Objectives:To evaluate lung injury mechanism in SD rat with nitrogen dioxide(NO2) exposure. 　Methods:In the test-control study, pulmonary malondialdehyde(MDA),glutathione(GSH) and total-antioxidant content(T-AOC) were determined in 10 SD rats with long-term NO2 exposure,10 SD rats with short-term NO2 exposure and 10 SD rats with fresh air as control. 　Results: Pulmonary MDA content was increased and T-AOC was decreased significantly in SD rat exposed to NO2. Pulmonary GSH was decreased significantly in long-term NO2 exposure group as compared with short-term NO2 exposure group and control group. 　Conclusions: Imbalance between oxidant and antioxidant was an important mechanism in the pathogenesis of oxidizing lung injury in SD rat with NO2 exposure.

Objective To explore the expression of heat shock protein (HSP) 90α in outside of different metastatic hepatocellular carcinoma (HCC) cell lines and its role in the cells migration and invasion.Methods The expression of HSP90α was detected by Western blot analysis in conditioned media of MHCC97L and MHCC97H with low and high metastatic HCC cell lines.A small molecule cell-impermeant HSP90 inhibitor DMAG-N-oxide was used to inhibit extracellular HSP90α.Changes of the cells migratory and invasive capability were assessed by in vitro motility and invasion assay.The endogenous matrix metalloproteinase 2 (MMP-2) was demonstrated by Zymography.The expression of extracellular co-chaperone HSP70 and MMP-2 were tested by Western blots and the association between HSP90α,HSP70 and MMP-2 was analyzed by immunoprecipitation.The effects of HSP70 knockdown by siRNA,with or without MMP-2 inhibitor Batimastat,on the level of active MMP-2 and cell migration and invasion were also evaluated.Results HSP90α can express both inside and outside of different metastatic HCC cell lines,and the level of expression was consistent with metastasis potentials.After MHCC97-H cells were treated with a special HSP90α inhibitor DMAG-N-oxide for 24 h,the average migratory cell numbers (28.11 ±3.56) had a significantly reduction,compared with those without treatment group (80.12±4.16) and empty control group (82.24±4.12),respectively (P ＜ 0.01).In vitro invasion assay showed the average invaded cell numbers in treatment group (36.54±4.12) were more fewer than without treatment group (95.12±3.48) and empty control group (101.1 1±3.36),respectively (P =0.017),and accompanying with decreasing of the extracellular MMP-2 activity.HSP70 and MMP-2 could express outside of MHCC97-H cells and interact with HSP90α.Small molecular interfere RNA (siRNA) dramatically inhibited HSP70 expression and reduced the interaction HSP90α with MMP-2 and MMP-2 activity outside MHCC97-H cells,and also suppressed MHCC97-H cells migration and invasion.In addition,combining MMP-2 inhibitor had additive inhibition effects.Conclusion Extracellular HSP90α and HSP70 form chaperone complex to assist in MMP-2 activation and increases HCC cells migration and invasion,which maybe a novel therapeutic target against metastatic HCC.