Effects of ambroxol combined with dexamethasone on pulmonary surfactant protein A in acute lung injury rats induced by lipopolysaccharide

AIM To observe the effects of ambroxol(Amb) /dexamethasone(DXM) co-administration on the changes of pulmonary surfactant protein A(SP-A) in lipopolysaccharide(LPS)-induced acute lung injury( ALI) rats. METHODS Forty-two SD rats were divided randomly into 6 groups with 7 each: blank control group(group C), negative control group(group N), model group(group M), Amb intervention group(group A), DXM intervention group(group D), Amb and DXM combined intervention group(group AD). The group N was given normal saline 2 mL via tail vein, while no treatment in the group C. All the other four groups were given LPS 5 mg·kg-1and group A was given Amb 100 mg·kg-1, group D was given DXM mg·kg-1,group AD was given Amb 60 mg·kg-1+ DXM 4 mg·kg-1. The indexes of blood gas analysis, wet to dry(W/D)of lung and lung tissue pathology were examined. The expression of SP-A and the level of SP-A mRNA was measured with immunohistochemistry and reverse transcription-polymerasechain reaction(RT-PCR). RESULTS There was no significant difference in each index between group C and group N( P 0.05). Compared with those in the group C, the levels of arterial blood pH and PaO2 decreased, W/D of lung increased, and the expression of SP-A content and mRNA decreased in the group M(P 0.05), and with obvious pathological injury. Compared with those in the group M, pH and PaO2 increased, W/D of lung decreased, the expression of SP-A content and mRNA increased in each drug group(P 0.05), and the pathological damage was improved.The improvement was better in the group AD than group A and group D(P 0.05). CONCLUSION Both Amb and DXM can improve the level of SP-A in ALI rats induced by LPS, and combination of them are better.