OBJECTIVETo investigate the intervention and mechanism of ambroxol combined with low-dose heparin on oxidative stress, TNF-alpha and IL-1beta in rabbits with acute lung injury (ALI).

METHODSTwenty-four healthy Japanese rabbits were randomly divided into three groups: (1) Normal saline control group (NC), (2) Oleic acid injury group (OA), (3) Ambroxol + low-dose heparin therapy group (AH). After the success of ALI model, AH group was injected ambroxol + low-dose heparin, while the NC group and OA group were injected the same dose of normal saline by the same method. Arterial oxygen tension (PaO2), tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) at different time points were determined. The pathological manifestation of both side lungs was observed at the end of expeiment. The activity of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), xanthine oxidase (XO) and the content of malondialdehyde (MDA) in bronchoalveolar lavage fluid (BALF) and lung tissue homogenate were tested. The apoptosis index was detected. The lung wet/dry (W/D) ratio was calculated. The pathological changes in lung tissue were observed by light microscopy, and the ultrastructural changes of lung tissue were observed by electron microscopy.

RESULTS(1) The instructive injury induced by ALI observed under electron microscope and light microscope and W/D was decreased significantly in AH group. (2) PaO2 was improved significantly in AH group, compared with that in OA group (P < 0.01). (3) The activity of GSH-Px and SOD in AH group increased significantly (P < 0.01 or P < 0.05) but the activity of XO and the content of MDA decreased significantly (P < 0.01), compared with those in OA group. (4) Except the content of IL-1beta in serum before treatment, the content of IL-1beta and TNF-alpha in serum, BALF, lung tissue homogenate of OA group increased significantly (P < 0.01), and those were obviously improved in AH group. (5) Apoptosis index (AI) in AH group decreased significantly (P < 0.01) compared with that in OA group.

CONCLUSIONIn ALI induced by OA, IL-1beta and TNF-alpha increases significantly and involved in the occurrence and development of ALI. Ambroxol combined with low-dose heparin can reduce lung cells oxidative stress to inhibit the release of IL-1beta and TNF-alpha, which play a role in the treatment of ALI.