| Acute lung injury is a serious clinical syndrome characterized by pulmonary edema and inflammation caused by various lung disease processes.Despite significant progress in the prevention of acute lung injury,it is still prone to develop into acute respiratory distress syndrome.Donkey milk is rich in lysozyme,lactoferrin,immunoglobulin,and biologically active peptides,which have anti-inflammatory,antibacterial,and anti-tumor activities.The famous Tibetan medical work "Four Medical Classics" records the formula for treating lung disease with donkey milk.Donkey whey protein contains rich bioactive proteins,but there are few reports on the protection of whey protein against acute lung injury in mice.This study measured the antioxidant capacity of whey protein through in vitro simulated digestion,established an acute lung injury model using lipopolysaccharide,and explored the protective effect of whey protein on acute lung injury in mice from the aspects of inflammatory response and oxidative stress.The following results were obtained:(1)The antioxidant capacity of whey protein before and after digestion was evaluated by the indicators of ABTS,DPPH,hydroxyl free radical and reducing power,and it was found that the whey protein digestion product after enzymatic hydrolysis by pepsin and trypsin had stronger antioxidant capacity than whey protein at the same concentration,and when the concentration of whey protein and whey protein digested product was 8 mg/m L,the ABTS clearance was(24.40%±1.46%)and(40.07%±1.04%),respectively;The DPPH clearance was(30.51%±1.64%)and(50.22%±1.49%),and the hydroxyl radical scavenging rate was(49.36%±1.42%)and(68.49%±1.58%);The reducing power is(0.373±0.018)and(0.571±0.024),and the test results prove that the antioxidant capacity of whey protein can be improved under the action of enzymes through in vitro simulated digestion.(2)The results showed that when the concentration of lipopolysaccharide was 5 mg/kg,the indicators of lung tissue wet dry weight,IL-10,TNF-α,spleen index and MPO activity were higher than those in the2.5 mg/kg group,and there were significant differences(P<0.05),indicating that when the lipopolysaccharide concentration was 5 mg/kg,the acute lung injury induced by the mouse model was more serious,and no death occurred during the experiment,which provided a suitable animal model for subsequent research.(3)To explore the protective effect of donkey whey protein on mice with acute lung injury,60 male mice in Kunming were randomly divided into 6 groups,namely CK group,LPS group,DEX group and DWP(125,250,500 mg/kg).27 days before modeling,the DWP group gave mice low,medium and high doses of donkey whey protein by gavage,and the mice in other groups were gavaged with the same volume of normal saline,and 5mg/kg lipopolysaccharide was injected intraperitoneally on the 28 th day to model and the mice were dejuvenated and sacrificed for 8 h.The results showed that the wet/dry weight,IL-10,TNF-α,spleen index,MPO activity,protein content,MDA and SOD of lung tissues in each group showed that the wet/dry weight,IL-10,TNF-α,spleen index,MPO activity,protein content and MDA of lung tissues in DWP group were significantly lower than those in LPS group(P<0.05),while SOD activity was significantly higher than that in LPS group(P<0.05),and the results showed that donkey whey protein could protect mice with acute lung injury by regulating inflammatory response and oxidative stress level.In this paper,whey protein was extracted from donkey milk,and its antioxidant capacity was studied by simulated digestion in vitro,and lipopolysaccharide was used to induce it Kunming male mice were guided to establish an acute lung injury model,and the results showed that donkey whey protein had a certain protective effect on mice with low,medium and high doses of whey protein by gavage,and lung tissue wet/dry weight,IL-10,TNF-α,spleen index,MPO activity,protein content,MDA and SOD were used as detection indicators,and the results showed that donkey whey protein had a certain protective effect on mice with acute lung injury,which provided theoretical support for the development and utilization of donkey whey protein in the later stage. |
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