Aims

The main objective of the present study was to assess and compare the safety and inhibitory efficacy of Lactobacillus acidophilus against cholera toxin and shigatoxin production by measuring CTX-B and Stx1 expression level in Caco-2 cells exposed to Vibrio cholerae (as a non-invasive small intestine pathogens and Shigella dysenteriae (as an invasive colon pathogen).

Methods

Caco-2 cells were incubated with L. acidophilus 2 h before infection by V. cholerae and S. dysenteriae. Following RNA extraction and cDNA synthesis, relative toxins mRNA levels were determined according to a comparative critical threshold (Ct) real-time PCR. L. acidophilus didn't show any cytotoxic effect on Caco-2 cells.

Results

L. acidophilus revealed a protective effect for Caco-2 cells against S. dysenteriae and V. cholera by 51% and 57%, respectively, which was determined by MTT assay and further confirmed by morphological examination. Pretreatment of Caco-2 cells with L. acidophilus prior to exposure to V. cholerae, attenuated the CTX-B expression in V. cholerae to about 1.76 folds. Expression of Stx1 by S. dysenteriae was also down-regulated to 1.6 folds following pretreatment of Caco-2 cells by L. acidophilus. No significant difference was observed in the attenuator role of L. acidophilus in toxin production by S. dysenteriae as a colon-invasive bacterium, compared with V. cholerae, the non-invasive pathogen of small intestine.

Conclusions

The results of the present study suggest that L. acidophilus is safe with protective effect for human epithelial colorectal cells, and is effective enough to be applied as a supplementary treatment for attenuation of toxin production in acute infectious diarrhea caused by V. cholerae and S. dysenteriae.

中文翻译：

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肠上皮细胞感染后，嗜酸乳杆菌减弱了霍乱弧菌和痢疾志贺氏菌的毒素产生

目的

主要目的本研究的是评估和比较的安全性和抑制功效嗜酸乳杆菌通过测量抗霍乱毒素和shigatoxin生产CTX-B和STX1表达水平在暴露于Caco-2细胞霍乱弧菌（作为一种非侵入性小肠病原体和痢疾志贺氏菌（作为侵袭性结肠病原体）。

方法

将Caco-2细胞与嗜酸乳杆菌孵育2小时，然后再感染霍乱弧菌和痢疾链球菌。RNA提取和cDNA合成后，根据比较关键阈值（Ct）实时PCR确定相对毒素mRNA水平。嗜酸乳杆菌对Caco-2细胞没有任何细胞毒性作用。

结果

嗜酸乳杆菌显示出对Caco-2细胞针对痢疾链球菌和霍乱弧菌的保护作用分别为51％和57％，这通过MTT测定确定并通过形态学检查进一步证实。Caco-2细胞用的预处理嗜酸乳杆菌在暴露于霍乱弧菌，减毒的CTX-B在表达霍乱弧菌至约1.76倍。在嗜酸乳杆菌预处理Caco-2细胞后，痢疾链球菌Stx1的表达也下调至1.6倍。没有观察到嗜酸乳杆菌的衰减作用有显着差异痢疾链球菌作为结肠侵袭性细菌产生的毒素，与霍乱弧菌相比，霍乱弧菌是小肠的非侵袭性病原体。

结论

本研究的结果表明，嗜酸乳杆菌对人上皮结肠直肠细胞具有安全保护作用，并且足以有效地作为补充疗法来减轻霍乱弧菌和霍乱弧菌引起的急性感染性腹泻的毒素产生。痢疾。