Protective Effect Of Small Molecule Drug ITE On LPS-induced Acute Lung Injury In Rats And Its Mechanism

Objective To study the protective effect of small molecule drug ITE on LPS-induced acute lung injury in rats and to explore its mechanism.Methods 48 SPF male SD rats(220-250 g)were randomly divided into 4 groups(n=12): normal saline(Control group),lipopolysaccharide group(LPS group),dexamethasone(DXMS group),small molecule Drug ITE(ITE group).The rat model of ALI was established by instillation of LPS in the exposed airway.LPS(5 mg/Kg)was instilled into the tracheal tube of ALI group,DSMX group and ITE group,and the same amount of normal saline was instilled into the tracheal tube of Control group.Two groups of rats were infused with airway for 2 hours,intraperitoneal injection: DXMS(2mg/kg)and ITE(2mg/kg)were injected intraperitoneally in the DXMS group and ITE group,respectively,while the Control group and the LPS group were injected.The physiological saline was administered again in the intervention group at 24 hours and 48 hours after the first intraperitoneal injection.The rats were sacrificed 72 hours after the first intraperitoneal administration,and lung tissue and alveolar lavage fluid(BALF)were taken for further testing.The living conditions of rats and the general condition of rat lung tissues were observed and recorded.The pathological morphology of rat lung tissues was observed by HE staining.The pathological damage of rat lung tissues was evaluated by Smith scoring standard.The weight of rat lung tissues was weighed and calculated.Pulmonary wet-to-dry weight ratio(W/D);after counting the total number of cells in BALF,the neutrophil count and white blood cell count were counted by high-power microscope after Ray-Jie’s staining;inflammatory factor IL in BALF was detected by ELISA.-6,TNF-α,MCP-1 concentration;Western blot analysis of NF-κB,Ah R and its downstream target gene CYP1A1 protein expression.Results(1)The ALI model was successfully constructed by instilling LPS in the exposed airway.ITE and DXMS significantly ameliorated the pathological changes of lung tissue caused by LPS stimulation.Compared with the LPS group,lung injury was significantly reduced in the ITE group and the DXMS group,the degree of inflammatory cell infiltration was reduced,and the lung tissue structure was normal.(2)Compared with Control,lung injury scores were significantly higher in the LPS group(p < 0.001).Compared with the LPS group,the lung injury scores of the DXMS group and the ITE group were significantly lower(p < 0.05).In addition,there was no significant differencein the lung score of the lung tissue between the DXMS group and the ITE group(p>0.05).(3)Compared with the Control group,the W/D ratio of the LPS group was significantly increased(p < 0.001).Compared with the LPS group,the W/D ratio of the DXMS group and the ITE group was significantly lower(p<0.05).In addition,compared with the DXMS group,the W/D ratio of lung tissue in the ITE group was significantly lower(p<0.05).(4)Compared with the Control group,the total number of cells,the number of neutrophils,and the number of white blood cells in the BALF of the LPS group were significantly increased(p<0.05).Compared with the LPS group,the total number of BALF,the number of neutrophils,and the number of white blood cells in the DXMS group and the ITE group were significantly lower(p<0.05).In addition,compared with the DXMS group,the total number of BALF,the number of neutrophils,and the number of white blood cells in the ITE group were not statistically different(p>0.05).(5)Compared with the Control group,IL-6,TNF-α,and MCP-1 levels were significantly increased in the BALF of the LPS group(p<0.001).Compared with LPS group,IL-6,TNF-α and MCP-1 levels in BALF of DXMS group and ITE group were significantly lower(p<0.05).In addition,compared with the DXMS group,the IL-6 content in the ITE group was significantly reduced(p<0.05),but the TNF-α and MCP-1 levels were not statistically different(p>0.05).(6)Compared with the Control group,the expression level of NF-κB protein in the LPS group was significantly increased(p<0.05).Compared with the LPS group,the expression of NF-κB protein in the DXMS group and the ITE group was significantly decreased(p<0.01).In addition,the NF-κB protein was significantly reduced in the ITE group compared with the DXMS group(p<0.05).(7)Compared with the Control group,the expression levels of Ah R and CYP1A1 in the LPS group were significantly decreased(p<0.05).Compared with LPS group,the expression of Ah R and CYP1A1 protein in DXMS group and ITE group increased significantly(p<0.01).In addition,compared with the Control group,CYP1A1 protein expression in the DXMS group was not statistically significant(p>0.05).Conclusion(1)The ALI rat model can be successfully induced by the exposed intratracheal instillation of LPS.Based on this,the therapeutic effect of Pharmacy on ALI and its mechanism of action are further studied.(2)ITE can up-regulate the expression of Ah R in lung tissue,thereby inhibiting the expression of NF-κB signaling pathway and downstream inflammatory factors,thereby exerting an inflammatory response to control ALI.(3)Ah R may be a possible target for intervention in ALI.Small molecule drugs are expected to be effective measures for ALI treatment,laying a theoretical foundation forearly effective prevention and treatment of acute lung injury.