Protective Effect Of Mung Bean Oligopeptides On Lipopolysaccharide-induced Acute Lung Injury In Mice

Mung bean peptides are a kind of food-derived peptides with many biological functions such as anti-oxidation,blood pressure lowering and immunity enhancement.Mung bean oligopeptides are small molecule active peptides with wider physiological functions.However,there are few reports on the anti-inflammatory effects of mung bean peptides and mung bean oligopeptides.In this study,lipopolysaccharide was used as an inducer to construct macrophage RAW264.7 inflammation model and acute lung injury mouse model.The anti-inflammatory effects of mung bean oligopeptides on mice with acute lung injury were demonstrated by comprehensive in vitro and in vivo experiments,and initially explore its possible protection mechanisms.First,the mung bean oligopeptides(MBO)were used in lipopolysaccharide(LPS)-induced macrophage RAW264.7 inflammatory response to observe whether it inhibited the produced inflammation.The proliferation ability of macrophages was detected by WST-1 method.The phagocytic ability of macrophages was detected by neutral red method.The activity of myeloperoxidase(MPO),lactate dehydrogenase(LDH)and the amount of reduced glutathione(GSH)in macrophages were detected by kit method.The secretion of cytokines tumor necrosis factor-?(TNF-?),interleukin-1?(IL-1?),and interleukin-6(IL-6)in macrophages was detected by ELISA.The results showed that MBO significantly attenuated the inhibitory effect of LPS on macrophage proliferation and down-regulated its phagocytic ability(p<0.05).MBO significantly improved the levels of MPO,LDH,and GSH secreted by macrophages(p<0.05).MBO can significantly inhibit the increase of the secretion levels of pro-inflammatory cytokines TNF-?,IL-1?,and IL-6.The results of cell assay showed that MBO can attenuate LPS-induced macrophage inflammation by regulating macrophage phagocytosis,intracellular enzymatic digestion and reducing the secretion of pro-inflammatory cytokines,indicating that MBO has certain anti-inflammatory activity.To further verify the anti-inflammatory effects of mung bean oligopeptides on mice with acute lung injury,the mouse model of acute lung injury was constructed by intranasal instillation of LPS in the exprienment.After 5 h,the pathological changes of lung tissue were observed by HE staining,the wet weight to dry weight ratio(W/D)was measured by weighing method,the MPO activity in lung tissue was detected by spectrophotometry,the cytokine content in bronchoalveolar lavage fluid(BALF)was detected by ELISA,the protein concentration of BALF was detected by BCA method,the neutrophil count in BALF was detected by Wright-Giemsa staining.The results showed that MBO could attenuate lung injury,reduce the protein concentration of BALF and pro-inflammatory cytokines,reduce the number of neutrophils in BALF,and reduce the wet/dry weight ratio and MPO activity of lung tissue.The test results further prove that the mung bean oligopeptides have an anti-inflammatory effect.And it is speculated that mung bean oligopeptides exert their protective effect on acute lung injury by reducing pulmonary edema and pulmonary microvascular leakage,improving pathological changes of lung tissue,reducing neutrophil infiltration in BALF,and inhibiting the secretion of cytokines by inflammatory cells.This study initially confirmed the anti-inflammatory effect of mung bean oligopeptides and found that it has a protective effect on mice with acute lung injury.