Neurochemical characterization of nerve fibers in the porcine gallbladder wall under physiological conditions and after the administration ofSalmonella enteritidislipopolysaccharides (LPS)

Abstract

Lipopolysaccharides (LPS, bacterial endotoxin) are a component of the cellular membrane of Gram-negative bacteria, which is known as an important pathological factor. In spite of many previous studies describing multidirectional negative effects of LPS on living organisms, the knowledge concerning the influence of bacterial endotoxins on the gallbladder innervation is extremely scarce. The present study, based on the immunofluorescence technique, describes the changes in the neurochemical characterization of nerves within various parts of the porcine gallbladder (neck, body and fundus) after the administration of low doses of LPS. The obtained results show that even low doses of bacterial endotoxins affect the nerve structures within the gallbladder wall and the intensity of fluctuations in immunoreactivity to particular substances clearly depends on the part of the investigated organ. The most evident changes were observed in the case of fibers exhibiting the presence of neuropeptide Y (an increase from 7.84 ± 0.17 to 14.66 ± 0.37) in the neck, substance P (an increase from 0.88 ± 0.1 to 8.4 ± 0.3) in the body and the vesicular acetylocholine transporter in the gallbladder's fundus (an increase from 4.29 ± 0.18 to 11.01 ± 0.26). The mechanisms of the observed changes still remain unclear, but probably they are connected with the pro-inflammatory and/or neurodegenerative activity of LPS.

Neurochemical characterization of the enteric neurons within the porcine jejunum in physiological conditions and under the influence of bisphenol A (BPA)

“…The importance of these mechanisms has been highlighted by the introduction of the term “cholinergic anti‐inflammatory pathway” . Moreover, it is known that not only acetylcholine, but also VAChT may play a role in inflammatory processes and clearly influences the response of the body to inflammation induced by LPS . In turn, CART (despite appearing to be less important in the inflammatory processes) takes part in intestinal inflammation, as evidenced by the changes in CART expression in the ENS during experimental and “natural” inflammatory processes in the GI tract …”

“…60 Moreover, it is known that not only acetylcholine, but also VAChT may play a role in inflammatory processes and clearly influences the response of the body to inflammation induced by LPS. 28 In turn, CART (despite appearing to be less important in the inflammatory processes) takes part in intestinal inflammation, as evidenced by the changes in CART expression in the ENS during experimental and "natural" inflammatory processes in the GI tract. 22,29 However, signs of inflammatory processes were not observed during the present study, although changes in the neurochemical characterization of the enteric neurons may be the first subclinical symptoms of inflammation.…”

“…It has been reported that the ENS not only regulates the majority of the GI tract functions under physiological conditions, but also takes part in adaptive and protective mechanisms during various intra‐ and extra‐intestinal pathological processes, and changes in neurochemical characterization of the ENS may be the first subclinical signs of the impact of pathological factors and toxic substances …”

“…[23][24][25] It has been reported that the ENS not only regulates the majority of the GI tract functions under physiological conditions, but also takes part in adaptive and protective mechanisms during various intra-and extra-intestinal pathological processes, and changes in neurochemical characterization of the ENS may be the first subclinical signs of the impact of pathological factors and toxic substances. [26][27][28][29] It should be noted that previous studies have reported that BPA may change intestinal nociception and impair the gut barrier function. 1,30 It is also known that this substance can alter intestinal microbiota metabolism and is involved in pathogenesis of the inflammatory bowel disease.…”

Distribution and Neurochemistry of the Porcine Ileocaecal Valve Projecting Sensory Neurons in the Dorsal Root Ganglia and the Influence of Lipopolysaccharide from Different Serotypes of Salmonella spp. on the Chemical Coding of DRG Neurons in the Cell Cultures

“…Previous studies have also shown that LPS may affect the nervous system and is involved in, or connected with, neurodegenerative diseases. However, apart from the fact that LPS may change the expression of the neuronal factor in the internal organs [ 19 , 20 , 21 ], knowledge concerning changes in neurochemical characterization of neuronal cells under the influence of this substance is lacking. Moreover, it is known that LPS is not a homogeneous substance [ 22 , 23 , 24 , 25 , 26 ].…”