| ObjectiveAcute lung injury（ALI）is a critical respiratory disorde in clinical practice,which is more common in ICU patients and mainly manifests as acute,diffuse,and inflammatory lung injury.In the past 50 years,there have been in-depth studies on the epidemiology,pathogenesis and pathophysiology of ALI.In addition,randomized trials optimizing mechanical ventilation and fluid therapy in ALI have improved clinical outcomes.Although great progress has been made in improving the supportive treatment of ALI,the mortality rate of ALI is still high,treatment is difficult,and the prognosis is poor.Due to the complex pathogenesis of this disease,which has not yet been fully elucidated,and no effective medical treatment for ALI has been identified,it is very important to study and develop effective drugs for the treatment of ALI.The essence of ALI is an inflammatory response,and existing studies have shown that the ethanolic extract of Euphorbia thymifolia L.has good activity.Therefore,in this experiment,we explored the intervention effect of the ethanolic extract of Euphorbia thymifolia L.on acute lung injury and its mechanism of action,providing a new direction for the development of effective traditional Chinese medicines for the treatment of ALI and a possible prevention and treatment method for acute lung injury,moreover,providing a novel strategy for controlling the initiation and progression of ALI.Method1.Preparation of ethanolic extract of Euphorbia thymifolia L.:Prepare dried Melaleuca chinensis,use 70%ethanol as extraction solvent,and obtain the extract through water bath heating,filtration,filtrate decompression,boiling,centrifugation,and concentration procedures.2.Preparation and grouping of experimental animals:36 8-week-old male Sprague Dawley rats weighing 180-220 g.They were divided into ethanolic extract of Euphorbia thymifolia L.group（group E）,model group（group L）,and blank control group（group N）,with 12 rats in each group.3.Pretreatment of experimental animals:Group E received 20g/kg·d-1of ethanolic extract of Euphorbia thymifolia L.by gavage for 7consecutive days.Group N and group L was given an equal volume of normal saline.4.Model establishment:On the 8th day（d8）from the day of administration,group E were intraperitoneally injected with LPS（lipopolysaccharide）5mg/kg to model,and group N were intraperitoneally injected with an equal volume of normal saline.5.Samples collected:Six hours after modeling,all rats were anesthetized to collect serum samples,and then all rats were sacrificed to collect bronchoalveolar lavage fluid（BALF）and lung tissue samples.6.Pathological sections of rat lung tissues.7.Scoring criteria and scores of rat lung histopathology.8.W/D ratio detection in rat lung tissue.9.To detect the expression of inflammatory factor interleukin-6（IL-6）in rat serum.10.To detect the total protein concentration of BALF from rats.11.Total cell counts in BALF of rats were measured.12.To detect the protein expression of TLR4 in rat lung tissue.13.The activity level of myeloperoxidase（MPO）in the lung tissue of rats in each group was analyzed.Results1.Pathological sections of lung tissues of rats in each group:The ethanolic extract of Euphorbia thymifolia L.alleviated the degree of pathological injury of lung tissues.Compared with group N,the structure of lung tissue in group L was significantly severely damaged,a large number of red blood cells exuded into the alveolar space,and edema and a large number of inflammatory cell infiltration occurred in the alveolar septa;compared with group L,the alveolar structure of lung tissue in group E was not significantly damaged,the integrity of alveolar structure was good,and the indicators such as edema,inflammatory cell infiltration and bleeding degree in the alveolar septa were significantly less than those in group L.2.Pathological score of acute lung injury:The ethanolic extract of Euphorbia thymifolia L.reduced the pathological score of acute lung injury.Compared with group N（0.018±0.009）,the pathological score increased in group L（0.048±0.013）（P<0.01）.The pathological score was decreased in group E（0.031±0.009）compared with group L（P<0.01）.3.W/D ratio:The ethanolic extract of Euphorbia thymifolia L.reduced the W/D ratio and reduced the degree of pulmonary edema.The W/D value of group L（6.48±0.34）was significantly higher than that of group N（5.13±0.57）（P<0.001）,and the degree of pulmonary edema was more severe;the W/D value of group E（5.76±0.45）was significantly lower than that of group L（P<0.01）,and the degree of pulmonary edema was significantly alleviated.4.IL-6 level:The ethanolic extract of P.millefolia decreased the expression of IL-6 in the serum of ratsCompared with group N（27.22±1.21）,the IL-6 levels in the serum of groups L（35.20±1.35）and E were increased（P<0.001）.The IL-6level in the serum of group E（30.48±1.43）was decreased compared with group L（P<0.01）.5.The ethanolic extract of Euphorbia thymifolia L.decreased BALF total protein concentration in rats.Total BALF protein concentration was increased in group L（1.293±0.127）compared with group N（0.496±0.074）（P<0.001）.BALF total protein concentration was decreased in group E（0.808±0.103）compared with L（P<0.001）.6.The ethanolic extract of Euphorbia thymifolia L.decreased BALF total cell counts in rats.The BALF total protein concentration model was higher in group L（199.17±19.84）than in group N（64.25±12.19）（P<0.001）.BALF total protein concentration was lower in group E（147.42±13.28）than in L（199.17±19.84）（P<0.001）.7.The ethanolic extract of Euphorbia thymifolia L.decreased TLR4protein expression in rats.Compared with the N group（0.526±0.028）,LPS increased the protein expression of TLR4;compared with the L（1.114±0.058）group,the ethanolic extract of P.millefolia decreased the protein expression of TLR4.8.The ethanolic extract of Euphorbia thymifolia L.reduced MPO activity levelsCompared with group N（0.334±0.017）,the MPO activity level in lung tissue of group L（1.153±0.129）was significantly increased（P<0.001）,and compared with group L,the MPO activity level in lung tissue of group E（0.890±0.061）was significantly decreased（P<0.001）.ConclusionThe ethanolic extract of Euphorbia thymifolia L.has a protective effect against LPS-induced acute lung injury. |
