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Home » Archive » 2011 » Veterinary Session

Veterinary session

Effect of bioactive metabolites of probiotics in prevention of gastrointestinal oxidative injury
Marosi András - year 4
Szent István University Faculty of Veterinary Science Department of Pharmacology and Toxicology
Supervisors: Dr. Pásztiné dr. Gere Erzsébet, Dr. Gálfi Péter

Abstract:

An essential role of antioxidant systems is that they counteract the harmful effects of reactive oxygen species. Oxidative stress is caused by changes in this delicate balance. It is associated with a wide range of diseases as underlying cause or predisposing factor. The intestinal oxidative stress, aside from its direct cell-damaging effect, induces the production of proinflammatory cytokines in enterocytes and causes lipid peroxidation in membranes. The therapeutical value of probiotics has been proven in the prevention of several intestinal inflammatory diseases and treatment of infections, however, the main driving force responsible for this anti-inflammatory effect remains to be elucidated.

The aim of our investigations was to reveal the influence of spent culture supernatant (SCS) of probiotics on the response of enterocytes to oxidative stress, and the SCS's ability to protect them from oxidative injury. Another goal was to find out which active components of the SCS can play a role in this beneficial effect. Our preliminary data indicated that probiotic strain Lactobacillus plantarum 2142 has the most promising protective effect against oxidative stress-induced inflammation. Therefore, we used its SCS in our experiments.

To determine the impact of probiotics in acute oxidative stress, the experiments were performed on IPEC-J2 in vitro intestinal epithelial cell line (cultured on collagen-coated polyester membrane inserts), which contains non-transformed enterocytes isolated from the jejunum of a neonatal piglet. We used hydrogen peroxide solution to provoke oxidative stress in cells.

We determined the relative gene expression of two inflammatory cytokines (IL-8 and TNF-α) and that of cytoprotective 70 kDa heat shock protein (Hsp70) in peroxide-treated IPEC-J2 cells using a quantitative real-time PCR method after addition of the SCS or its defined components (short chain fatty acids: acetic acid, and lactic acid).

According to our results, the SCS of Lactobacillus plantarum 2142 effectively reduced oxidative stress-induced inflammation: there was a significant decrease in the expression of IL-8 and TNF-α, while the gene-expression of Hsp70 increased significantly. Acetic and lactic acid produced by the probiotic strain could not reduce the expression of inflammatory cytokines. The production of Lactobacillus plantarum 2142-specific proteins of different molecular weights was ascertained from the SCS by two bioanalytical methods (SDS-polyacrylamide gel electrophoresis and capillary electrophoresis). These products may play key role in reducing the up-regulation of inflammatory cytokines and in the anti-inflammatory effect. In the future, our goals are to isolate active components present in the SCS of lactobacilli and to determine the type of processes behind protection against oxidative cell damage (signal transduction pathways and/or free radical scavenging effect).



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