Changes in the Neurochemical Characterization of Enteric Neurons in the Porcine Duodenum After Administration of Low-Dose Salmonella Enteritidis Lipopolysaccharides
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Lipopolysaccharides (LPS), also known as lipoglycans or endotoxins, form part of the outer membrane of Gram-negative bacteria. Previous studies have described the various harmful impacts of LPS on humans and animals. Nevertheless, many aspects of these effects are still not fully explained. One of them is the influence of endotoxins on the neurochemical characterization of neurons within the enteric nervous system (ENS), which is found in the intestinal wall and plays important adaptive roles during pathological processes and exposures. In this study, the impact of a low single dose of Salmonella Enteritidis LPS on the duodenal enteric neurons immunoreactive to substance P (SP), vasoactive intestinal polypeptide (VIP), pituitary adenylate cyclase activating peptide (PACAP-27), and cocaine- and amphetamine-regulated transcript (CART) was studied using a double immunofluorescence technique. During the study, it was shown that even a low dose of LPS affects the number of enteric neurons containing the neuropeptides studied, and these changes were dependent on the type of the enteric plexus. The most visible changes concerned the SP-like immunoreactive (LI) neurons in the outer submucous plexus (LPS caused an increase in the percentage of these neurons from15.74 ± 0.61 to 21.72 ± 0.79%). Furthermore, the VIP-LI neurons in the inner submucous plexus were seen to decrease from 12.64 ± 0.83 to 5.96 ± 0.58%. The mechanisms behind these noted fluctuations are not clear, but it may be connected with the pro-inflammatory and neurotoxic activity of LPS.
KeywordsPig Swine Endotoxins VIP CART PACAP SP
Publication was funded by KNOW (Leading National Research Centre) Scientific Consortium “Healthy Animal-Safe Food”, decision of Ministry of Science and Higher Education No. 05-1/KNOW2/2015 and statutory grant No. 25.610.001-300 from the Faculty of Medical Sciences, the University of Warmia and Mazury in Olsztyn in Poland.
Compliance with Ethical Standards
Conflict of Interest
The authors declare that they have no conflict of interest.
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