The aim of this study was to investigate the probiotic properties of 174 Lactobacillus strains isolated from Mongolian dairy products, and particularly their impact on intestinal calcium uptake and absorption. All isolates underwent a first screening based on cell surface hydrophobicity, acid tolerance, tolerance to gastro-intestinal digestion, autoaggregation, adhesion and cytotoxicity against intestinal cells. Six Lactobacillus strains from different species (L. casei, L. kefiranofaciens, L. plantarum, L. fermentum, L. helveticus and L. delbrueckii) were selected, and their impact on intestinal calcium uptake and transport was investigated using Caco-2. Five strains were able to improve total calcium transport after 24h contact with a differentiated Caco-2 cell monolayer. Concomitantly the L. plantarum strain was able to increase cellular calcium uptake in Caco-2 cells by 10% in comparison to control conditions. To determine which pathway(s) of calcium absorption was modulated by the strains, a qPCR-based study on 4 genes related to calcium/vitamin D metabolism or tight junction integrity was conducted on mucus-secreting intestinal HT-29 MTX cells. The L. plantarum strain modulates the transcellular pathway by regulating the expression of vitamin D receptor (1.79 fold of control) and calcium transporter (4.77 fold of control) while the L. delbrueckii strain acts on the paracellular pathway by modulating claudin-2 expression (2.83 fold of control). This work highlights the impact of Lactobacillus probiotic strains on intestinal calcium absorption and for the first time give some evidence about the cellular pathways involved

这项研究的目的是调查从蒙古乳制品分离的174株乳酸杆菌菌株的益生菌特性，尤其是它们对肠道钙吸收和吸收的影响。根据细胞表面的疏水性，耐酸性，对肠胃消化的耐受性，自身聚集性，粘附性和对肠细胞的细胞毒性，对所有分离株进行首次筛选。来自不同物种的六种乳酸杆菌菌株（干酪乳杆菌，kefiranofaciens乳杆菌，植物乳杆菌，发酵乳杆菌，helveticus和德氏乳杆菌），然后使用Caco-2研究它们对肠道钙摄取和运输的影响。与分化的Caco-2细胞单层接触24小时后，五株菌株能够改善总钙转运。同时，与对照条件相比，植物乳杆菌菌株能够将Caco-2细胞中的细胞钙摄取提高10％。为了确定菌株调节钙吸收的途径，在分泌粘液的肠道HT-29 MTX细胞上进行了基于qPCR的与钙/维生素D代谢或紧密连接完整性相关的4个基因的研究。该植物乳杆菌菌株通过调节维生素D受体（对照组的1.79倍）和钙转运蛋白（对照组的4.77倍）的表达来调节跨细胞途径，而德氏乳杆菌通过调节claudin-2的表达（对照组的2.83倍）来作用于旁细胞途径。 ）。这项工作强调了乳酸杆菌益生菌菌株对肠道钙吸收的影响，并首次为所涉及的细胞途径提供了一些证据