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目的:评价不同铁饱和度的乳铁蛋白对葡聚糖硫酸钠(DSS)诱导的小鼠溃疡性结肠炎的作用。方法:动物试验全程21 d,雄性BALB/c小鼠随机分成4组,即:正常组、模型组、低铁乳铁蛋白(Apo-LF)组和高铁乳铁蛋白(Holo-LF)组。14~21 d时,模型组、Apo-LF组和Holo-LF组小鼠饮用含2.5%DSS的饮用水7 d,诱导小鼠形成溃疡性结肠炎模型。在第21天时处死小鼠。通过炎症相关指标评价各组小鼠的反应,结果:Apo-LF组与模型组和Holo-LF相比,疾病活动指数(DAI)、结肠缩短量、组织病理学评分显著降低。结肠组织中促炎因子表达量、肠道中脂多糖(LPS)浓度、革兰氏阴性菌菌落数显著降低。而Holo-LF组与模型组相比各项指标均无显著性差异。结论:不同铁饱和度的乳铁蛋白对DSS诱导的溃疡性结肠炎的治疗效果不同。Apo-LF能显著缓解溃疡性结肠炎症状,而Holo-LF无明显效果。这与不同铁饱和度的LF对促症因子,LPS,革兰氏阴性菌的影响不同有关。 相似文献
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乳铁蛋白和乳铁素的抗菌活性比较 总被引:2,自引:1,他引:2
牛乳铁蛋白是从牛乳中提取出来的一种铁结合性糖蛋白,牛乳铁素是从牛乳铁蛋白N-端水解下来的25个氨摹酸残荩。它们具有多种乍物学功能,其中的广谱抗菌性尤为引人注目。本实验以牛初乳中提取的乳铁蛋白及其水解产物乳铁素为研究对象,选取大肠杆菌为实验菌株,进行铁饱和乳铁蛋白和缺铁性乳铁蛋白、乳铁素对大肠杆菌生长抑制的比较研究。研究结果表明:铁饱和乳铁蛋白、缺铁性乳铁蛋白和乳铁索的最小抑菌浓度分别为6mg/ml、3mg/ml和15μg/ml,乳铁素的最小杀菌浓度为30μg/ml。乳铁蛋白水解后,经纯化获得的乳铁素,其抗菌能力较缺铁性乳铁蛋白增加200倍,较铁饱和乳铁蛋白增加400倍。 相似文献
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《Journal of dairy science》2022,105(6):4791-4803
Infant intestinal development is immature and, thus, is vulnerable to bacterial and viral infections, which damage intestinal development and even induce acute enteritis. Numerous studies have investigated that lactoferrin (LF) has protective effects on the intestine and may play a role in preventing intestinal inflammation in infants. Lactoferrin is divided into 2 types, namely apo-LF and holo-LF, depending on the degree of iron saturation, which may affect its bioactivities. However, the role of LF iron saturation in protecting infant intestinal inflammation has not been clearly clarified. Therefore, in this study, young mice models with intestinal damage induced by lipopolysaccharides (LPS) in vivo and primary intestinal epithelial cells in vitro were constructed to enteritis injury in infants for investigation. The apo-LF and holo-LF were subsequently applied to the mouse models to investigate and compare their levels of protection in the intestinal inflammatory injury, as well as to identify which LF was most active. Moreover, the specific mechanism of the LF with optimal iron saturation was further investigated through Western blot assay. Results demonstrated that disease activity index, shortened length of colon tissue, and histopathological score were significantly decreased in the apo-LF group compared with those of the LPS group and the holo-LF group. In the apo-LF group, the concentration of LPS in the intestinal tract and the number of gram-negative bacteria colonies decreased significantly and the expression levels of proinflammatory factors in the colon tissue were downregulated, in comparison with those in the LPS group. The findings of this study thus verify that apo-LF can significantly alleviate enteritis injury caused by LPS, through regulating the PPAR-γ/PFKFB3/NF-κB inflammatory pathway. 相似文献
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This study aimed to determine the effect of thermal treatments on the recovery of lactoferrin in whey coming from rennet-coagulated skim milk. The impact of lactoferrin iron saturation was also assessed using skim milk spiked with different lactoferrin iron forms. The recovery of lactoferrin in the rennet whey fraction was determined by reverse-phase HPLC. One- and 2-dimensional sodium dodecyl sulfate PAGE analyses were performed on rennet curds to characterize the protein interactions involving lactoferrin in heated milk. The extent of lactoferrin recovered in the whey fraction was found to reduce as the heating temperature increased. The binding of iron by lactoferrin improved its thermal stability and its recovery in the whey fraction. Poly-acrylamide gel electrophoresis results showed that the association of lactoferrin in the unheated milk rennet curd involved noncovalent interactions, whereas upon heating, lactoferrin also interacted via an intermolecular disulfide link. Depending on the severity of the heat treatment, lactoferrin aggregates with Cys-containing proteins (β-lactoglobulin, α-lactalbumin, αs2-casein, and κ-casein) occurred by intermolecular thiol/disulfide exchange reactions. These noncovalent and covalent interactions explained the lower recovery of lactoferrin in heated milk. 相似文献
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卵转铁蛋白(Ovotransferrin,OVT)和乳铁蛋白(Lactoferrin,LF)经不同温度(5090℃)处理后,通过圆二色性分析比较其二级结构的变化,紫外吸收和表面疏水性分析比较其空间构象的变化,SDS-PAGE分析比较其分子的聚集,溶解度分析比较其功能的变化。结果表明,5060℃时,OVT和LF的理化特性均无明显变化。70℃时,OVT和LF的紫外吸光值均明显增大;8090℃时,OVT的紫外吸光值不再进一步增大,而LF的进一步逐渐增大。7090℃时,OVT和LF的表面疏水性指数均明显增大;LF的表面疏水性指数远大于OVT的,但OVT的增大程度较LF的更大。7090℃时,OVT和LF的α-螺旋含量均明显降低,β-折叠和无规卷曲含量均明显升高,且OVT的二级结构组分的变化程度较LF的更大。7090℃时,OVT和LF的SDS-PAGE图谱中的主要蛋白条带密度均明显降低;相同温度下,OVT的降低程度较LF的更大。7090℃时,OVT和LF的溶解度均明显降低;相同温度下,OVT的降低程度较LF的更大。总之,OVT和LF的结构和功能在加热时均发生改变,但OVT的变化程度较LF的更大。 相似文献
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乳铁蛋白的功能特性及其在婴儿配方奶粉中的应用 总被引:6,自引:0,他引:6
介绍了母乳中乳铁蛋白的功能特性,及其应用在婴儿配方奶粉中对非母乳喂养婴儿营养的重要性,国外有关乳铁蛋白在婴幼儿配方奶粉中的应用情况。探讨了乳铁蛋白在婴儿配方奶粉中应用的研究过程,包括有关配方设计依据、使用的原料、生产工艺流程、检验方法、检验结果等。 相似文献
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Noppe W Vanhoorelbeke K Galaev IY Mattiasson B Deckmyn H 《Journal of dairy science》2004,87(10):3247-3255
Linear pentadecamer and cyclic hexamer peptide phage libraries were used to isolate phage clones with binding affinity toward lactoferrins purified from human and bovine milk. Phage clones with high specificity toward lactoferrin were selected with different binding strengths depending on the sequence of the peptide displayed by the phage. Phages coated to a microtiterplate were able to capture lactoferrin from crude milk samples without prior treatment. One of the selected sequences, EGKQRR, failed to bind to lactoferrin. In contrast, a branched tree-peptide bearing 4 EGKQRR sequences did bind to lactoferrin (Kd approximately 29 microM) and was also capable of inhibiting the binding of the phage to lactoferrin (IC(50) approximately 17 microM), indicating that avidity was important. Unexpectedly, the affinity of the phage for lactoferrin was influenced by the amount of bound Fe(3+), with a much lower affinity when lactoferrin was saturated with Fe(3+) as compared with the iron-depleted or partially saturated (natural) lactoferrin. As the phage does not bind to the Fe(3+)-binding site, the difference in binding affinity is due to differences in conformation of lactoferrin induced by Fe(3+). These results demonstrate that avidity or multipoint attachment and Fe(3+)-induced conformational changes play an important role in the binding of the selected phage to lactoferrin. Thus, we could demonstrate that, by the use of selected phage clones, we are able not only to detect lactoferrin, but also to capture lactoferrin from crude milk samples. Furthermore, the extent of phage binding provides additional information about the iron content and the concomitant conformation of lactoferrin. 相似文献
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J.L. Zhang X. Han Y.J. Shan L.W. Zhang M. Du M. Liu H.X. Yi Y. Ma 《Journal of dairy science》2018,101(3):1827-1833
We conducted a comparative in vitro study on the proliferative effects of natural human lactoferrin (nhLF) and bovine lactoferrin (bLF) on osteoblasts. We investigated cell proliferation, cell survival, cell cycle, and mRNA and protein expression of proliferating cell nuclear antigen. Results indicated that treatment with 100 μg/mL of bLF or nhLF promoted the proliferation and sustenance of osteoblasts, and increased the length of the G2/M and S phases compared with the untreated osteoblasts. Results of real-time quantitative PCR and Western blot showed that mRNA and protein expression of proliferating cell nuclear antigen by osteoblasts treated with bLF or nhLF were greater than those of the untreated control. At the same concentration, bLF demonstrated a greater effect on osteoblast proliferation than did nhLF. This study provides insights of significance in the utlization of bLF in healthy food formulas. 相似文献
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H.Y. Li H.G. Yang H.M. Wu Q.Q. Yao Z.Y. Zhang Q.S. Meng L.L. Fan J.Q. Wang N. Zheng 《Journal of dairy science》2021,104(7):7383-7392
This study tested the ability of lactoferrin to modulate pulmonary inflammation. To construct in vitro and in vivo inflammatory lung models, cells from the human lung adenocarcinoma cell line (A549) were exposed to lipopolysaccharide (LPS, 1 µg/mL), and mice (CD-1) were intratracheally administered LPS [10 mg/kg of body weight (BW), tracheal lumen injection], respectively. The A549 cells were preincubated with lactoferrin (10 mg/mL), and the mice were intraperitoneally injected with lactoferrin (100 mg/kg of BW), followed by LPS treatment. The concentrations of proinflammatory cytokines (IL-1β and TNF-α) in culture medium of A549 cells and in bronchoalveolar lavage fluid of the mice were determined using enzyme-linked immunosorbent assays. The toll-like receptor 4–related pathway (TLR4/MyD88/IRAK1/TRAF6/NFκB) was determined at gene and protein expression levels in A549 cells and mouse lung tissue. Results showed that LPS treatment significantly elevated the concentrations of IL-1β and TNF-α in the A549 cell culture medium and in bronchoalveolar lavage fluid of the mice; it also elevated both the mRNA and protein expressions of TLR4 and the TLR4 downstream factors in A549 cells and mouse lung tissue. Nevertheless, lactoferrin apparently depressed the releases of IL-1β and TNF-α from A549 cells and lung tissues stimulated by LPS, and significantly suppressed the TLR4 signaling pathway. Lactoferrin also promoted the enhancement of miR-146a expression in A549 cells and mouse lung tissue. Moreover, 100°C heating for 3 min caused total loss of the previously listed bioactivity of lactoferrin. Collectively, we proved that lactoferrin intervened in LPS-induced inflammation in the pulmonary cell model and in the mouse model, through inhibiting the TLR4-related pathway. 相似文献