Effects of aging on the architecture of the ileocecal junction in rats.
OBJECTIVE
To evaluate the structural organization of the elastic and collagen fibers in the region of the ileocecal transition in 30 young and old male Wistar rats.


METHODS
Histology, immunohistochemistry (IHC), transmission electron microscopy and scanning electron microscopy were employed in this study. The results demonstrated that there was a demarcation of the ileocecal region between the ileum and the cecum in both groups.


RESULTS
The connective tissue fibers had different distribution patterns in the two groups. IHC revealed the presence of nitric oxide synthase, enteric neurons and smooth muscle fibers in the ileocecal junctions (ICJs) of both groups. Compared to the young group, the elderly group exhibited an increase in collagen type I fibers, a decrease in collagen type III fibers, a decreased linear density of oxytalan elastic fibers, and a greater linear density of elaunin and mature elastic fibers.


CONCLUSIONS
The results revealed changes in the patterns of distribution of collagen and elastic fibers that may lead to a possible decrease in ICJ functionality.
Maria Cícera de Brito, Diego Pulzatto Cury, Department of Surgery, Faculty of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo 05508-900, Brazil.
Maria Cícera
MC
de Brito
Maria Cícera de Brito, Diego Pulzatto Cury, Department of Surgery, Faculty of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo 05508-900, Brazil.
Renato Paulo
RP
Chopard
Maria Cícera de Brito, Diego Pulzatto Cury, Department of Surgery, Faculty of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo 05508-900, Brazil.
Diego Pulzatto
DP
Cury
Maria Cícera de Brito, Diego Pulzatto Cury, Department of Surgery, Faculty of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo 05508-900, Brazil.
Ii Sei
IS
Watanabe
Maria Cícera de Brito, Diego Pulzatto Cury, Department of Surgery, Faculty of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo 05508-900, Brazil.
Cristina Eusébio
CE
Mendes
Maria Cícera de Brito, Diego Pulzatto Cury, Department of Surgery, Faculty of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo 05508-900, Brazil.
Patricia
P
Castelucci
Aging; Collagen fibers; Elastic fibers; Ileocecal junction; Rats