| Objective Paraquat(PQ)poisoning is a kind of critically ill,which is common in clinic.And the main target organ of PQ was lung in which acute lung inflammation and pulmonary fibrosis occured.The mortality of PQ poisoning is high,but there is no mature and effective treatment program.In the early stage of the experiment confirmed diammonium glycyrrhizinate(DG)could increase the expression of GR in rats with ALI and also could inhibit the overexpression of TLR4,TNF-ɑ,NF-κB and IL-18 in rats with PQ poisoning,and then improve the prognosis of rats.The intention of the study is to explore the expressions of GR,HMGB1,TLR4,Myd88,NF-к B p65,TNF-α and TGF-β1 what were regulated by DG in paraquat lung injury model of alveolar epithelial cell typeⅡ(AECⅡ).Methods The cells were divided into six groups: The NS group was induced 24 h without any drugs.The PQ group was induced 24 h by1000μmol/L PQ.The DG group was induced 2h by 0.6mg/mL DG,then,was induced 24 h by 0.6mg/mL DG + 1000μmol/L PQ.The PR group wasinduced 2h by 100 n M RU486,then,was induced 24 h by 100 nM RU486+ 1000μmol/L PQ.The PDR group was induced 2h by 100 nM RU486,then,was induced 2h by 100 nM RU486+0.6mg/mL DG,eventually,was induced 24 h by 100 nM RU486+0.6mg/mL DG+1000μmol/L PQ.The NE group was induced 24 h by 0.33μ/mL absolute ethyl alcohol.The effects of PQ and DG on growth of alveolar epithelial cell were measured by MTT assay.The morphology of the cell was observed by inverted microscope.The gene expressions of GR,HMGB1,TLR4,Myd88,NF-кB p65,TNF-α and TGF-β1 were detected by RT-PCR.The ELISA assay was applied to measure the GR,HMGB1,TLR4,MyD88,NF-κB p65,TNF-αand TGF-β1.Results(1)The survival rate of rat alveolar epithelial cell was decreased by PQ,and the IC50 value for 24 h was 920.87μmol/L.The survival rates were(88.12±3.15)%,(81.39±3.31)%,(70.90±3.40)%,(59.80±3.15)%,(48.31±3.58)%,(31.56±3.74)%,(16.46±3.16)%in 200μmol/L,400μmol/L,600μmol/L,800μmol/L,1000μmol/L,1500μmol/L,2000μmol/L PQ treatment groups.(2)And DG increased the survival rate of PQ-induced alveolar epithelial cell.The survival rates were(47.83±0.54)%,(51.99±1.37)%,(59.32±2.34)%,(66.40±3.26)%,(64.89±3.37)%,(60.78±2.24)%,(55.09±2.42)%,(48.72 ± 0.40)% in 0 mg/mL,0.2mg/mL,0.4mg/mL,0.6mg/mL,0.8mg/mL,1mg/mL,1.5 mg/mL,2mg/mL DG treatment groups.(3)In the PQ group,PR group,DG group and PDR group,the cell membrane was shrunk,the cell morphology was irregular,cell adherence was bad,and cell apoptosis,cell debris also could be seen.While the cell injury of DG group and PDR group was significantly less than that of PQ and PRgroup.(4)The levels of GR in PQ and DG group were lower than NS group(respectively,P<0.001).While,the levels of TLR4,MyD88,NF-кB p65,HMGB1,TNF-α,TGF-β1 mRNA in PQ and DG group were higher than those in NS group(respectively,P<0.01).And,the level of GR in DG group was higher than PQ group(P<0.01).But the levels of TLR4,MyD88,NF-кB p65,HMGB1,TNF-α,TGF-β1 in DG and PDR group were lower than those in PQ group(respectively,P<0.01).(5)Compared with DG group,the levels of HMGB1,TLR4,MyD88,NF-кB p65,TNF-α and TGF-β1 in PDR group were not statistically significant(respectively,P>0.05).Compared with PQ group,those in PR group were not statistically significant(respectively,P>0.05).The levels of HMGB1,TLR4,MyD88,NF-кB p65,TNF-α and TGF-β1 in NS group and NE group were not statistically significant(respectively,P>0.05).Conclusions Diammonium Glycyrrhizinate can attenuate the injury in rat alveolar epithelial cells caused by paraquat poisoning.And it can increase the level of GR,decrease the expressions of TLR4,MyD88,NF-κB p65,HMGB1,TGF-β1 and TNF-α.But the anti-inflammatory mechanism of DG is different with hormone,and can’t be effected by glucocorticoid receptor blockers.The study provides a theoretical basis for the prevention and treatment of acute lung injury caused by paraquat poisoning. |
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