Rapid morphological changes and loss of collagen following experimental acute colonic obstruction.
OBJECTIVE
Anastomosis of an acutely obstructed colon is associated with an increased risk of dehiscence. In experimental models, acute obstruction decreases collagen in the colonic wall, but the time course and propagation along the colon of the biochemical changes are unknown. Furthermore, there is a paucity of information on the correlation between these biochemical changes and histological features.


METHODS
Forty male Sprague Dawley rats were subjected to partial obstruction by placing a silicone ring around the left colon 30 mm above the reflection. Obstruction was maintained for 0, 1, 2, 3 or 4 days. Samples from five different locations along the colon were analysed on circumference, tissue water content, collagen concentration and histomorphology. Neutrophil and macrophage infiltration was characterized immunohistochemically.


RESULTS
The colonic circumference and water content increased (p < 0.001), while the collagen concentration decreased by 48 % (p < 0.01) proximal to the obstruction already after 1 day. The degree of dilation and collagen reduction did not change significantly over the subsequent 3 days of obstruction, whereas the water content normalized by day 3. Mucosal and submucosal oedema and the relative neutrophil infiltration were highest after 1 day in the colonic segment proximal to the stenosis while the macrophage population continued to increase to day 4. Muscular necrosis in addition to ganglionitis and neuritis in the nervous plexus increased with duration of obstruction.


CONCLUSIONS
The pronounced and rapid changes of the composition of cells and the extracellular matrix of the colonic wall following acute obstruction may be of guidance for present surgical treatments and future pharmacological interventions.
Department of Surgery K, Bispebjerg University Hospital, Bispebjerg Bakke 23, 2400 Copenhagen, Denmark. krarup75@gmail.com
Peter-Martin
PM
Krarup
Martin
M
Rehn
Janna
J
Sand-Dejmek
Roy
R
Ehrnström
Magnus S
MS
Ågren
Ingvar
I
Syk
D000818:Animals; D003094:Collagen / Q000378:metabolism*; D003106:Colon / Q000378:metabolism / Q000473:pathology*; D007150:Immunohistochemistry; D007415:Intestinal Obstruction / Q000139:chemically induced / Q000378:metabolism* / Q000473:pathology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D014867:Water
D014867:Water; D003094:Collagen