Microcirculatory heterogeneity in the rat small intestine during compromised flow conditions.
OBJECTIVE
To characterize and compare microcirculatory changes in the rat small intestinal tissue layers when temporal or spatial microvascular perfusion heterogeneity is present.


METHODS
Intravital videomicroscopy with an orthogonal polarization spectral imaging technique was used to visualize the microcirculation of the intestinal mucosa and the longitudinal muscle during systemic (hemorrhagic shock, endotoxemia, and nitric oxide synthesis inhibition) and local (ischemia-reperfusion) circulatory disorders. The average capillary red blood cell velocity (A-RBCV) was calculated from the relative durations of the observed velocity or as a function of the perfused area, respectively.


RESULTS
During hemorrhagic hypotension/resuscitation, timewise (flowmotion) and spatial heterogeneity were found to evolve in the mucosal villi and muscle layer. During resuscitation, the A-RBCV decreased by 40% in the villi and by 60% in the muscle. Reperfusion after a 30-min period of mesenteric ischemia caused a 20% reduction in A-RBCV in both layers, while endotoxin infusion caused a temporary 20% decrease in the mucosa, and a persistent, >25% decrease in the muscle. Nitric oxide synthesis inhibition resulted in spatial heterogeneity within the villi and in a 40% decrease in A-RBCV in both structures.


CONCLUSIONS
Calculations of timewise variability and of heterogeneity within and between layers can be used for the comparison of distinct intramural microcirculatory changes.
Department of Surgery, County Hospital, Kecskemét, Hungary.
Kornél
K
Vajda
Andrea
A
Szabó
Katalin
K
Kucsa
Béla
B
Suki
Mihály
M
Boros
D000009:Abdominal Muscles / Q000098:blood supply; D000818:Animals; D004731:Endotoxins / Q000494:pharmacology; D004912:Erythrocytes / Q000166:cytology; D006470:Hemorrhage / Q000503:physiopathology; D007022:Hypotension / Q000503:physiopathology; D007413:Intestinal Mucosa / Q000098:blood supply; D007421:Intestine, Small / Q000098:blood supply*; D008297:Male; D008833:Microcirculation / Q000503:physiopathology*; D018715:Microscopy, Video; D023421:Models, Animal; D009569:Nitric Oxide / Q000037:antagonists & inhibitors; D010477:Perfusion; D051381:Rats; D017208:Rats, Wistar; D012039:Regional Blood Flow; D013995:Time
D004731:Endotoxins; D009569:Nitric Oxide