A new abdominal cavity chamber to study the impact of increased intra-abdominal pressure on microcirculation of gut mucosa by using video microscopy in rats.
OBJECTIVE
In experimental studies of capillary blood flow that use intravital video microscopy, organs are exposed in observation chambers implanted into the animal. In this article we describe an abdominal cavity chamber for intravital video microscopy of gut mucosa microcirculation during increased intra-abdominal pressure.


METHODS
Prospective, experimental animal study.


METHODS
Research laboratory at a university hospital.


METHODS
Male Wistar rats.


METHODS
The abdominal cavity chamber was designed for implantation into the abdominal wall of rats after laparotomy, thus creating an expanded hermetic, abdominal cavity volume. Animals were assigned to three levels of intra-abdominal pressure: controls (group 1), 10 mm Hg (group 2), and 15 mm Hg (group 3). Intra-abdominal pressure was increased by intra-abdominal insufflation of gas. By using a fluorescent marker, we quantitatively assessed mucosa perfusion index, functional capillary density, red blood cell velocity, capillary diameters, and flow motion during increased intra-abdominal pressure by intravital video microscopy. Results were expressed as mean +/- SEM. Significance of differences was determined by analysis of variance and multiple comparison of means with post hoc test (*p <.05 groups vs. control;p <.05 group 3 vs. group 2).


RESULTS
When compared with controls, animals subjected to an intra-abdominal pressure of 10 and 15 mm Hg showed a significant stepwise decrease in mucosa perfusion index (88%, 71%*, 22%*), functional capillary density (665.4 +/- 71.7, 461.6 +/- 71.9*, 375.1 +/- 2.0*cm(-1)), and red blood cell velocity (0.50 +/- 0.04, 0.33 +/- 0.03*, 0.04 +/- 0.06*mm/sec), indicating a stepwise impairment of mucosal microcirculation. Capillary diameters and flow motion did not change with respect to intra-abdominal pressure.


CONCLUSIONS
This novel animal model of intravital intestinal video microscopy that uses an abdominal cavity chamber is a feasible and sensitive experimental tool to study intestinal microcirculation during increased intra-abdominal pressure. Intra-abdominal pressure likely results in a severe impairment of mucosal microcirculation.
Samel
Stephan T
ST
Department of Surgery, University Hospital Mannheim, University of Heidelberg, Mannheim, Germany. stephan.samel@chir.ma.uni-heidelberg.de
Neufang
Thomas
T
Mueller
Alfred
A
Leister
Ingo
I
Becker
Heinz
H
Post
Stefan
S
D000005:Abdomen / Q000098:blood supply* / Q000502:physiology*; D000818:Animals; D001783:Blood Flow Velocity / Q000502:physiology; D001784:Blood Gas Analysis; D004867:Equipment Design; D007413:Intestinal Mucosa / Q000098:blood supply* / Q000502:physiology*; D007422:Intestines / Q000098:blood supply*; D008297:Male; D008833:Microcirculation / Q000502:physiology; D018613:Microscopy, Confocal; D018715:Microscopy, Video; D023421:Models, Animal; D010529:Peritoneal Cavity / Q000098:blood supply / Q000502:physiology; D011446:Prospective Studies; D051381:Rats; D017208:Rats, Wistar