Alteration in the neurochemical profile of ENS neurons in the porcine ileum after oral exposure of glyphosate

Abstract

Glyphosate-based herbicides are one of the most intensively used pollutants worldwide. The main goal of present study was to determine the changes in the neurochemical phenotype of enteric nervous system (ENS) neurons in the porcine ileum after oral glyphosate administration.Study was performed on 15 immature gilts divided into 3 groups: control (C) - animals receiving empty gelatin capsules; G1 - animals receiving a low dose of glyphosate- corresponding to the theoretical maximum daily intake (TMDI) - 0.05 mg/kg of b.w./day; G2- animals receiving a higher dose of glyphosate - corresponding to the acceptable daily intake (ADI) - 0.5 mg/kg of b.w./day) in gelatin capsules orally for 28 days. After this time, the animals were euthanized and ileum samples were collected. Frozen sections (12μm thick) were then subjected to the double immunofluorescent staining technique using primary antibody directed towards Hu C/D (used as a pan-neuronal marker) and pituitary adenylate cyclase-activating polypeptide (PACAP), neuronal nitric oxide synthase (nNOS), vesicular acetylcholine transporter (VAChT), cocaine and amphetamine-regulated transcript (CART) and appropriate secondary antibodies.Supplementation of lower dose of glyphosate increased the population of PACAP- like immunoreactive (LI) neurons in the outer submucous plexus (OSP) (from 6.34±1.24 to 14.12±1.68%), nNOS-LI neurons in the myenteric plexus (MP) (from 29.96±2.40 to 37.57±1.17%) and the inner submucous plexus (ISP) (from 12.64±1.10 to 19.76±1.34%), CART-LI neurons in the MP (from 20.44±0.81 to 29.77±1.16%) and the ISP (from 6.07±1.00 to 10.44±0.94%) and decreased the number of VAChT-LI neurons in both submucous plexuses (from 30.69±1.22 to 24.84±1.20% in the OSP and from 53.03±1.67 to 46.68±1.18% in the ISP). The higher dose of glyphosate evoke marked changes in the immunoreactivity of all neuroactive substance studied and type of enteric plexus analyzed. An increased number of PACAP-LI (from 13.75±to 40.20 to 40.20±1.62% in the MP, to 21.12 ±1.40% in the OSP and from 11.22±1.26 to 34.94±1.61% in the ISP), nNOS-LI (to 49.92±1.73% in the MP, from 19.53±1.29 to 27.69±1.29% in the OSP and to 27.92±1.26% in the ISP), CART-LI (to 35.03±1.67% in the MP, from 10.60±1.38 to 22.23±1.27% in the OSP and to14.78±1.53% in the ISP) neurons as well as a decrease in the population of VAChT-LI neurons (from 44.58±1.82 to 29.03±1.74% in the MP, to 22.24±1.96% in the OSP and to 35.87±1.42% in the ISP) were noted.Observed changes may result from neurotoxic effect of glyphosate on the ENS neurons and be part of adaptive processes of these neurons to ileum dysfunction. the National Science Centre in Poland [grant no. 2020/04/X/NZ7/00338]. Project financially supported by the Minister of Education and Science under the program entitled “Regional Initiative of Excellence” for the years 2019-2023, Project No. 010/RID/2018/19, amount of funding 12.000.000 PLN. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.