FOOD SCIENCE ›› 2020, Vol. 41 ›› Issue (19): 191-197.doi: 10.7506/spkx1002-6630-20191110-108

• Nutrition & Hygiene • Previous Articles     Next Articles

Effect of Lactobacillus acidophilus on Regulating the Production of Immune Factors in HT-29 Cells under Initial Weak Acidic and Alkaline Conditions

ZHANG Qiuyue, WANG Gang, CHEN Kunpeng, PAN Daodong, ZENG Xiaoqun, WU Zhen, GUO Yuxing   

  1. (1. Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, School of Food and Pharmaceutical Sciences, Ningbo University, Ningbo 315211, China; 2. School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210097, China)
  • Online:2020-10-15 Published:2020-10-23

Abstract: In order to investigate the immunomodulatory effects of Lactobacillus acidophilus on human intestinal cells, Lactobacillus acidophilus, showing different adhesion characteristics when cultured at pH 5.5 and 7.5, were co-cultured with human colon cancer HT-29 cells, and the changes of immune factors in HT-29 cells were determined. The relative gene expression levels of heat shock protein (Hsp) 70, interleukin (IL)-8, IL-10, nuclear factor κB (NF-κB), Toll-like receptor 4 (TLR-4) and tumor necrosis factor-α (TNF-α) were detected by reverse-transcription quantitative real-time polymerase chain reaction (RT-qPCR), and enzyme-linked immunosorbent assay (ELISA) was applied to determine the protein expression levels of IL-8, IL-10 and TNF-α. RT-qPCR results showed that after the co-cultivation of HT-29 cells and Lactobacillus acidophilus at either pH, at the transcriptional level, Hsp70 and TNF-α were significantly up-regulated, while IL-8, NF-κB and TLR-4 were significantly down-regulated when compared with the blank control cells without the presence of Lactobacillus acidophilus (P < 0.01). The gene expression levels of Hsp70, IL-10 and TNF-α were significantly up-regulated in the pH 7.5 group when compared with the pH 5.5 group; meanwhile, NF-κB and TLR-4 were significantly down-regulated (P < 0.05). The ELISA results showed that under both pH conditions, the TNF-α expression level in HT-29 cells was significantly higher than that in the blank control group, while the concentration of pro-inflammatory factor IL-8 was significantly decreased; the anti-inflammatory factor IL-10 in the pH 7.5 group was significantly higher than that in the pH 5.5 group (P < 0.01). In summary, Lactobacillus acidophilus under weak acidic and weak alkaline intestinal conditions can promote the immunity of intestinal cells, and the weak alkaline condition with pH 7.5 is more effective than the weak acidic intestinal environment with pH 5.5, which can significantly enhance the immunoregulatory effect of Lactobacillus acidophilus on the intestinal tract, thereby helping maintain intestinal health.

Key words: Lactobacillus acidophilus; HT-29 cells; immune factors; reverse transcription quantitative real-time polymerase chain reaction; enzyme-linked immunosorbent assay

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