interstitial lung cells might be very important in the pathogenesis of bleomycin-induced lung injury.