Study On Endotoxin-induced Acute Lung Injury And Antagonizing Effects Of ω-3 Fish Oil Emulsion In Rabbits

Objective:To explore whether theω-3 fish oil emulsion have protective effects on rabbits with endotoxin-inducing acute lung injury of rabbits and to study the mechanism.Methods:24 New Zealand rabbits were randomly divided into 3 groups with 8 rabbits each:control group(groupA),ET treatment group(group B) and combination group(treated by ET andω-3 fish oil emulsion,group C).The rabbits of group C receivedω-3 fish oil emulsion 5 ml/kg.d(hour ofⅣ＞6h) two days before surgery,the rabbits of group B,C induced by intravenous injection of ET(700μg/kg) by jugular vein and group C receivedω-3 fish oil emulsion 5 ml/kg(hour ofⅣ＞6h) once again before injection of ET.During the experiment, respiratory rates,arterial blood gases were measured at Oh,0.5h,2h,4h respectively then,After all rabbits were killed at 4h,the contents of TNF-α,MPO,IL-10,TXB₂ and 6-keto-PGF_1α in pulmonary tissue were measured and the pathologic changes of pulmonary tissue were examined and scored down with lightmicroscope,and the lung wet/dry(W/D)and the lung water content were measured also.Results:In comparing with group A,group B showed typical characters of ALI at 0.5h after injection of LPS,including the increase in respiratory rates,and heart rate,and decrease of oxygen saturation index(PaO₂/FiO₂),group C showed PaO₂/FiO₂ decreased,rspiratory rates and heart rate increaing also,but conditions were better than those in group B,and there are no significant difference between the group A and C.in comparing with group A the pathological examination of group B Showed obviously injury in pulmonary tissue,scores,W/D,the lung water content stepped up significantly(p＜0.05),those change of group C showed slightly than group B;compared with group A,C,contents of TNF-αof group B stepped up significantly (P＜0.05),group B have a increasing trend(40.249 VS 36.945)compared with group C,but there are no significant between the two group,contents of IL-10 of group B,C increased significantly than group A(P＜0.05),group C have a increasing trend(48.583 VS 44.436),but there are no significant compared with group B.contents of MPO of group C stepped up significantly than group A,but stepped down significantly than group B.Compared with group A,rabbits of group B showed the contents of TXB₂ and 6-keto-PGF₁αin pulmonary tissue increasing,the rate of TXB₂/6-keto PGF₁αincreased significantly,the group C tissue increaing also,but conditions were better than those in group B,the rate of TXB₂/6-keto PG- F₁αdecreased significantly than groupResults:ω-3 fish oil emulsion can down-regulate the contents of TNF-α,the rate of TXB₂/6-keto PGF₁αin pulmonary tissue in pulmonary tissue,reduce recruitmentin of PMN have the trend of up-regulate the contents of IL-10,which exert protective effects on ET-induced early ALI in rabbits to some extent.