Early phase of jejunal regeneration after short term ischemia in the rat
Menge, H.; Robinson, J.W.
Laboratory Investigation; A Journal of Technical Methods and Pathology 40(1): 25-30
1979
ISSN/ISBN: 0023-6837 PMID: 762952 Document Number: 148463
Short loops of rat intestine were subjected to 30 min of acute total ischemia by clamping all afferent and efferent vessels. Immediately and at various periods (1, 3, 6, 12 or 24 h) after the trauma, the tissues were excised for histologic and functional examination. At 1 h after insult most of the features of the acute damage, namely desquamation of the upper third of the villi and flattening of the crypt cells, were evident but occasionally a thin membrane or an irregular cubic epithelium covered the gaps at the tips of the shortened villi, no active accumulation of phenylalanine or .beta.-methylglucoside was detected in the tissue. Most villi were covered by a flat epithelium 3 h after the trauma; the mucosa was then the site of a finite active transport of phenylalanine and .beta.-methylglucoside in vitro. At the 6 h stage the villus height, the epithelial cell height, phenylalanine transport in vitro and glucose absorption in vivo were lower than the controls. After 24 h all parameters except glucose absorption had normalized and the crypts had become longer than the controls. The histologic picture recalled the former trauma in view of irregularities both in villus structure and in the epithelial layer. Results are interpreted in terms of a 3 stage regenerative process: the gaps at the tips of the villi are closed, presumably by damaged cells remaining on the sides of the villi; then the villi grow longer due to parallel proliferation of the epithelium and the lamina propria; this development is accompanied by the restoration of cellular transport processes and finally normalization of the structure of the enterocytes occurs.