Differential effects of intestinal ischemia and reperfusion in rat enteric neurons and glial cells expressing P2X2 receptors
Aline Rosa Marosti1, Marcos Vinícius da Silva1, Kelly Palombit1, Cristina Eusébio Mendes1, Wothan Tavares-de-Lima2 and Patricia Castelucci1
1Department of Anatomy and 2Department of Pharmacology/Biomedical Science Institute, University of São Paulo, São Paulo, Brazil
Offprint requests to: Dr. Patricia Castelucci, PhD, Assistant Professor, Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Dr. Lineu Prestes, 2415, CEP 05508-900, São Paulo, Brazil. e-mail: pcastel@usp.br
Summary. Background. Intestinal ischemia followed by reperfusion (I/R) may occur following intestinal obstruction. In rats, I/R in the small intestine leads to structural changes accompanied by neuronal death.
Aim. The objective was to analyze the impact of I/R injury on different neuronal populations in the myenteric plexus of the rat ileum after different periods of reperfusion.
Methods. The superior mesentery artery was occluded for 45 minutes, and animals were euthanized after 24 hours and 1 week of reperfusion. Immunohisto-chemical analyses were performed with antibodies against the P2X2 receptor in combination with antibodies against nitric oxide synthase (NOS), choline acetyltransferase (ChAT), calbindin, calretinin, the pan-neuronal marker anti-HuC/D, or S100? (glial marker).
Results. Dual immunolabeling demonstrated that approximately 100% of NOS-, ChAT-, calbindin-, and calretinin-immunoreactive neurons in all groups expressed the P2X2 receptor. Following I/R, the neuronal density decreased in the P2X2 receptor-, ChAT-, calretinin-, and HuC/D-immunoreactive neurons at 24 hours and 1 week following injury compared to the densities in the control and sham groups. The calbindin-immunoreactive neuron density was not reduced in any of the groups. The density of enteric glial cells increased by 40% in the I/R group compared to the density in the sham groups. We also observed increases of 12%, 16%, and 23% in the neuronal cell body profile areas of the NOS-, ChAT-, and calbindin-immunoreactive neurons, respectively, at 1 week following I/R. However, the average size of the calretinin-immunoreactive neurons was reduced by 12% in the I/R group at 24 hours.
Conclusions This work demonstrates that I/R is associated with a significant loss of different classes of neurons in the myenteric plexus accompanied by morphological changes and an increased density of enteric glial cells; all of these effects may underlie conditions related to intestinal motility disorder. Histol Histopathol 30, 489-501 (2015)
Key words: Chemical coding, Myenteric neurons, Ischemia and reperfusion, P2X2 receptor, Enteric glial cell
DOI: 10.14670/HH-30.489