TDK conference 2020

In recent years, probiotics have established themselves as promising preventive medicine. This makes them not only valuable from a medical point of view, but also of great economic interest and thus they are in the focus of many research projects. Due to their numerous antipathogenic effects, they reduce the hazard of developing diseases. Thus, they are not only used in human medicine and the food industry but are also becoming increasingly important in modern animal husbandry as an alternative to the prophylactic administration of antibiotics. The site of action of probiotics is primarily the small intestine, but also the colon, therefore they can prevent intestinal dysbiosis by supporting the healthy intestinal microbiota and thus keeping the intestinal ecosystem in balance. From the intestine they are able to exert numerous beneficial effects.

The goal of our research was to investigate the effect of heat-inactivated Lactobacillus rhamnosus (LAB) on the intestinal inflammatory signaling pathway. In this study, we used an in vitro model of the intestinal epithelium. Non-tumorigenic porcine jejunal cells (IPEC-J2) were used in this study. The enterocyte cell cultures were treated with the LAB, which contains 10^9 Lactobacillus cells/ml, for 1, 3, 6 and 16 hours. From the treated and control cell cultures the IL-6, IL-8 and TNF-alpha mRNA levels were measured using quantitative PCR method, furthermore, IL-6 and IL-8 protein level were measured with ELISA method.

The IL-8 gene expression was upregulated after all LAB treatments. The TNF-alpha gene was upregulated by the 1- and 3-hour LAB treatments, but it was downregulated after 16 hours of LAB exposure. The IL-6 mRNA level was decreased after the 3- and 6-hour LAB treatments. At protein level, the LAB treatment increased the level of IL-8 and decreased the level of IL-6.

The results of qPCR and ELISA are consistent; the IL-6 decreased, and the IL-8 increased at both mRNA and protein levels. Overall, the heat-inactivated Lactobacillus rhamnosus exerts immunomodulatory effect on the intestinal epithelium at a density of 10^9 cells/ml.