Proliferating cells in the vertebrate small intestine: an immunohistocheniical study
In the small intestinal mucosa of healthy adult mammals proliferating cell are confined to the crypts of Lieberkiihn. Earlier radioautographic studies identified proliferative cells in the small intestine of several non-mammalian vertebrates. However, it is still not clear whether cell renewal is confined to proliferative compartment within the small intestinal mucosa in non-mammalian vertebrates. In the present study proliferative cells were identified using an immunological marker of cell proliferation, the proliferating cell nuclear antigen (PCNA) in the small intestine of several non-mammalian vertebrate species, including birds (zebrafinch, Poephila guttata), reptiles (green anole, Anolis carolinensis), amphibia (axolotl, Ambystoma mexicanum), and fishes (goldfish, Carassius auratus).Segments of the small intestine were fixed in 4% formaldehyde in 0.86 M phosphate buffer, pH=7.2 and embedded in paraffin. Deparaffinized and rehydrated sections were microwaved in citrate buffer. The immunohistochemical detection method used in this study based on the capillary action principle, as developed by Brigati.