Effects of hydrogen sulfide on the expressions of nuclear factor-κB and intercellular adhesion molecule 1 in pulmonary tissue of rats with acute lung injury

Abstract

To explore the potential effects of hydrogen sulfide (H(2)S) on nuclear factor kappa B (NF-κB) and intercellular adhesion molecule 1 (ICAM-1) in lung tissue with oleic acid (OA)-induced acute lung injury (ALI) in rats. Forty-two rats were randomly divided into 3 groups: control (n = 6), OA (n = 18) and OA + NaHS (n = 18). Rats in the OA group received an intra-tail vein injection of oleic acid 0.1 ml/kg while those in the OA + NaHS group an intraperitoneal injection of NaHS 56 µmol/kg at 30 mins before OA injection. The OA and OA + NaHS groups were subdivided into 3 subgroups depending on the therapeutic duration: 2 h (n = 6), 4 h (n = 6) and 6 h (n = 6). Rats in the control group received an intra-tail vein injection of normal saline 0.1 ml/kg. Bronchioalveolar lavage fluid (BALF) was collected and the leucocytic differential count of sediment examined. The extent of lung injury was evaluated by the index of quantitative assessment (IQA). The H(2)S level in lung tissue was measured by sensitive sulphur electrode. The nuclear translocation of NF-κB and the expression of ICAM-1 in alveolar epithelial cells were measured by immunohistochemical staining. Compared with the control group, the BALF percentage of polymorphonuclear (PMN) cell was significantly higher at 2, 4 and 6 h in the OA-treated rats [(74.5 ± 3.0)%, (80.2 ± 2.0)%, (87.2 ± 2.7)% vs (3.1 ± 1.6)%, all P < 0.01]. And the value of IQA increased significantly versus those at 2, 4 and 6 h in the control group (5.2 ± 0.8, 6.4 ± 0.6, 6.8 ± 0.8 vs 0.4 ± 0.6, all P < 0.01). And the levels of H(2)S in lung tissue decreased at 2, 4 and 6 h [(21.20 ± 0.38) µmol/g, (20.80 ± 0.53) µmol/g, (18.92 ± 0.75) µmol/g vs (26.81 ± 0.65) µmol/g, all P < 0.01]. Moreover, the nuclear expression of NF-κB and the membranous expression of ICAM-1 in the alveolar epithelial cells in OA group rats was significantly higher than those of the control group (all P < 0.05). After the dosing of H(2)S donor (NaHS), the BALF percentage of PMN cell and the lung IQA decreased in the three subgroup rats (2, 4 and 6 h) versus the OA group. And the concentration of H(2)S increased significantly in the 4 h and 6 h subgroups versus the OA group at the corresponding time points. Simultaneously, the nuclear expression of NF-κB and the membranous expression of ICAM-1 in alveolar epithelial cells were significantly lower than that of the OA group at 4 h and 6 h subgroups (all P < 0.05). H(2)S may play a protective role in the ALI rats through the suppression of lung inflammation. And the inhibited expression of alveolar epithelial cell NF-κB mediates the anti-inflammatory effects of H(2)S.