Modulation of the main porcine enteric neuropeptides by a single low-dose of lipopolysaccharide (LPS) Salmonella Enteritidis

Anita Mikołajczyk,Dagmara Złotkowska,Sławomir Gonkowski

doi:10.1186/s13099-017-0225-6

Abstract

BackgroundThe present research was conducted to investigate the influence of a low, single dose of LPS, which does not result in any clinical symptoms of intoxication on the expression of selected neuropeptides within the intestines of the domestic pig.MethodsThis experiment was conducted on immature female pigs of the Pitrain × Duroc breed (n = five per group). Seven days after the intravenous injection of 10 mL saline solution for control animals and 5 μg/kg b.w. (in 10 mL saline solution) LPS Salmonella Enteritidis for the experimental group, the excised segments of duodenum, jejunum, ileum, ileocecal valve, caecum, descending colon, transverse colon, ascending colon and rectum were prepared to extract the main enteric neuropeptides, including GAL, NPY, SOM, SP, VIP.ResultsThe results of this research indicate that single low-dose LPS S. Enteritidis produced changes in the content of the selected neuropeptides of the porcine intestine. The most visible changes were observed in the transverse colon, where LPS induced the increase of GAL expression from 19.41 ± 7.121 to 92.92 ± 11.447 ng/g tissue.ConclusionThe exact functions of the substances studied and mechanisms of responses to LPS action depend on the sections of the intestines. The mechanisms of observed changes are not fully understood, but fluctuations in neuronal active substance levels may be connected with neurodegenerative and/or pro-inflammatory activity of LPS.

Highlights

The present research was conducted to investigate the influence of a low, single dose of LPS, which does not result in any clinical symptoms of intoxication on the expression of selected neuropeptides within the intestines of the domestic pig
Using the pig as a biomedical model which is phylogenetically closer to humans than rodents, plays a critical role in understanding the physiological and pathophysiological processes in the human body [18]. During this investigation, there were no differences in behavior, feeding habits or health status between animals of the control and experimental groups
The expression of all neuropeptides investigated was observed in all examined parts of the digestive system, both in control animals and in pigs after LPS administration

Summary

Introduction

The present research was conducted to investigate the influence of a low, single dose of LPS, which does not result in any clinical symptoms of intoxication on the expression of selected neuropeptides within the intestines of the domestic pig. A major topic of research interest has been the rise of the impact of the intestinal barrier, pathogenic and non-pathogenic bacteria on etiology and the pathogenesis or clinical course of neurodevelopmental, psychiatric and neurodegenerative diseases, such as depression, Alzheimer’s disease and Parkinson’s disease. In these pathological processes, neuropeptides have been the main subject of interest for neurodegeneration and neuroprotection. It is well-known that the digestive system is supplied by nerves derived from various neuronal cells. The ENS is built of millions of neuronal cells connected by dense nerve fibers and grouped into ganglionated plexuses [5].

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