The Effect of Ischemia and Reperfusion on Enteric Glial Cells and Contractile Activity in the Ileum.
BACKGROUND
We investigated the effects of ischemia followed by different periods of reperfusion (I/R) on immunoreactive S100β-positive glial and Hu-immunoreactive neurons co-expressing the P2X2 receptor in the myenteric plexus of the rat ileum.


METHODS
The ileal artery was occluded for 35 min with an atraumatic vascular clamp. The animals were killed 24 h, 72 h, and 1 week after ischemia. Sham animals were not submitted to ileal artery occlusion. The relative density, size, and co-localization of P2X2 receptor-expressing cells in relation to S100β-immunoreactive glial and Hu-immunoreactive neuronal cells were evaluated. Additionally, we analyzed the effects of I/R on gastrointestinal transit and ileum contractile activity.


RESULTS
The cellular density of P2X2 receptor and neuronal Hu immunoreactivity/cm(2) decreased after I/R, whereas glial S100β immunoreactivity/cm(2) increased. No significant differences between sham and I/R groups were observed regarding the perikarya area of Hu-positive neurons. The area of S100β-immunoreactive glial cells increased by 24.1 % 1 week after I/R compared with the 24 h group. Methylene blue progression along the small intestine decreased (P < 0.05) from 24.5 ± 2.3 % in the sham group to 17.2 ± 2.0 % 1 week post-ischemia. We noted a significant (P < 0.05) decrease in the maximal contraction amplitude triggered by electrical field stimulation in the presence of ATP in preparations submitted to 24 h of I/R.


CONCLUSIONS
Changes in the P2X2 receptor density parallel myenteric neuronal loss following I/R of the rat ileum. This, together with the increase in the activated (oversized) glial cells, may contribute to decreased GI motility after I/R.
Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Dr. Lineu Prestes, 2415, CEP 05508-900, São Paulo, Brazil.
Cristina Eusébio
CE
Mendes
Kelly
K
Palombit
Cátia
C
Vieira
Isabel
I
Silva
Paulo
P
Correia-de-Sá
Patricia
P
Castelucci
D000818:Animals; D005772:Gastrointestinal Transit / Q000502:physiology; D007082:Ileum / Q000098:blood supply*; D008297:Male; D009119:Muscle Contraction; D009130:Muscle, Smooth / Q000503:physiopathology*; D009197:Myenteric Plexus / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D009457:Neuroglia / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D009474:Neurons / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D051381:Rats; D017208:Rats, Wistar; D058476:Receptors, Purinergic P2X2 / Q000378:metabolism*; D015427:Reperfusion Injury / Q000503:physiopathology*; D064568:S100 Calcium Binding Protein beta Subunit / Q000378:metabolism
D058476:Receptors, Purinergic P2X2; D064568:S100 Calcium Binding Protein beta Subunit