Protective Effects Of Shiqiwaigancha (SQ) On Lipopolysaccharide-induced Acute Lung Injury Of Rats

Objective: To evaluate the protective effects of ShiQiWaiGanCha(SQ) on lipopolysaccharide(LPS)-induced acute lung injury(ALI) in rats and its underlying mechanisms of action, which provided theoretical and experimental basis for further improving its value of clinical application.Methods: Ninty male Sprague-Dawley rats were randomly divided into 5groups, including control, model(LPS, 5 mg/kg), dexamethasone(DEX, LPS+DEX 5 mg/kg), SQ-H(LPS+SQ-H 20 g/kg) and SQ-L(LPS+SQ-L 10 g/kg) groups, with 18 rats in each group. Rats were challenged with intravenous injection of LPS(5 mg/kg) to mimic acute lung injury(ALI) model. Rats were given with SQ(20 g/kg, 10 g/kg) by oral administration once a day for 3 consecutive days before LPS challenge. DEX was intraperitoneally administrated to rats one hour prior to the injection of LPS. At 6 h after LPS challenge, lung tissues and bronchoalveolar lavage fluid(BALF) were collected. Protein content and the number of inflammatory cells in BALF were determined. The lungs were collected for measurement of wet weight to dry(W/D) ratio and thelung permeability. Lacate dehydrogenlase(LDH), myeloperoxidase(MPO) activity and malonaldehyde(MDA) content of lung were measured according to manufacturer's instructions of assay. Tumor necrosis factor-alpha(TNF-?) and Interleukin-1?(IL-1?) levels of lung were measured using enzyme-linked immunosorbent assay(ELISA). The nuclear factor kappaB(NF-?B) signaling pathway activation was determined by western blot analysis. Histopathologic examination also measured in lung of ALI rats.Results: SQ significantly reduced the lung weight of wet to dry(W/D) ratio(P < 0.05 vs model) and the lung permeability(P <0.05 vs model), decreased protein content(P < 0.05 vs model) and the number of neutrophils(P <0.05 vs model) and macrophages(P <0.05 vs model) in BALF of lung. Meanwhile, SQ obviously inhibited the activity of LDH(P <0.05 vs model) and MPO(P <0.05 vs model), and decreased MDA content(P < 0.05 vs model) in lung tissues of ALI rats. Moreover, SQ decreased TNF-?(P < 0.01 vs model) and IL-1?(P < 0.05 vs model)levels in lung tissues and alleviated LPS-induced lung histopathological damage. Furthermore, SQ efficiently weakened lung NF-?B p65 protein expression(P < 0.01 vs model) of ALI rats.Conclusion: SQ possessed protective effects on LPS-induced ALI through reducing leakage of inflammatory cells, decreasing anti-peroxidation damage of organism and inhibiting NF-?B signalingpathway.