牛奶外泌体促进新生幼鼠免疫系统发育的研究

Milk exosomes promoting neonatal mice immune system development

目的 探讨牛奶外泌体对新生幼鼠免疫系统的影响。方法 超高速离心法分离并鉴定牛奶外泌体,酶联免疫吸附试验(enzyme-linked immunosorbent assay, ELISA)检测牛奶外泌体中免疫球蛋白G(immunoglobulin G, IgG)、免疫球蛋白A(immunoglobulin A, IgA)、免疫球蛋白M(immunoglobulin M, IgM),转化生长因子-β(transforming growth factor-β, TGF-β)和表皮生长因子(epidermal growth factor, EGF)浓度;36只7日龄KM新生幼鼠随机分为母乳组、奶粉组和奶粉+牛奶外泌体组,每组12只,连续喂养14 d。分别在第7天和第14天各处死6只KM幼鼠,收集血液进行血常规检测,ELISA检测血清中IgG、IgA、IgM、TGF-β和EGF浓度。结果 ELISA结果表明牛奶外泌体中含有IgG、IgA、IgM、TGF-β和EGF。相较母乳组和奶粉+牛奶外泌体组,奶粉组第7天和第14天幼鼠血清IgG、IgA、IgM的浓度均明显降低(P<0.05)。与奶粉组对比,奶粉+牛奶外泌体组幼鼠血清IgG、IgA、IgM的浓度均显著性升高(P<0.05)。TGF-β和EGF的含量变化不明显。血常规结果表明奶粉组的血红蛋白和平均血红蛋白浓度显著降低(P<0.05),红细胞比容和血小板显著上升(P<0.05),奶粉+外泌体组淋巴细胞百分比显著下降(P<0.05),粒细胞百分比显著升高(P<0.05)。结论 牛奶外泌体中含有IgG、IgA、IgM、TGF-β和EGF,且能促进奶粉喂养幼鼠的免疫因子表达,增强新生幼鼠的免疫能力。

Objective To investigate the effects of milk exosomes in immune system of neonatal mices.Methods Separation and identification of milk exosomes using high-speed centrifugation,and detection of immunoglobulin G(IgG),immunoglobulin A(IgA),immunoglobulin M(IgM),transforming growth factor-β(TGF-β),and epidermal growth factor(EGF)concentrations in milk exosomes using enzyme-linked immunosorbent assay(ELISA);367-day-old KM newborn mice were randomly divided into a breast milk group,a formula milk group,and a formula milk+milk exosomes group,with 12 mice in each group,and fed continuously for 14 days.Six KM mice were euthanized on the 7th and 14th day respectively,and blood samples were collected for routine blood tests.ELISA was used to detect the concentrations of IgG,IgA,IgM,TGF-β,and EGF in the serum.Results ELISA results showed that milk exosomes contained IgG,IgA,IgM,TGF-βand EGF.Compared with the breast milk group and the milk+milk exosome group,the concentrations of serum IgG,IgA and IgM in the milk group were significantly decreased on day 7 and day 14(P<0.05).Compared with milk group,serum IgG,IgA and IgM concentrations in milk+milk exosome group were significantly increased(P<0.05).The contents of TGF-βand EGF were not significantly changed.The blood routine results showed hemoglobin(HGB)and red blood cell(RBC)in milk group were significantly decreased(P<0.05),mean corpuscular hemoglobin concentration(MCHC)and platelet(PLT)were significantly increased(P<0.05),LYM in milk+exosome group was significantly decreased(P<0.05),GRA was significantly increased(P<0.05).Conclusion Milk exosomes contain IgG, IgA, IgM, TGF-β, and EGF, and can promote the expression of immune factors in infant mice fedwith milk powder, enhancing the immune ability of newborn mice.