Effects Of Diammonium Glycyrrhizinate On The Expression Of TLR-4and NF-κB In Rat’s Lung With Acute Lung Injury Induced By Paraquat

Objective To study the effects of diammonium glycyrrhizinate (DG) onthe expressions of TLR-4, NF-κBIL-6, IL-17in rat’s lungs with acute lunginjury(ALI) induced by paraquat(PQ) poisoning, and to explore it’s protectiveeffects and mechanisms.Methods Fifty healthy SD rats were randomly divided into three groups:group paraquat (PQ group)，glycyrrhizin diammoniumintervention group (DGgroup) and control group (NS group). The paraquats (100mg/kg) wereadministered by gavage in the PQ group and the DG group, the NS group withthe same dose of saline. The glycyrrhizin diammonium (50mg/kg/day) wereadministeredimmediately by intraperitoneal injection in the DG group, while thesame dose of saline were injected in the PQ group and NS group. The rats weresacrificed after48hours, detecting the blood oxygen pressure of abdominalaortic and lung wet to dry weight ratio of the lungs, taking HE staining toevaluat the injury of the lung tissue, TLR-4mRNA and NF-κB mRNA od lungdetected by RT-PCR and immunohistochemistry, and the IL-6, IL-17of lugs andblood measured by the ELISA assay. The mortality rate was observed in Another50healthy SD rats in7days, whose disposals were as the same above.Results The PaO2of PQ group and DG group were significantly lowerthan NS group (p<0.01), and that of DG group was significantly higher than the PQ group (p<0.01). Comparingwith NS group, W/D, the expressions of TLR-4mRNA and NF-κB mRNA in lung tissue and blood IL-6, IL-17in PQ group andDG group were significantly elevated (p<0.01), andthose ofDG group weresignificantly lower than PQ group (p<0.01). HE staining showedthe alveolarstructural of NS group was clear integrity, thin wall without edema, bubblechamberinflammatory exudate, and bleeding in visible light microscopy, whilethose of PQ group, DG group showed pulmonary edema, hemorrhage, exudationand inflammatory cell infiltration, a large number of alveolar atrophy oremphysema-like changes, alveolar septal thickening obvious, and DG lesionswere lighter than the PQ group. The immunohistochemistry of TLR-4, NF-κB inthe NS group was mainly expressed in bronchial epithelial cells and alveolarepithelium, and the expression is very weak, but those of PQ and DG groupwere significantly increased, and they mainly expressed in bronchial epithelialcells and inflammatory cells, positive staining area increased significantly(p<0.05), and which of them of the expression of DG group were weaker thanthose of PQ group (p<0.05). The mortality of PQ group and DG grouprespectively was90%,40%, and the rats of the NS groupwere no death.Conclusions The paraquat can inducelung injury in rat, and our studyindicated he expressions of TLR-4mRNA, NF-κBmRNA, IL-6, IL-17weresignificantly increased. But the Diammonium Glycyrrhizinate alleviated acutelung injury in ratscaused by paraquat poisoning, which may be associated withdecreaseing the expressions of the TLR-4and NF-κB.