Sessions

Canine chronic inflammatory enteropathy (CIE) is a multifactorial disorder characterized by gastrointestinal signs persisting for at least three weeks. Mucosal immune dysregulation, environmental triggers, genetic predisposition, and gut microbiome dysbiosis all play crucial roles in its pathogenesis. While dietary management forms the cornerstone of therapy, severe cases may require immunosuppressive agents. Natural bioactive compounds exhibiting anti-inflammatory and antioxidant properties represent promising adjunct therapeutic options; however, their evaluation requires reliable in vitro models of intestinal inflammation.

The objective of our study was to establish a stable and reproducible canine CIE model suitable for screening novel anti-inflammatory and antioxidant agents. For the experiments, duodenal explants were obtained during gastrointestinal endoscopic examinations in dogs. To determine the optimal cultivation period, tissue integrity was monitored over 12 hours via lactate dehydrogenase (LDH) activity assays and histopathological evaluation. Subsequently, bacterial lipopolysaccharide (LPS) stimulation assays were carried out under these optimized culture conditions.

To induce inflammatory pathways, explants were challenged with two E. coli- and two Salmonella-derived LPS preparations. The magnitude of the inflammatory response was evaluated by measuring extracellular H₂O₂ as well as TNF-α and IL-6 concentrations, while explant viability was monitored by assessing LDH release. To account for variations in biopsy fragment sizes, all experimental data were normalized to total protein content determined by the bicinchoninic acid (BCA) assay.

None of the LPS treatments significantly affected LDH activity. Extracellular H₂O₂ levels increased significantly upon Salmonella Typhimurium exposure. TNF-α production was significantly elevated following treatment with both S. Typhimurium and S. Enteritidis compared to the control, whereas a significant induction of IL-6 was observed exclusively in response to S. Enteritidis.

Our findings demonstrate that this in vitro explant culture system represents a reliable model for studying inflammatory processes in the canine intestinal mucosa. Salmonella-derived LPS elicited a more pronounced inflammatory response than E. coli LPS, proving to be a more effective stimulant in this experimental design. This established system offers a valuable platform for evaluating potential anti-inflammatory and antioxidant therapeutics.