TDK conference 2024

The treatment of chronic inflammatory enteropathy (CIE) in dogs is one of the major challenges of modern veterinary medicine. The disease causes chronic inflammation in the intestinal tract, which can lead to long-term damage to the intestinal barrier, the circulation of bacterial endotoxins (LPS) and the development of endotoxemia, further worsening the chronic inflammatory processes. Various antibiotics and immunosuppressive agents are used to treat CIE, but these agents have several side effects, and the use of antibiotics also contributes to the spread of antibiotic resistance. The aim of our experiments was to search for medicinal compounds that could be considered as complementary agents in the treatment of CIE in the future. The antimicrobial, anti-inflammatory and antioxidant effects of flavonoids, which are polyphenolic compounds, are well-documented in the literature. In our in vitro studies, we selected quercetin, luteolin and grape seed proanthocyanidins as the active compounds belonging to this group of compounds.

First, we isolated peripheral blood mononuclear cells (PBMC) from a healthy dog and then induced inflammation and oxidative stress in the culture by using LPS of Escherichia coli origin to model endotoxemia. Cell cultures were also treated with quercetin, luteolin and grape seed proanthocyanidin alone and in combination with LPS. Polyphenols were applied at concentrations of 25 and 50 μg/ml. Cell viability was assessed by the CCK-8 assay, reactive oxygen species (ROS) by the DCFH-DA assay, and tumour necrosis factor-α (TNF-α) was determined from cell supernatants by ELISA.

Our experiments have demonstrated that quercetin, luteolin and grape seed proanthocyanidins significantly reduce intracellular ROS concentrations in vitro at concentrations of 25 and 50 μg/ml compared to the LPS-treated group. When TNF-α concentrations were examined, we found that only luteolin at 25 and 50 μg/ml significantly reduced TNF-α elevated during inflammation compared to the LPS-treated group.

In conclusion, quercetin, luteolin and grape seed proanthocyanidin may be promising supplementary compounds in the future for the treatment of chronic inflammatory bowel disease in dogs in small animal medicine. However, further in vitro and in vivo studies are needed to confirm our results before clinical use.