Protein Restriction Produces Alterations in Nitrergic Myenteric Neurons in the Proximal Colon in Rats

Aim: This study aimed to investigate the effects of severe protein restriction on the morphometric and quantitative aspects of neurons in the myenteric plexus of the proximal colon in rats. Methodology: Ten rats were divided into two groups: (i) a normally fed group (NG) that received commercial chow with 26% protein for 90 days and (ii) a protein restriction group (RG) that received chow that contained a reduced amount of protein (4%) for 90 days. Nitrergic neurons were evaluated by nicotinamide adenine dinucleotide phosphate (NADPH-diaphorase) histochemistry. Intestinal segments were dissected. The number of neurons was counted, and the area of cellular bodies was measured. Results: A significant (58.92%) increase in the number of neurons that expressed NADPH-diaphorase and significant decreases in the area of cellular bodies, nuclei, and cytoplasm were found in the RG compared with the NG. Conclusion: In conclusion, protein restriction (from 26% to 4%) increased neuronal population density and nitrergic myenteric neuron atrophy in the proximal colon in rats.